Dicyclomine

Also sold as Bentyl, Byclomine, Dibent.

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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.

Dicyclomine has no classical depletion machinery on the regulatory label. The label states that "the metabolism of dicyclomine was not studied," contains no statement of CYP450 induction or inhibition in the sections read, and reports urinary excretion of 79.5% of the dose and fecal excretion of 8.4%, with a mean plasma half-life of about 1.8 hours in one study [1]. No retrieved study measured a vitamin, mineral or physiological marker in people taking dicyclomine. The red and orange tiers are therefore empty, and that is the finding, not a gap in effort.

ATC A03AA07 [2] · also sold as Bentyl and Byclomine and Dibent [1][3] · 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 Dicyclomine 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

Antacid co-use: timing interaction, direction is antacid affecting the drug

Yellow — Low

See study details

Antacids may reduce dicyclomine absorption; this is not a depletion of any nutrient by dicyclomine.

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

Null or negative: None applicable; no separation interval is published in the sections read.
At-risk subgroups: People who take antacids regularly.
Counter-evidence: None retrieved.

Regulatory status

Label, section 7: "Because antacids may interfere with the absorption of anticholinergic agents including dicyclomine hydrochloride, simultaneous use of these drugs should be avoided." [1]

Population evidence

Label statement only; no study, magnitude or separation interval is given in the label text read. The label does not name the antacid minerals.

Mechanism

Not described in the label text read.

Counter-evidence held on record

Direction check (Hard Rule 4): the antacid affects the drug. Ask a pharmacist for a separation interval; none is stated in the label text read and none is invented here.

Riboflavin (vitamin B2): class extrapolation, reverse direction, test-dose absorption

Yellow — Low

See study details

CLASS EXTRAPOLATION: a different antimuscarinic (propantheline) raised the amount of an oral riboflavin test dose absorbed while delaying it; dicyclomine was not studied.

Full detail and limits

Limits on what this shows

Null or negative: No dicyclomine riboflavin study located; PubMed listings for dicyclomine with vitamin terms returned only Bendectin-related literature [13].
At-risk subgroups: None.
Counter-evidence: Single-agent, single-nutrient, test-dose pharmacokinetic study; it does not show a change in riboflavin status.

Regulatory status

The label notes that anticholinergics may alter absorption of drugs through GI motility, with slowly dissolving digoxin as the example; riboflavin is not mentioned [1].

Population evidence

Tier C: Levy, Gibaldi and Procknal 1972, healthy adult males, propantheline bromide; abstract: the agent "delayed the absorption of the vitamin but caused a pronounced increase in the total amount absorbed" [5]. Number of subjects was not stated in the page read. A pharmacologic test dose was used; no dose is repeated here. Cohort test: dicyclomine was not in the cohort. The class label is defensible because propantheline is an antimuscarinic antispasmodic and dicyclomine shares the antimuscarinic action and, in rats, depressed gastric emptying [4]; dicyclomine also has a musculotropic action propantheline lacks.

Mechanism

Delayed gastric emptying and slower intestinal transit increasing contact time at the absorption site, as summarized from the abstract page [5].

Counter-evidence held on record

Excess or retention direction and a pharmacokinetic observation, not a deficiency. It implies no change in riboflavin intake; supplementation would not be the remedy.

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 evidence located that dicyclomine affects mitochondrial structure, membrane potential, electron transport or biogenesis.

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 evidence located for even a yellow grade, and no circulating consumer claim about dicyclomine and mitochondria found. The one dicyclomine cell/animal oxidative-stress paper [8] is abstract-level and reports no mitochondrial endpoint, so it is not carried into this entry (see overlap map). Classification: clean zero on the channels that worked, with a tooling caveat (direct APIs blocked, several listings rate-limited, queries combined). Not reassurance.

Channels tried

PubMed listing "dicyclomine AND (mitochondria* OR respiratory chain OR ATP OR membrane potential)": six records returned, none a dicyclomine mitochondrial study (all muscarinic M1 receptor pharmacology or unrelated gene-discovery papers) [13]. Crossref keyword search "dicyclomine mitochondrial": monographs and handbook entries only [17]. WebSearch "dicyclomine mitochondrial membrane potential mitochondrial toxicity": generic toxicology guides, no dicyclomine data. Europe PMC "dicyclomine AND (oxygen OR ATP OR copper)": 236 hits, top ten were case reports and unrelated papers. Repair-pass queries (PubMed listings, 2026-10-04): "dicyclomine Huntington" 0 records; "dicyclomine mutant huntingtin" 0 records; "dicycloverine mitochondria" 0 records; "dicyclomine neurons calcium" 3 records (PMID 25738989 anticholinergic neuronal/astrocyte in vitro model, PMID 10366013 M3 presynaptic receptors in rat dopamine neurons, PMID 7616431 guinea pig bladder presynaptic receptors), none a study of dicyclomine effects on mitochondria; "dicyclomine ATP" 3 records (PMIDs 2450199, 2844551, 12081652), all muscarinic M1/M2 receptor pharmacology in which ATP appears as a transmitter or a tool compound, none a dicyclomine energy-metabolism study [13]. Crossref keyword queries "dicyclomine mitochondrial function cells", "dicyclomine Huntington neuroprotective" and "dicyclomine hydrochloride neuroprotective effect": USP monographs, analytical, formulation and infantile colic papers only, no cell-level dicyclomine record [17]. Not reachable (HTTP 429, not retried): PubMed "dicyclomine mitochondrial" and "dicyclomine neuroprotection", Crossref "dicyclomine calcium signaling neurons", Europe PMC combined query, WebSearch (budget exhausted). Label: no mitochondrial statement [1]. Suggested cell-level literature (Huntington models, neuronal mitochondrial function) was searched for and not found; no such paper was opened, so none is cited.

Oxidative Stress

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

Oxidative stress: reverse direction, mouse model only

Yellow — Low

See study details

In one mouse model, dicyclomine at the highest dose enhanced antioxidant defense; no human redox marker has been measured, and no pro-oxidant effect was found.

Full detail and limits

Limits on what this shows

Null or negative: PubMed and Crossref listings for dicyclomine with oxidative stress terms returned no other drug-specific study [13][17].
At-risk subgroups: None.
Counter-evidence: Single animal study in a disease model, supra-therapeutic dose, not in the GI or IBS setting.

Regulatory status

The label contains no oxidative-stress statement [1].

Population evidence

Tier B: Sanawar 2022 gave dicyclomine at 40, 80 and 160 mg/kg for 21 days to mice (60 animals, six groups) in a haloperidol plus paraquat Parkinsonism model; the abstract reports that only 160 mg/kg prevented the induced parkinsonism "through enhancement of antioxidant defense system," with oxidative stress markers and neurotransmitters measured [8]. Specific markers and effect sizes were not available in the abstract-level read.

Mechanism

Attributed by the authors to antioxidant defense enhancement; the underlying route is not established here. The mouse dose is not translatable to the labeled human range of 80 to 160 mg/day [1].

Counter-evidence held on record

Reverse-direction finding: the drug's chemistry appears protective in this model, not antioxidant-depleting. This is not a reason to take antioxidant supplements, and not a claim that dicyclomine protects people.

Copper and Iron Balance

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

Iron: theoretical acid-dependent absorption route, no iron measured

Yellow — Low

See study details

Dicyclomine can reduce gastric acid output in animals and gastric acid supports non-heme iron absorption, but no study has measured iron status or absorption in dicyclomine users.

Full detail and limits

Limits on what this shows

Null or negative: The ODS fact sheet notes that prolonged PPI use does not deplete iron in people with normal stores [12]. The opposite transit effect is also documented for another antimuscarinic (see the riboflavin entry), so the net direction for iron is unknown [5]. PubMed search listings for dicyclomine with iron, ferritin, anemia and hemoglobin returned no relevant record [13].
At-risk subgroups: None defined by evidence.
Counter-evidence: Anemia or low ferritin in IBS patients has competing explanations (diet change, blood loss, coexisting disease); under Hard Rule 6 these are presumed before the drug.

Regulatory status

The label states that "the inhibiting effects of anticholinergic drugs on gastric hydrochloric acid secretion are antagonized by agents used to treat achlorhydria." It lists no iron or hematologic event among the reactions read [1].

Population evidence

None for iron in dicyclomine users. Tier B: in rats, orally dosed dicyclomine "depressed gastric emptying before gastric acid output," and subcutaneous dicyclomine depressed both at essentially equal doses (Brodie 1966, abstract-level read) [4]. The NIH Office of Dietary Supplements states that gastric acid plays an important role in non-heme iron absorption and that proton pump inhibitors can reduce iron absorption [12]; PPIs were not dicyclomine and are cited only for the acid-iron link, not extrapolated.

Mechanism

Named but unquantified: antimuscarinic reduction of gastric acid secretion. The size of the acid effect in humans at labeled doses was not found.

Counter-evidence held on record

Theoretical only. Do not add or change iron intake because of dicyclomine; iron supplementation carries its own risks and is a decision for a prescriber after testing. No dose is given.

Copper

Not graded — disclosed evidence gap

See study details

No evidence located that dicyclomine alters copper absorption, status or ceruloplasmin.

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 evidence and no circulating claim found. Classification: genuine gap on retrieved channels with a tooling caveat. Copper is kept separate from Iron.

Channels tried

PubMed listing "dicyclomine AND (iron OR ferritin OR anemia OR hemoglobin OR copper OR ceruloplasmin)": three records returned, none relevant (a JAMA diarrhea review, a cuproptosis gene-discovery paper, a plant antispasmodic study) [13]. Europe PMC with "copper": no relevant hit. WebSearch for dicyclomine with copper, iron and anemia: only interaction-checker and monograph pages. Repair-pass Crossref keyword query "dicyclomine copper ceruloplasmin": ten records, either copper/ceruloplasmin laboratory papers or USP dicyclomine monographs, no record linking the two [17]. Label: no copper statement [1]. No mechanism class in the screen (chelation, mucosal injury, enzyme induction) applies to copper.

Gut Microbiome Risk

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

Gut microbiome risk: unmeasured, in vitro antibacterial activity only

Yellow — Low

See study details

Dicyclomine inhibits some bacteria in vitro and slows GI function and saliva production by design; no study has measured the gut microbiome of dicyclomine users.

Full detail and limits

Limits on what this shows

Null or negative: The Maier 2018 screen of more than 1,000 marketed drugs against 40 gut strains does not name dicyclomine, antispasmodics or anticholinergics in the article text read; its supplementary tables were not opened, so inclusion is unknown [9]. Vich Vila 2020 analyzed 41 medication categories in 1,883 participants, including an IBS cohort of 305, with no antispasmodic category in the text read [10]. Absence from these papers is absence of data, not a null result.
At-risk subgroups: None defined by evidence.
Counter-evidence: Confounding by indication is presumed: users have functional bowel disease, and no retrieved study separates the underlying condition from the drug. In vitro inhibitory concentrations are not shown to occur in vivo.

Regulatory status

The label contains no microbiome statement. It documents dry mouth (33% in the trial table) and postmarketing constipation [1].

Population evidence

None for gut microbiome in humans taking dicyclomine. Tier B, dicyclomine itself: Karak 2003 reported minimum inhibitory concentrations of 10 to 100 microg/ml, bacteriostatic action against Shigella dysenteriae 7, bactericidal action against Staphylococcus aureus strains, and protection of mice challenged with Salmonella typhimurium at 30 to 60 microg per dose [6]. Karak 2004 reported rapid killing of Gram-positive organisms and a bacteriostatic effect on Shigella boydii and S. typhimurium [7]. Both are abstract-level reads. Tier C context: a cross-sectional NHANES 2009 to 2012 analysis (n = 1,596 adults aged 55 to 69) found anticholinergic burden scores inversely associated with oral microbiome alpha diversity [11]; this is the oral, not gut, microbiome, uses burden scales, and did not isolate dicyclomine, so it does not pass the cohort test and carries no weight in the grade.

Mechanism

Three candidate routes, none tested in people: (a) direct antibacterial action [6][7]; (b) reduced salivary secretion (dry mouth 33%) [1]; (c) slowed GI transit, which is the drug's intended antimuscarinic effect and is not itself a nutrient finding. No source on transit and microbiome composition was retrieved, so route (c) is an untested hypothesis. Whether luminal concentrations at labeled doses approach the in vitro inhibitory range was not established by either study.

Counter-evidence held on record

Not a deficiency claim and not a statement that dicyclomine alters the gut microbiome. No probiotic or supplement is implied.

Oxygen and ATP Output

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

Oxygen delivery/utilization

Not graded — disclosed evidence gap

See study details

No evidence located that dicyclomine alters hemoglobin, red-cell mass or tissue oxygen delivery.

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 evidence and no circulating claim found. Hard Rule 2 note: palpitations and tachyarrhythmias listed postmarketing [1] are cardiac adverse events of the drug's antimuscarinic pharmacology, not an oxygen-delivery finding. Classification: genuine gap on retrieved channels with a tooling caveat.

Channels tried

PubMed listing "dicyclomine AND (hypoxia OR erythrocyte OR oxygen consumption OR oxygen delivery OR hematocrit)": zero results reported [13]. The iron/hemoglobin listing above returned nothing relevant. Europe PMC "dicyclomine AND (oxygen ...)": no relevant hit. Repair pass: PubMed listing "dicyclomine hypoxia" returned an unrendered page (no information); PubMed "dicyclomine hemoglobin" and Crossref queries for dicyclomine with anemia, hemoglobin, red blood cell, methemoglobinemia and hemolytic anemia were refused with HTTP 429 and not retried, so those angles are untested rather than null [13][17]. Label adverse-reaction lists read contain no anemia or hematologic event [1], which is not evidence of absence.

ATP production

Not graded — disclosed evidence gap

See study details

No evidence located that dicyclomine alters mitochondrial ATP synthesis or cellular energy output.

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 evidence and no circulating claim found. Hard Rule 2 note: asthenia (7%), somnolence (9%) and postmarketing fatigue and malaise [1] are symptoms of the drug's central and peripheral antimuscarinic effects and are not filed as an energy-metabolism finding. Classification: genuine gap on retrieved channels with a tooling caveat. Kept separate from Mitochondrial burden and Oxygen delivery/utilization; the shared null search is disclosed in the overlap map.

Channels tried

Same PubMed mitochondria/ATP listing as above (no relevant record) [13]; Crossref keyword searches [17]; Europe PMC "dicyclomine AND (oxygen OR ATP OR copper)" (no relevant hit); repair-pass PubMed listing "dicyclomine ATP" returned three M1/M2 muscarinic receptor pharmacology records in which ATP is a transmitter or tool compound (PMIDs 2450199, 2844551, 12081652), none a dicyclomine study of cellular energy output [13]; WebSearch for dicyclomine with ATP, mitochondria and oxidative terms returned supplement-marketing pages with no dicyclomine data (Tier D, not cited).

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.

Vitamin B6 (pyridoxine) involvement with dicyclomine
Where it comes from: A PubMed listing for "dicyclomine vitamin" returned 205 records, and the 20 shown were Bendectin/Debendox pregnancy-nausea literature; Crossref also lists adverse-reaction entries titled "Dicyclomine-doxylamine-pyridoxine" (titles only read) [13][17].
Why it fails: Pyridoxine was an ingredient of a combination product, not a nutrient affected by dicyclomine. No record read reports a pyridoxine level or depletion. A retrieval conflation, listed so it is not mistaken for a depletion signal. Dicyclomine's own label has no B6 statement [1].
Any nutrient or category depletion attributed to dicyclomine or anticholinergics in generic depletion charts
Where it comes from: Searched: a chiro.org drug-nutrient depletion chart page and a Zenodo review titled "Drug-Induced Nutrient Depletion" (both Tier D), plus a Drugs.com interaction checker page for dicyclomine with vitamin B12 [14][15][16].
Why it fails: No dicyclomine-specific claim was located: the chart page lists neither dicyclomine nor antispasmodics, the review's drug list omits anticholinergics, and the interaction checker reports no interaction with vitamin B12. There is nothing to rebut; this row discloses the null audit. The WebSearch budget ended before every consumer source could be scanned.

How the body handles this medication

Metabolism and enzymes: "The metabolism of dicyclomine was not studied." No CYP450 inhibition or induction statement appears in the label sections read. Prior plausibility of enzyme-driven catabolism of any nutrient: no mechanism named.[1] DailyMed label, section 12.3
Elimination: Principal route is urine (79.5% of the dose); feces 8.4%. Mean plasma half-life about 1.8 hours in one study.[1] DailyMed label, section 12.3
Absorption: Rapidly absorbed after oral dosing, peak values within 60 to 90 minutes. No named transporter or site-specific absorption mechanism is described in the label.[1] DailyMed label, section 12.3
Mechanism of action: Specific antimuscarinic effect at acetylcholine receptor sites plus a direct musculotropic effect on smooth muscle. This is the intended pharmacology and is not graded as a nutrient finding.[1] DailyMed label, section 12.1
Interactions with absorption: Antacids may interfere with absorption of dicyclomine, so simultaneous use is to be avoided (direction: antacid affects drug). Anticholinergics may alter absorption of slowly dissolving digoxin forms through motility. Inhibition of gastric hydrochloric acid secretion by anticholinergics is antagonized by agents used to treat achlorhydria. No renal tubular water or electrolyte effect is described.[1] DailyMed label, section 7
Renal and hepatic impairment, adverse reactions: Use with caution in hepatic and renal impairment; renal impairment effects on pharmacokinetics were not studied. Trial table: dry mouth 33%, dizziness 40%, blurred vision 27%, nausea 14%, somnolence 9%, asthenia 7%, nervousness 6%. Postmarketing events include constipation, fatigue and palpitations; no hematologic event appears in the list read. Label revision shown: 10/2014.[1] DailyMed label, sections 6 and 8

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
No routine nutrient lab is supported
No dicyclomine-specific evidence supports routine iron, B vitamin, copper or oxidative-stress testing. If a result is low for another reason, do not attribute it to dicyclomine without ruling out the underlying bowel condition, diet and blood loss (Hard Rule 6).
Timing
Antacids
The label says to avoid simultaneous use of antacids and dicyclomine. It gives no interval; ask a pharmacist. No other nutrient or supplement separation interval is stated for dicyclomine in the label text read [1].
Symptom
Dry mouth and constipation
Dry mouth (33% in the trial table) and constipation are expected antimuscarinic effects [1]. Report persistent symptoms to the prescriber; they are not nutrient deficiencies.
At-risk groups
Impairment, age, pregnancy, infants
Use with caution in renal and hepatic impairment and in older adults (low-end dosing). Adequate pregnancy studies at 80 to 160 mg/day have not been done. The label contraindicates use in infants under 6 months and in nursing mothers [1].
Co-medication
Digoxin and other anticholinergics
Serum digoxin may rise with slowly dissolving forms; other anticholinergic drugs add to effects [1]. Not nutrient findings.
Recheck
Ungraded categories
Mitochondrial burden, Copper, Oxygen delivery/utilization and ATP production should be re-searched when PubMed, Crossref, Europe PMC and OpenAlex API access is available, including cell-level work on calcium signaling, neuroprotection and mitochondrial function, which could not be retrieved in the repair pass.

Overlap map, to prevent double counting

Entries that rest on the same underlying source or mechanism are not independent confirmation.

Iron
Shares evidence with: Gut microbiome risk; Riboflavin; Antacid co-use
Note: All draw on the same label section 7 and on the shared antimuscarinic GI-secretion and transit mechanism. Brodie 1966 [4] informs Iron and, through gastric emptying, the Riboflavin cohort-test justification. Count as one mechanism, not several lines of evidence.
Riboflavin
Shares evidence with: Iron; Gut microbiome risk
Note: Levy 1972 [5] is the sole source for Riboflavin and supplies the opposing-direction note in Iron. It is a propantheline study.
Gut microbiome risk
Shares evidence with: Oxidative stress (no shared source); Karak 2003 and 2004
Note: Karak 2003 [6] and 2004 [7] are two papers from the same research group on one compound and overlapping organisms; treat as one line of in vitro evidence.
Mitochondrial burden
Shares evidence with: ATP production; Oxygen delivery/utilization; Copper; Iron
Note: No evidence exists in any of these entries. The same combined PubMed, Crossref and Europe PMC searches support the null for several; they are one search effort, not four independent nulls. Copper and Iron share a single PubMed query.
Oxidative stress
Shares evidence with: None
Note: Rests solely on Sanawar 2022 [8]; it does not support the Mitochondrial burden or ATP entries.

All references used above

Dicyclomine

Findings for this medication

What the research found

Antacid co-use: timing interaction, direction is antacid affecting the drug

Riboflavin (vitamin B2): class extrapolation, reverse direction, test-dose absorption

The five body-system areas

⚡Mitochondrial Burden

Mitochondrial burden

💥Oxidative Stress

Oxidative stress: reverse direction, mouse model only

⚖️Copper and Iron Balance

Iron: theoretical acid-dependent absorption route, no iron measured

Copper

🌿Gut Microbiome Risk

Gut microbiome risk: unmeasured, in vitro antibacterial activity only

💨Oxygen and ATP Output

Oxygen delivery/utilization

ATP production

Claims checked and not supported

Vitamin B6 (pyridoxine) involvement with dicyclomine

Any nutrient or category depletion attributed to dicyclomine or anticholinergics in generic depletion charts

How the body handles this medication

What the research says is worth watching

Overlap map, to prevent double counting

Mitochondrial Burden

Oxidative Stress

Copper and Iron Balance

Gut Microbiome Risk

Oxygen and ATP Output