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MyDeficiencies

Lactulose

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Findings for this medication

Research about this medication, graded for how strongly each finding can be attributed to it. Nothing here describes your own levels.

Lactulose has no classical depletion machinery. The label opened states it is poorly absorbed, with 3% or less recovered in urine within 24 hours, and that it reaches the colon essentially unchanged, where bacteria convert it to low molecular weight acids [1]. No human enzyme metabolism, CYP induction or inhibition, or renal tubular mechanism appears in any source opened (the FDA accessdata host was blocked, so this is an absence in the sources reached, not a verified negative). Its intended pharmacology is osmotic laxation, colonic acidification and conversion of ammonia to ammonium, which lowers blood ammonia [1], [3]. The fecal nitrogen shift this produces (reduced apparent nitrogen absorption in dogs [14]) is the drug working as designed and is not filed as a protein or nutrient deficiency (Hard Rule 2).

ATC A06AD11 · reviewed 2026-10-04. This describes research about the medication. It does not say anything about your own levels or health.

How to read the evidence grades

These colours describe how strongly a finding can be attributed to the medication in the research. They are not a severity score and they say nothing about your own health.

Grades describe how strongly a finding can be attributed to Lactulose in the research — not how common it is, how serious it would be, and not anything about you personally.

Red — Severe
Two or more independent Tier A sources, this drug in the cohort, the nutrient directly measured, consistent direction, clinically meaningful magnitude, a named mechanism, no substantial contradicting Tier A evidence.
Orange — Moderate
At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit.
Yellow — Low
Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction.
Not graded — disclosed evidence gap
Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result.Source definition: Not gradeable under the rules above because nothing has been measured. Published as a documented gap, never as reassurance that there is no effect.

What the research found

Sodium and fluid: hypernatremia in hospitalized cirrhosis patients with hepatic encephalopathy on high-dose, largely rectal lactulose (excess direction)

Orange — Moderate

See study details

In one inpatient cirrhosis cohort, 6% of patients with hepatic encephalopathy developed serum sodium of 150 mEq/L or higher, and daily rectal lactulose dose was the strongest independent predictor.

Full detail and limits

What the grade means here: At least one Tier A source with this drug in the cohort showing a real but bounded deficit: an exposure window, a subgroup, low frequency, or a functional rather than circulating deficit. Orange

Limits on what this shows

  • Confounding by hepatic disease: Presumed and not excluded. Every patient has cirrhosis with HE, and sicker patients plausibly receive more lactulose by dose escalation, so dose may partly track severity. The mortality difference (63% versus 35%) is an association within a very ill cohort and is not attributed to lactulose.
  • Negative and null findings: A secondary narrative review of low-dose lactulose (1-10 g/day) reports mild digestive symptoms and no serious adverse events across eight studies (n=519) in healthy adults [7]; that review has a manufacturer-affiliated author and is Tier C context only. Seki 2007 (n=24, 2 g or 4 g single doses) reported no side effects [8]. Neither population is comparable to inpatient HE.
  • At-risk subgroups: Hospitalized cirrhosis with HE on escalated or rectal lactulose; infants (label); older adults and acutely ill patients (Drugs.com adverse-effect text, [19]). Lithium users: dehydration can raise lithium toxicity risk [3].

Regulatory status

Label warning: excessive dosage may cause diarrhea with complications including loss of fluids, hypokalemia and hypernatremia; infants may develop hyponatremia and dehydration [1]. StatPearls describes lactulose as producing large changes in fluid and electrolyte status, most profound for sodium [3].

Population evidence

Tier A, observational (Rao 2025, J Clin Gastroenterol): 6,742 hospitalized cirrhosis patients 2018-2023; 1,651 (25%) had an HE diagnosis; 106 (6%) developed sodium of 150 mEq/L or higher. The hypernatremic group received a higher mean daily lactulose dose than matched controls (87 g versus 38 g); doses above 485 g over five days carried substantially elevated risk; 63% of hypernatremic patients died in hospital versus 35% of matched controls [11]. Abstract read through OpenAlex metadata; full text returned HTTP 402, so odds ratios and the matching method were not seen.

Mechanism

Named: osmotic diarrhea with fluid loss from a laxative given at high or rectal dose [1], [3]. The Rao abstract does not itself state a mechanism. This is a dehydration and retention-concentration disturbance, not a dietary sodium shortfall.

Counter-evidence held on record

Counter-evidence on record One retrospective study, abstract-level access only; no comparator group that was lactulose-free was described. Whether hypernatremia reflects lactulose dose or disease severity is not separable from the abstract. Framing caution This is a fluid-loss and sodium-excess risk. Adding salt or sodium is not the remedy and could be the hazard. Any dose change belongs to the prescriber; this finding does not apply to routine low-dose constipation use.

Magnesium: absorption enhanced in healthy men and dogs (reverse direction); effect at laxative doses not measured

Yellow — Low

See study details

In a controlled human isotope study, low-dose lactulose increased magnesium absorption; the opposite concern, magnesium loss with laxative-dose diarrhea, has no measured lactulose data in sources opened.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Negative and null findings: No study located measured serum or tissue magnesium in lactulose users. Single-dose isotope absorption is not a status measure.
  • At-risk subgroups: Not defined. Cirrhosis and diuretics carry their own magnesium risks that are not attributable to lactulose (reasoning, not drawn from a source).

Regulatory status

The label opened names hypokalemia and hypernatremia with excess dosing but does not name magnesium [1].

Population evidence

Tier A, surrogate outcome. Seki 2007 (J Nutr Sci Vitaminol): n=24 healthy adult men, double-blind randomized crossover, 0, 2 or 4 g lactulose; urinary stable-isotope Mg ratio rose dose-dependently, significant versus placebo at both 2 g and 4 g (p<0.01); urine collected 8 hours; no side effects; bone-resorption markers unchanged [8]. Tier B: Beynen 2001, n=6 dogs, Latin square, 1 or 3 g lactulose per MJ metabolizable energy, dose-dependent rise in apparent Ca and Mg absorption [14].

Mechanism

Plausible and consistent with fermentation lowering colonic pH and improving mineral solubility, as proposed in a secondary review [7]; not demonstrated in [8].

Counter-evidence held on record

Counter-evidence on record Doses of 2 to 4 g are far below the 20 to 40 g daily laxative or HE range, so the absorption finding does not extend to laxative dosing. Framing caution This runs opposite to depletion. It is not a reason to supplement magnesium, and it does not exclude loss during diarrhea at high dose.

Potassium: loss with overdose-related diarrhea, label-level only

Yellow — Low

See study details

The label and a drug-reference page name hypokalemia as a consequence of excessive dosing with severe diarrhea; no lactulose cohort with measured potassium was located.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Confounding by hepatic disease: In HE the setting adds diuretics and poor intake (reasoning, not drawn from a source); attribution to lactulose cannot be made from the sources opened.
  • Negative and null findings: Not found; no potassium-neutral study located either.
  • At-risk subgroups: Elderly or acutely ill patients with severe diarrhea [19].

Regulatory status

Label: excessive dosage may cause diarrhea with loss of fluids, hypokalemia and hypernatremia [1]. Drugs.com adverse-effect text repeats this and adds hyperchloremic metabolic acidosis, as a result of severe diarrhea, especially in elderly or acutely ill patients [19].

Population evidence

None measured. Regulatory warning text and a derived reference page only; no study with a serum potassium endpoint in lactulose users was located. Held at yellow because the mechanism is named but no data were opened.

Mechanism

Named: gastrointestinal potassium loss with high-volume diarrhea (mechanism class: altered transit and fluid loss). It is the drug's intended osmotic action taken to excess.

Counter-evidence held on record

Counter-evidence on record Label warnings are not measurements; the Drugs.com page shares its text origin with the label (see Overlap map). Framing caution This is fluid-loss-related potassium disturbance from excess dosing. It does not support routine potassium supplementation and is not a dietary shortfall.

Fat-soluble vitamins A, D, E, K: a steatorrhea outcome in cirrhosis, vitamins not measured

Yellow — Low

See study details

OUTCOME ENTRY. In 18 patients with Child-Pugh A or B cirrhosis, lactulose or lactitol titrated to two semiliquid stools a day was followed by mild steatorrhea in half the patients; no vitamin level was measured, so no vitamin deficiency is claimed (Hard Rule 2).

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Confounding by hepatic disease: Strong. The same abstract states that mild to moderate fat malabsorption frequently occurs in cirrhosis itself [12]; there was no untreated comparator group, so the lactulose contribution is not isolated.
  • Negative and null findings: No vitamin measurement in any lactulose cohort was located. Seki 2007 found no change in bone-resorption markers (not a vitamin D measure) [8].
  • At-risk subgroups: Cirrhosis with fat malabsorption. Not defined for lactulose specifically.

Regulatory status

No fat-soluble vitamin statement in the label text read [1].

Population evidence

Merli 1992 (J Clin Gastroenterol), before-after, n=18 Child-Pugh A or B cirrhosis without prior absorption-affecting therapy, lactulose or lactitol dosed to two semiliquid stools daily, steatorrhea measured before and after at least 7 days; both disaccharides induced mild steatorrhea in half the patients with no significant difference between them; the summary also states fecal fat exceeded 10 g/day in patients using lactulose, without giving the number of patients [12]. Abstract read through OpenAlex metadata. The lactitol arm means the cohort is mixed.

Mechanism

Plausible, not demonstrated in the source: accelerated transit or osmotic stool volume could reduce fat absorption, which could lower fat-soluble vitamin uptake. No vitamin A, D, E or K assay was reported.

Counter-evidence held on record

Counter-evidence on record Small uncontrolled study in a disease that causes the same finding; the practitioner claim that lactulose depletes vitamins A, D, E and K cites nothing [20]. Framing caution Steatorrhea is a clinical outcome, not a vitamin deficiency. Do not read this as evidence that lactulose lowers vitamin A, D, E or K, and do not prompt vitamin supplementation from it.

Zinc: indication-linked low zinc in cirrhosis and HE, not attributable to lactulose (context flag)

Yellow — Low

See study details

Low serum zinc is documented in chronic liver disease and tracks HE severity; this is disease-linked and lactulose was not shown to change zinc.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Confounding by hepatic disease: Total. Under Hard Rule 6, confounding by indication is presumed: zinc is low in the disease that lactulose treats.
  • Negative and null findings: No lactulose-versus-no-lactulose zinc comparison located.
  • At-risk subgroups: Decompensated cirrhosis with HE, by disease.

Regulatory status

No zinc statement in the label text read [1].

Population evidence

Tier C context. Yogappanavar 2023 (J Contemp Clin Pract): cross-sectional, n=30 decompensated chronic liver disease, mean serum zinc 63.97 ug/dL; lower zinc correlated with higher HE grade (r=-0.679, p<0.001); overt HE 43.5 ug/dL versus minimal or absent 69 ug/dL [15]. Lactulose use in this cohort was not reported in the abstract. Almansouri 2025 (Clin Exp Hepatol): zinc plus lactulose versus lactulose alone in minimal HE; the abstract reports p=0.104 for the benefit, which is not significant, although its conclusion states benefit; this trial supplemented zinc and did not measure a lactulose effect on zinc [16].

Mechanism

Absent for lactulose. No source describes lactulose binding or wasting zinc. Disease-linked zinc loss in cirrhosis is the proposed context.

Counter-evidence held on record

Counter-evidence on record The practitioner claim that laxatives deplete zinc [20] has no citation; the cohort data point to the underlying disease. Framing caution Do not attribute low zinc to lactulose. Zinc status in cirrhosis is a disease-management question for the treating clinician; this dossier makes no dosing statement.

B vitamins other than B12 (microbial synthesis, e.g. folate)

Not graded — disclosed evidence gap

See study details

Bifidobacteria can synthesize folate in vitro, but no study connected lactulose to folate or another B vitamin, and no claim circulates for them (B12 is rebutted separately).

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. Ungraded

Limits on what this shows

  • Why no grade: Dual condition met. D'Aimmo 2012 screened 19 bifidobacterial strains in vitro; 10 produced folate autotrophically and 9 did not [17]. That is a strain-level organism study with no lactulose exposure and no host measurement, so it is neither Tier B nor Tier C for this drug. The two-step chain (lactulose, then bifidobacteria, then folate) is unmeasured, and the direction would be protective if real. Classification: partly tooling-limited.

Channels tried

Crossref "lactulose folate vitamin B synthesis bifidobacteria": 8 results, none measuring a vitamin in lactulose users. One in-vivo probiotic folate rat study appeared in that listing; its abstract could not be retrieved (OpenAlex returned no abstract) so it was not used. Crossref "lactulose vitamin K folate thiamine riboflavin status" (revision): HTTP 429, not retrieved. PubMed: 429.

Revisit

PubMed "lactulose AND (folate OR thiamine OR biotin OR vitamin K)" when reachable.

The five body-system areas

Each finding is counted once, in a single area. Where a study is mentioned in a second area it is context only.

Mitochondrial Burden

Each finding below is counted once, in this area only.

Mitochondrial burden

Not graded — disclosed evidence gap

See study details

No lactulose study of mitochondrial structure, electron transport or biogenesis was located, and no such claim circulates.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. Ungraded

Limits on what this shows

  • Why no grade: Dual condition met after the revision searches: no Tier B or C source measuring mitochondrial structure, electron transport or biogenesis with lactulose, and no mitochondrial claim in the pages opened [19], [20], [21]. Classification: partly tooling-limited, not a confirmed gap.

Channels tried

Crossref "lactulose mitochondrial function ATP": 8 results, none with lactulose as intervention. Crossref "lactulose mitochondria butyrate colonocyte" (revision): 5 results, all direct butyrate or colonocyte biology (for example butyrate oxidation in colonocytes, iScience 2024), none with lactulose as the intervention. PubMed listing "lactulose oxidative stress rats" (revision, answered): the lactulose records returned measured ROS, MDA or SOD, not mitochondrial structure, electron transport or biogenesis; the one lactulose redox study opened [22] did not measure mitochondria. Crossref "lactulose mitochondrial dysfunction hyperammonemia rats" and an OpenAlex works search: HTTP 429 (tool asked not to retry). WebSearch exhausted. Lactulose to SCFA/butyrate to colonocyte mitochondria is a plausible chain but no lactulose study measuring it was opened, so it is not asserted.

Revisit

Re-run PubMed and Europe PMC with "lactulose" plus "mitochondria", "colonocyte", "butyrate" and "hyperammonemia" when those hosts answer. Any mitochondrial work in HE models would reflect disease pathophysiology and would need a lactulose-free comparator.

Oxidative Stress

Each finding below is counted once, in this area only.

Oxidative stress: protective direction in one rat methamphetamine-toxicity model, no human data (reverse direction)

Yellow — Low

See study details

In one rat model of methamphetamine neurotoxicity, lactulose pretreatment lowered striatal reactive oxygen species and malondialdehyde; this is an animal, toxin-model finding in the protective direction, not a depletion, and no human oxidative-stress measurement in lactulose users was opened.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Confounding by hepatic disease: The model is a toxin model in non-cirrhotic rats, so cirrhosis is not a confounder here, but it also means the finding does not describe human hepatic encephalopathy. In human HE, liver disease itself plausibly alters redox status (reasoning, not drawn from a source), so any lactulose-attributable change in a patient cohort would be inseparable from disease course; no human cohort of this kind was opened.
  • Negative and null findings: There was no lactulose-alone group, so lactulose effects on redox markers in unchallenged animals were not tested [22]. SOD and GSH were not measured. A second rat study (Yu 2015, J Surg Res, partial hepatectomy) was described in a PubMed listing summary as showing higher liver SOD and lower MDA with lactulose, but its abstract could not be opened (OpenAlex and Crossref returned no abstract; PubMed record and DOI pages were rate-limited), so it is not cited as evidence and supports no part of this grade.
  • At-risk subgroups: None defined. No harm direction was identified.

Regulatory status

No oxidative stress or antioxidant statement in the label text read [1].

Population evidence

Tier B, animal, lactulose administered directly. Xie 2018 (Front Neurosci): male Sprague Dawley rats, n=18 (6 per group, from the Methods as read through a fetch tool), three groups: control, methamphetamine (METH) alone, METH plus lactulose. Lactulose 5.3 g/kg by oral gavage every 12 hours starting 2 days before METH (15 mg/kg intraperitoneal, 8 injections at 12-hour intervals). METH raised striatal ROS and MDA; lactulose pretreatment significantly attenuated that rise, lowered protein levels of TLR4, MyD88, TRAF6, NFkB, IL-1 beta, IL-6, TNF-alpha, cleaved caspase 3 and PARP-1, raised Nrf2, p62 and HO-1 mRNA, and reduced METH-induced cytoplasmic damage in liver on histology. No numeric effect sizes were seen in the abstract [22]. Not class extrapolation: lactulose was the tested drug.

Mechanism

Proposed by the authors, not proven: activation of the Nrf2/HO-1 axis with suppressed neuroinflammation, stated in the abstract as "might be attributed" [22]. A single-lab hypothesis.

Counter-evidence held on record

Counter-evidence on record One small single-species study (n=18) with a high gavage dose given every 12 hours, no lactulose-alone arm and no human replication located. Its relation to human dosing was not assessed. Framing caution This is a protective-direction animal finding, not an antioxidant depletion. Do not present lactulose as an antioxidant therapy, and do not use it as a reason to add antioxidant supplements.

Copper and Iron Balance

Copper and iron are assessed separately. Nothing here is counted twice.

Copper

Not graded — disclosed evidence gap

See study details

No lactulose study measured copper or ceruloplasmin, and no copper claim for this drug was found.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. Ungraded

Limits on what this shows

  • Why no grade: Dual condition met: no Tier B or C source, and none of the claim pages opened mentions copper [19], [20], [21]. Classification: likely genuine gap on the Crossref channel, with PubMed unreachable. Copper stays independent of Iron.

Channels tried

Crossref "lactulose copper ceruloplasmin": 8 results, all general copper biology, none with lactulose. Crossref "lactulose serum copper ceruloplasmin cirrhosis" (revision): HTTP 429, not retrieved. The rat mineral study [13] measured nitrogen, calcium, phosphorus and iron only. PubMed: 429.

Revisit

PubMed "lactulose AND copper" when reachable.

Gut Microbiome Risk

Each finding below is counted once, in this area only.

Gut microbiome risk: bifidogenic shift in healthy adults, inconsistent in cirrhosis (reverse direction, not harm)

Yellow — Low

See study details

Lactulose is fermented by colonic bacteria and raises fecal bifidobacteria in healthy volunteers at 1 to 10 g/day; a composition change is not a nutrient deficiency, and no source linked it to harm.

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Confounding by hepatic disease: The HE and cirrhosis literature is confounded because cirrhosis itself alters gut flora. Murawaki 2000 (n=6 compensated cirrhosis, 30-60 mL of 60% syrup daily for 2 weeks, before-after): Bifidobacterium proportion rose, Bacteroides and Lactobacillus rates fell, total anaerobes rose, fecal organic acids unchanged [10]; this summary was read through a fetch tool. Sarangi 2017 (n=35 cirrhosis, 18 healthy controls, 21 paired post-lactulose samples, 30-60 mL/day, median 55 days): no change in alpha or beta diversity or any taxon at any level [9].
  • Negative and null findings: Sarangi 2017 is a null for composition in cirrhosis [9]. Bouhnik found no change in Lactobacillus or fecal pH [4], whereas Murawaki saw Lactobacillus fall [10]. No study located linked these shifts to any vitamin, mineral or antioxidant outcome.
  • At-risk subgroups: None defined. No harm direction was identified in any source.

Regulatory status

Label and StatPearls state the mechanism depends on bacterial fermentation and colonic acidification [1], [3]. No microbiome warning is in the label text read.

Population evidence

Tier A, lactulose in cohort. Bouhnik 2004 (Eur J Clin Nutr): n=16 healthy volunteers, randomized double-blind parallel, 10 g/day for 6 weeks versus sucrose placebo; bifidobacteria 8.25, 8.96 and 9.54 log CFU/g at baseline, week 3 and week 6 (P=0.048), no change in placebo; total anaerobes, Lactobacillus and fecal pH not significantly changed; excess flatus more common (P=0.03) [4]. Sakai 2019 (Benef Microbes): n=52 analyzed, randomized double-blind crossover, 2 g/day for 2 weeks; bifidobacteria 9.53 versus 9.16 log CFU/g (P<0.0001) [5]. Sakai 2018: n=26, open-label before-after, 1, 2 or 3 g/day, bifidobacteria increased [6]. Same research group for [5] and [6]. A narrative review reports further primary studies (including n=304 at 4 g/day) that were not opened [7].

Mechanism

Named and documented: substrate fermentation yielding organic acids and lower colonic pH [1], [3].

Counter-evidence held on record

Counter-evidence on record Sarangi 2017 found no composition change in cirrhosis [9]; the volunteer trials report CFU counts (log CFU/g) in small samples, not whole-community sequencing, so they speak to bifidobacteria only. Framing caution An increase in bifidobacteria is a documented prebiotic-type effect, not damage and not a depletion. Do not present it as dysbiosis or as a reason to add probiotics or supplements.

Oxygen and ATP Output

Oxygen delivery and ATP production are assessed separately. Nothing here is counted twice.

Oxygen delivery/utilization: low hemoglobin in hepatic encephalopathy cohorts, indication-linked and not attributable to lactulose (outcome entry)

Yellow — Low

See study details

OUTCOME ENTRY. Low hemoglobin is documented in cirrhosis cohorts with hepatic encephalopathy, where lactulose is the standard therapy; no study opened isolated an effect of lactulose on hemoglobin, so it is not filed as a lactulose effect, an iron deficiency or a nutrient deficiency (Hard Rules 2 and 6).

Full detail and limits

What the grade means here: Mechanistic plausibility only (Tier B), or class extrapolation (Tier C) with no drug-specific human status data; also used for context flags and interactions running the other direction. Yellow

Limits on what this shows

  • Confounding by hepatic disease: Total. Both cohorts are selected for advanced liver disease with HE or bleeding, and anemia is part of that picture. Under Hard Rule 6, confounding by indication is presumed and not excluded.
  • Negative and null findings: Nagendra 1994 (weanling rats, 0.5-1.0% lactulose in formula for five weeks) reported no effect on growth, blood composition or liver histology, though the abstract does not name hemoglobin [13]. No human lactulose-versus-no-lactulose hemoglobin comparison was located. Neither [23] nor [24] reports a hemoglobin change after lactulose.
  • At-risk subgroups: Cirrhosis with HE or gastrointestinal bleeding, by disease. Not defined for lactulose.

Regulatory status

No hemoglobin or anemia statement in the label text read [1].

Population evidence

Tier C context; lactulose was in both cohorts but the hemoglobin finding is not stratified to lactulose, so this is not class extrapolation and not drug-specific evidence. Alexandrescu 2025 (J Clin Med): retrospective cohort, n=120 adults with cirrhosis and HE, one Romanian hospital, 2022 to 2025; mean hemoglobin 9.35 g/dL; lactulose given to 63.3% and rifaximin to 52.5%, alongside diuretics, pantoprazole and albumin; the abstract reports no hemoglobin comparison by lactulose use [23]. Wen 2013 (Digestion): randomized controlled trial, n=128 cirrhosis patients with upper gastrointestinal bleeding, lactulose (n=63) versus no lactulose (n=65) for 6 days; HE occurred in 2 versus 11 patients; patients who developed HE had lower hemoglobin than those who stayed HE-free (72.31 +/- 15.15 versus 87.45 +/- 19.79, p<0.05; units not stated in the abstract). Here hemoglobin is a baseline predictor of HE in a bleeding cohort and not an outcome of lactulose; the abstract reports no hemoglobin by arm [24].

Mechanism

Absent for lactulose: no source opened describes lactulose affecting red-cell mass, hemoglobin or oxygen transport. Bleeding is the stated setting in [24]; other disease drivers of anemia in cirrhosis are not drawn from a source opened here.

Counter-evidence held on record

Counter-evidence on record [23] is descriptive with no comparator and [24] used hemoglobin as a prognostic variable; neither tests lactulose against non-use for hemoglobin. The iron claim for lactulose fails verification separately and anemia is not iron deficiency. Framing caution Do not read this as lactulose lowering hemoglobin, as reduced oxygen-carrying capacity from lactulose, or as iron deficiency. Anemia in HE is a disease-management question for the treating clinician; this dossier prompts no iron or other supplementation.

ATP production

Not graded — disclosed evidence gap

See study details

No lactulose study of cellular ATP synthesis was located, and no "low energy" claim for it was found.

Full detail and limits

What the grade means here: Nothing has been measured here, so this finding cannot be graded. That does not establish either safety or harm, and it is not the same as a White result. Ungraded

Limits on what this shows

  • Why no grade: Dual condition met. Independent of Mitochondrial burden and Oxygen delivery/utilization (the latter is now a graded yellow outcome entry on a different evidence base); ATP and Mitochondrial burden share only the same absence (Overlap map). Classification: partly tooling-limited.

Channels tried

The same Crossref ATP query as Mitochondrial burden (8 results, none with lactulose), plus the revision queries listed under Mitochondrial burden (Crossref butyrate/colonocyte: no lactulose; Crossref and OpenAlex mitochondrial-dysfunction searches: HTTP 429). No lactulose study with an ATP, energy-charge or oxygen-consumption endpoint was seen in any listing opened. PubMed: 429.

Revisit

PubMed "lactulose AND (ATP OR energy metabolism)" when reachable.

Claims checked and not supported

These circulate online for this medication. They are listed here only so they can be answered, never as findings, and they are not graded.

A claim with no supporting evidence is not necessarily disproven. Where evidence actually argues against a claim, that is stated below.

  • Iron depleted by lactulose (independent entry, not merged with Copper)

    Where it comes from: Practitioner list grouping mineral oil, lactulose, MiraLAX and senna [20]; no citation

    Why it fails: No human study of iron status was located. In weanling rats, lactulose at 0.5-1.0% in formula for five weeks produced no significant difference in iron absorption or retention (56-77% range for calcium and iron) [13]. No mechanism for iron binding or loss appears in any source opened.

  • Vitamin B12 depleted by lactulose

    Where it comes from: Same list [20]; no citation

    Why it fails: No B12 measurement in any lactulose cohort was located and no mechanism is named. Pooling lactulose with other laxatives is not a cohort test, and no mechanism from the other agents is carried over (Hard Rule 6).

  • Calcium depleted by lactulose

    Where it comes from: Same list [20]; no citation

    Why it fails: The direction is reversed by this drug's own data: lactulose increased calcium absorption in healthy men (significant at 4 g versus placebo, p<0.01) with unchanged bone-resorption markers [8], and in dogs [14]. A secondary review also reports higher calcium absorption in 12 postmenopausal women at 10 g/day [7] (primary not opened).

How the body handles this medication

Absorption
Poorly absorbed; only small amounts reach the blood. Not hydrolyzed by human intestinal enzymes in the sources opened; it reaches the colon unchanged. Label text was read through a summarizing fetch tool.[1], [3]
Metabolism and CYP450
Metabolized by colonic bacteria to low molecular weight acids (label) or volatile fatty acids, hydrogen and methane (StatPearls). No CYP induction, inhibition or hepatic metabolism is described in either source. Absence in the sources reached, not a verified negative.[1], [3]
Elimination
3% or less of an oral dose is excreted in urine within 24 hours; the remainder is fermented or passes in stool. No renal tubular handling of water or electrolytes is described.[1], [3]
Intended mechanism
Colonic acidification converts NH3 to NH4+, trapping it; the label reports a 25-50% fall in blood ammonia with clinical improvement in about 75% of patients. StatPearls adds laxative effect from gas and osmolality, bacterial ammonia uptake, and loss of urease-producing bacteria at low pH.[1], [3]
Electrolyte and special populations
Label: excessive dose may cause diarrhea with loss of fluids, hypokalemia and hypernatremia; infants may develop hyponatremia and dehydration. Contains galactose (under 1.6 g/15 mL): contraindicated with a low-galactose diet; use cautiously in diabetes. Pregnancy: Category B in the label, no adequate human trials.[1]
Interactions and identity
Neomycin and possibly other anti-infectives may impair lactulose degradation; nonabsorbable antacids may blunt the pH drop (these are other drugs acting on lactulose, not depletions). StatPearls notes lithium toxicity via dehydration. WHO DDD 6.7 g oral (A06AD11).[1], [3], [2]

What the research says is worth watching

General information from the medication label and the studies above. It is not personal medical advice, and any change belongs with your prescriber.

  • Labs, conditional

    Serum sodium and osmolality

    Reasonable in hospitalized cirrhosis with HE on escalated, rectal or prolonged lactulose, and in frail or older patients with persistent watery diarrhea. Based on one observational study [11] and the label [1]; not a routine screen for low-dose constipation use.

  • Labs, conditional

    Potassium and magnesium

    Check when diarrhea is severe or prolonged, or alongside diuretics. Potassium rests on label text [1]; magnesium has no loss data in lactulose users.

  • Fluid

    Stool frequency and hydration

    Dosing in the cirrhosis cohort [9] was adjusted to two to three semisolid stools daily. Frequent watery stools or dehydration signs warrant a dose review by the prescriber, who also manages the lithium interaction risk from dehydration [3].

  • Timing and interactions

    Anti-infectives and antacids

    Neomycin and possibly other anti-infectives may interfere with lactulose degradation; nonabsorbable antacids may blunt the colonic pH fall [1]. These act on lactulose, not on a nutrient. The label opened states no separation interval, so none is given.

  • Special populations

    Galactose, diabetes, pregnancy, infants

    Contraindicated in low-galactose diets and used cautiously in diabetes [1]. Label lists pregnancy as Category B with no adequate human trials, and infants may develop hyponatremia and dehydration [1]. Renal impairment: no lactulose nutrient data located.

  • Not recommended

    Supplements

    No nutrient reached a grade that supports supplementation. The orange sodium finding is an excess direction: do not add salt. Do not add vitamins, minerals or probiotics on the basis of this dossier.

Overlap map, to prevent double counting

  • Sodium and fluid; Potassium

    Shares evidence with: Each other; Drugs.com page [19]

    Note: Both rest on the same label sentence about excess dosing causing diarrhea with loss of fluids, hypokalemia and hypernatremia [1], restated in [19] and [3]. Rao 2025 [11] adds a measured sodium cohort for Sodium only. Do not count the label, StatPearls and Drugs.com as three lines of confirmation.

  • Gut microbiome risk; Magnesium

    Shares evidence with: Fermentation and colonic pH mechanism; review [7]

    Note: The proposed Magnesium mechanism is the same fermentation and pH chain that underlies the microbiome signal. Seki 2007 [8] supplies the only measured human Magnesium data and the white Calcium rebuttal as well. One study, three uses.

  • Magnesium; Calcium (white)

    Shares evidence with: Seki 2007 [8]; Beynen 2001 [14]

    Note: Same two studies measure both minerals. Calcium is rebutted in Fails verification, Magnesium graded here; they are one evidence body.

  • Iron (white); Oxygen delivery/utilization

    Shares evidence with: Nagendra 1994 [13]

    Note: One rat study (iron absorption null; no change in blood composition) is cited in both as a null. It is not human data and is not two confirmations. Oxygen delivery/utilization is otherwise graded on separate sources [23], [24].

  • Gut microbiome risk

    Shares evidence with: Sakai 2019 [5] and Sakai 2018 [6]

    Note: Same research group and country; patient overlap unverified. Bouhnik [4] is independent. Murawaki [10] and Sarangi [9] are the two cirrhosis cohorts and disagree.

  • Fat-soluble vitamins; Zinc; Oxygen delivery/utilization

    Shares evidence with: Cirrhosis and HE confounding

    Note: All three are entries where the underlying liver disease, not lactulose, is the likely driver (Merli [12], Yogappanavar [15], Alexandrescu [23], Wen [24]). They share a confounder and a patient population type, not a source; the two HE cohorts [15] and [23] are different hospitals and different outcomes.

  • Oxidative stress

    Shares evidence with: Single rat study [22]

    Note: Rests on one study; its inflammation, apoptosis and liver-histology observations are part of the same experiment and are not independent confirmation. The Yu 2015 rat lead was not opened and is not counted.

  • Mitochondrial burden; Copper; ATP production; B vitamins

    Shares evidence with: Same Crossref null result sets and the same unreachable PubMed channel

    Note: One gap in the record with a shared channel limitation, not four independent checks. Copper and Iron are independent entries and share only this tooling limit. Oxygen delivery/utilization (now yellow, outcome entry) and ATP production remain independent entries.

All references used above
  1. Lactulose Solution USP 10 g/15 mL, Rising Pharma Holdings, DailyMed label. Tier A, regulatory label. — Clinical pharmacology (poor absorption, 3% or less urinary, colonic acids, NH3 to NH4+ trapping, 25-50% ammonia reduction), contraindications, warnings (fluid loss, hypokalemia, hypernatremia; infants), interactions, pregnancy. Read through a summarizing fetch tool, not the raw label text. Other lactulose labels in the DailyMed listing (Bajaj Medical, Kesin Pharma repackaged) were not opened.
  2. WHO Collaborating Centre for Drug Statistics Methodology, ATC/DDD Index, A06AD11 lactulose (page updated 2026-01-20). — DDD 6.7 g, oral; osmotically acting laxatives.
  3. Lactulose, StatPearls. Tier B, established pharmacology reference. — Mechanism, pharmacokinetics, electrolyte and sodium effects, lithium interaction, urease-producing bacteria. Read through a summarizing fetch tool.
  4. Bouhnik Y, Attar A, Joly FA, Riottot M, Dyard F, Flourie B. Lactulose ingestion increases faecal bifidobacterial counts: a randomised double-blind study in healthy humans. Eur J Clin Nutr, 2004. Tier A. DOI 10.1038/sj.ejcn.1601829; PMID 14985684. — n=16, 10 g/day for 6 weeks versus sucrose placebo. Abstract opened on the publisher page (via summarizing fetch tool).
  5. Sakai Y, Seki N, Hamano K, Ochi H, Abe F, Masuda K, Iino H. Prebiotic effect of two grams of lactulose in healthy Japanese women: a randomised, double-blind, placebo-controlled crossover trial. Benef Microbes, 2019. Tier A. DOI 10.3920/bm2018.0174; PMID 31131617. — n=52 analyzed of 60, 2 g/day for 2 weeks. Abstract read from OpenAlex reconstructed text. A fecal pH figure in that text was garbled and was not used.
  6. Sakai Y, Seki N, Hamano K, Ochi H, Abe F, Shimizu F, Masuda K, Iino H. A study of the prebiotic effect of lactulose at low dosages in healthy Japanese women. Biosci Microbiota Food Health, 2018 (OpenAlex year; PubMed listing shows 2019). Tier A, open-label. DOI 10.12938/bmfh.18-013; PMID 31106110. — n=26, 1, 2 or 3 g/day for 2 weeks each. Abstract from OpenAlex.
  7. Karakan T, Tuohy KM, Janssen-van Solingen G. Low-dose lactulose as a prebiotic for improved gut health and enhanced mineral absorption. Front Nutr, 2021. Narrative review, Tier C context. DOI 10.3389/fnut.2021.672925; PMID 34386514. — Source of figures for primary studies not opened (n=304 at 4 g/day; n=12 postmenopausal calcium absorption; n=519 safety pool). One author is affiliated with Abbott, a lactulose manufacturer. Read through a summarizing fetch tool.Secondary review: supports nothing above yellow and is not used for any grade on its own.
  8. Seki N, et al. Effect of lactulose on calcium and magnesium absorption: a study using stable isotopes in adult men. J Nutr Sci Vitaminol, 2007;53(1):5-12. Tier A. DOI 10.3177/jnsv.53.5. — n=24, double-blind randomized crossover, 0, 2 or 4 g. Abstract opened on J-STAGE (via summarizing fetch tool). Author list beyond the first author was not captured; first author from the Crossref listing.
  9. Sarangi AN, et al. Faecal bacterial microbiota in patients with cirrhosis and the effect of lactulose administration. BMC Gastroenterol, 2017. Tier A. DOI 10.1186/s12876-017-0683-9. — n=35 cirrhosis, 18 controls, 21 paired post-lactulose samples, median 55 days. Opened on the Springer page (via summarizing fetch tool). Cirrhosis cohort: hepatic disease confounds. The first author name came from the Crossref listing; other authors were not captured.
  10. Murawaki Y, et al. Effects of lactulose on intestinal bacterial flora and fecal organic acids in patients with liver cirrhosis. Hepatol Res, 2000. Tier A (small). DOI 10.1016/s1386-6346(99)00063-7. — n=6 compensated cirrhosis, before-after. Abstract opened via a summarizing fetch tool on ScienceDirect. Cirrhosis cohort: hepatic disease confounds.
  11. Rao AK, Gregoski MJ, Ibrahim A, Rockey DC. Lactulose-induced hypernatremia in cirrhotic patients with hepatic encephalopathy. J Clin Gastroenterol, 2025. Tier A, observational. DOI 10.1097/mcg.0000000000002230; PMID 41525261. — 6,742 hospitalized cirrhosis patients, 1,651 with HE, 106 hypernatremic. Abstract only, from OpenAlex reconstructed text.Full text could not be opened (publisher page returned HTTP 402). Cirrhosis with HE cohort: hepatic disease confounds.
  12. Merli M, Caschera M, Piat C, Pinto G, Diofebi M, Riggio O. The effect of lactulose and lactitol administration on fecal fat excretion in patients with liver cirrhosis. J Clin Gastroenterol, 1992. Tier A for steatorrhea outcome only. DOI 10.1097/00004836-199209000-00009; PMID 1401823. — n=18, Child-Pugh A or B, lactulose or lactitol arms. Abstract from OpenAlex.Mixed lactulose and lactitol cohort; no vitamin measured; cirrhosis confounds.
  13. Nagendra R, Viswanatha S, Chidambara Murthy KN, Venkat Rao S. Effect of incorporating lactulose in infant formula on absorption and retention of nitrogen, calcium, phosphorus and iron in rats. Int Dairy J, 1994. Tier B, rat. DOI 10.1016/0958-6946(94)90007-8. — Weanling rats, 0.5-1.0% lactulose in formula, five weeks. Abstract on ScienceDirect (via summarizing fetch tool); OpenAlex had no abstract; animal number not stated in it.
  14. Beynen AC, Kappert HJ, Yu S. Dietary lactulose decreases apparent nitrogen absorption and increases apparent calcium and magnesium absorption in healthy dogs. J Anim Physiol Anim Nutr, 2001. Tier B, dog. DOI 10.1046/j.1439-0396.2001.00301.x. — n=6 dogs, 3x3 Latin square. Abstract from OpenAlex.
  15. Yogappanavar SH. A study on serum zinc levels with stage of hepatic encephalopathy in chronic liver disease patients. J Contemp Clin Pract, 2023. Tier C context (lactulose use not reported in abstract). DOI 10.61336/jccp.2023.1086. — Cross-sectional, n=30. Abstract from OpenAlex.Lactulose not isolated as an exposure; indication-linked finding only.
  16. Almansouri M, Arif RH, Fallatah A, et al. Efficacy of zinc and lactulose vs. lactulose monotherapy in improving cognitive function and serum ammonia levels in cirrhotic patients with minimal hepatic encephalopathy. Clin Exp Hepatol, 2025. DOI 10.5114/ceh.2025.154666; PMID 42022367. — Abstract only, from OpenAlex. Reports p=0.104 for the benefit while concluding benefit; no lactulose effect on zinc measured.Zinc supplementation trial; used as context only and not as evidence for any grade.
  17. D'Aimmo MR, Mattarelli P, Biavati B, Carlsson NG, Andlid TA. The potential of bifidobacteria as a source of natural folate. J Appl Microbiol, 2012. In vitro, no lactulose. DOI 10.1111/j.1365-2672.2012.05261.x. — 19 bifidobacterial strains; 10 folate-autotrophic. Abstract from OpenAlex.Cohort excluded lactulose. Not Tier B or C for this drug; supports no grade.
  18. PubMed search listing "lactulose prebiotic bifidobacteria" (18 records), PubMed, 2026-10-04. Search channel record, not evidence. — Used to locate [5], [6] and [7]; listing text read through a summarizing fetch tool.
  19. Lactulose side effects, Drugs.com. Drug-reference text derived from labeling; corroborates the label only. — Sentences on severe diarrhea leading to hypovolemia, hypokalemia and hypernatremia; hyperchloremic metabolic acidosis. Read through a summarizing fetch tool. The Drugs.com professional monograph URL for lactulose returned HTTP 404.Not independent of the label; supports nothing alone.
  20. Top 10 medications that deplete the body of essential nutrients, YK Nutrition consultations (2016). Tier D. — Source of the claim that mineral oil, lactulose (Enulose), MiraLAX and senna deplete vitamins A, D, E, K, B12, calcium, iron and zinc; no citations. Read through a summarizing fetch tool.Tier D: claim origin only, supports nothing.
  21. Medication-induced nutrient depletion, Riordan Clinic handout. Tier D. — Opened to check for a lactulose entry: its only laxative row is bisacodyl; lactulose is not listed.Tier D: lists no lactulose claim; supports nothing.
  22. Xie XL, Zhou WT, Zhang KK, Chen LJ, Wang Q. METH-induced neurotoxicity is alleviated by lactulose pretreatment through suppressing oxidative stress and neuroinflammation in rat striatum. Front Neurosci, 2018. Tier B, rat. DOI 10.3389/fnins.2018.00802; PMID 30450033. — n=18 male Sprague Dawley rats (6 per group); lactulose 5.3 g/kg oral gavage every 12 hours; ROS and MDA measured. Abstract opened via OpenAlex; Methods opened on the Frontiers page via a summarizing fetch tool. No lactulose-alone group.
  23. Alexandrescu L, Tofolean IT, Aftenie C, et al. Lactulose, rifaximin, and survival in hepatic encephalopathy: a cohort study of 120 patients. J Clin Med, 2025. Tier C context (lactulose not isolated for hemoglobin). DOI 10.3390/jcm14207331; PMID 41156201. — Retrospective cohort, n=120 cirrhosis with HE; mean hemoglobin 9.35 g/dL; lactulose in 63.3%. Abstract only, opened via OpenAlex. Full text (MDPI PDF link listed) was not opened.Hepatic disease confounds; no hemoglobin comparison by lactulose use in the abstract.
  24. Wen J, Liu Q, Song J, Tong MH, Peng L, Liang H. Lactulose is highly potential in prophylaxis of hepatic encephalopathy in patients with cirrhosis and upper gastrointestinal bleeding: results of a controlled randomized trial. Digestion, 2013. Tier A for the HE prophylaxis outcome; hemoglobin used only as a baseline predictor. DOI 10.1159/000346083; PMID 23485720. — RCT, n=128 (lactulose n=63, none n=65), 6 days. Abstract opened via OpenAlex.Hemoglobin is a prognostic variable here, not a lactulose outcome. Cirrhosis with GI bleeding confounds.
  25. PubMed search listings "lactulose oxidative stress rats" and "lactulose hemoglobin hepatic encephalopathy", PubMed, 2026-10-04. Search channel record, not evidence. — Used to locate [22], [23] and [24] and the unopened Yu 2015 lead; listing text read through a summarizing fetch tool.