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MyDeficiencies

Fexofenadine

second-generation H1 receptor antagonist

Also sold as Allegra.

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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.

Fexofenadine has no classical depletion machinery. About 5% of a dose is metabolized, roughly 80% is recovered in feces and about 11% in urine, it is not described as inducing or inhibiting any CYP enzyme in the label text retrieved, and its label contains no statement about any vitamin, mineral or other nutrient losing ground on the drug [1][2][3][4]. Every mechanism class for a drug-to-nutrient effect (hepatic induction, renal wasting, cofactor antagonism, hormonal or dilutional disturbance, appetite or sedation-driven intake change) is absent in the sources opened. Sedation is minimal, so a changed-intake pathway has no documented footing either [3].

second-generation H1 receptor antagonist · ATC R06AX26 (per Wikipedia citing WHO; WHO index not opened [5]) · also sold as Allegra and Allegra-D (with pseudoephedrine) and Children's Allegra; many OTC generics · reviewed 2026-10-07. 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 Fexofenadine 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

Fruit juice (grapefruit, orange, apple): nutrient-to-drug absorption interaction, not a depletion

Yellow — Low

See study details

Juice lowers fexofenadine absorption by inhibiting intestinal OATP uptake. The drug does not deplete anything here; the beverage lowers drug exposure, so the remedy is timing and taking the tablet with water.

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 and counter findings: Kharasch 2005 [10] has a wide CI that spans no effect (0.59 to 1.04), so the effect with orange and apple juice after a meal is smaller and less certain than the large 60% to 70% reductions in fasting crossover work. Reductions vary between individuals (Dresser 2005 reports variability falling about 2-fold with juice [7]).
  • At-risk subgroups: People who take the tablet with juice daily; large juice volumes (the 1200 mL arm gave the largest reduction).

Direction

Nutrient (juice flavonoids such as naringin) to drug. Reduced drug exposure. Not a depletion, retention or excess of any nutrient (Hard Rule 4).

Regulatory status

Labeled. OTC Drug Facts: "do not take with fruit juices (see Directions)" [1][2]. PI as reproduced on Drugs.com (rev 3/2012): grapefruit, orange and apple juice may reduce absorption, estimated bioavailability reduction 36%, take tablets with water [3].

Population evidence

Dresser 2002 [6]: randomized 5-way crossover, n=10 healthy adults, 120 mg fexofenadine; grapefruit, orange and apple juices reduced AUC, Cmax and urinary excretion to roughly 30% to 40% of the water control; half-life and renal clearance unchanged (abstract via OpenAlex summary; CI not given). Dresser 2005 [7]: randomized 4-way crossover, n=12; 300 mL grapefruit juice gave AUC 58% and Cmax 53% of water (P <.001), 1200 mL gave 36% and 33%. Won 2013 [8]: n=18, 240 mL grapefruit juice or furanocoumarin-free juice, both lowered AUC and Cmax by about 25% (P ≤.008), half-life unchanged. Akamine 2015 [9]: n=14, AUC0-24 of (R)-fexofenadine down 39% and (S) down 52%. Kharasch 2005 [10]: crossover with fexofenadine taken after a meal with orange or apple juice, AUC ratio 0.73 (90% CI 0.59 to 1.04), versus 0.91 (90% CI 0.70 to 1.35) without juice.

Mechanism

Named. Inhibition of intestinal OATP1A2 (and OATP2B1) uptake; naringin is a major causal constituent; furanocoumarins and polymethoxyflavones are not the major mediators [7][8][11][12]. CYP3A4 is not the route, so the interaction runs opposite to the usual grapefruit rule.

Timing

A review reports the inhibitory effect lasted more than 2 hours but less than 4 hours, so spacing is feasible [11]; another review advises at least 4 hours between juice and OATP-dependent medicines [24]. Glaeser 2007 [12] found juice given with, or 2 hours before, the drug still reduced exposure. The label itself says only to take with water.

Counter-evidence held on record

Why not a higher grade The evidence base is Tier A and replicated, but red and orange encode a drug causing a nutrient deficit. Here a beverage lowers drug exposure, so the entry is a context flag capped at yellow. Framing caution This is not a vitamin or mineral deficiency. No supplement is implied. The practical point is to take fexofenadine with water, not juice.

Aluminum and magnesium antacids: mineral-to-drug timing interaction, not a depletion

Yellow — Low

See study details

Antacids containing aluminum or magnesium lower fexofenadine absorption when taken close together; fexofenadine does not alter aluminum or magnesium status in any source retrieved.

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 and counter findings: None found. A second independent trial was not located. Note that the interaction runs from antacid to drug, so even two trials would leave this a Hard Rule 4 timing entry capped at yellow, not a depletion grade.
  • At-risk subgroups: People using over-the-counter antacids for heartburn at the same time as the tablet.

Direction

Antacid (mineral hydroxides) to drug. Reduced drug exposure. Not a depletion.

Regulatory status

Labeled in US, UK and Indian regulatory texts (the US texts share one underlying label). OTC Drug Facts: "do not take at the same time as aluminum or magnesium antacids" [1][2]. PI as reproduced on Drugs.com: fexofenadine "should not be taken closely in time with aluminum and magnesium containing antacids"; taken within 15 minutes of Maalox, AUC fell by 41% [3]. Current US Rx label text (Section 7.1, via a label library page opened 2026-10-08): 120 mg (2 x 60 mg capsule) within 15 minutes of Maalox "decreased fexofenadine AUC by 41% and Cmax by 43%", in "healthy adult subjects"; no sample size or design is given [28]. UK SPC (Xadine): an aluminium and magnesium hydroxide gel antacid 15 minutes before fexofenadine reduced bioavailability, "most likely due to binding in the gastrointestinal tract", with advice to leave 2 hours between the two; no study is cited [29]. Sanofi India PI repeats the 15-minute finding and the 2-hour gap, with no sample size [30].

Population evidence

The 41% AUC and 43% Cmax reductions come from label text only [3][28]; the primary study, its sample size and CI were not located after a second pass on 2026-10-08. Channels tried: label pages (US label library, UK SPC, Indian PI, Drugs.com) all state the result without citing the study; the 2024 MDPI systematic review of fexofenadine pharmacokinetics was opened and does not cover antacids [35]; a PubMed listing for fexofenadine AND (magnesium OR calcium OR antacid) returned 33 records, of which the first 10 (relevance order) were read and none was an antacid pharmacokinetic study [37]; OpenAlex search, Europe PMC and the FDA biopharmaceutics review URL were rate-limited, 404 or blocked. Effect size therefore stays at the label value without CI, and a second independent Tier A source was not found.

Mechanism

Regulator-stated but not verified from a primary study: the UK SPC says the reduction is "most likely due to binding in the gastrointestinal tract" [29]; Wikipedia, citing a chemistry paper that was not opened, attributes it to metal complex formation, not a pH effect [5]. Treat the mechanism as probable, not demonstrated.

Counter-evidence held on record

Framing caution This is a timing interaction. It does not mean aluminum or magnesium status changes, and nothing here suggests adding any mineral. The UK SPC and Indian PI give a 2-hour separation interval [29][30]; the US label gives none beyond "not closely in time".

Green tea catechins (EGCG): nutrient-to-drug absorption interaction, single small crossover trial

Yellow — Low

See study details

Green tea extract at about 300 mg EGCG cut fexofenadine AUC by 70% in 10 volunteers, by OATP1A2 inhibition; this is drug exposure falling, not a nutrient deficit.

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 and counter findings: Not all co-ingested nutrients matter: a crossover study in 10 volunteers found no major effect of vitamin D3 on fexofenadine pharmacokinetics (AUC0-2h geometric mean ratio 1.429, 90% CI 0.890 to 2.294) or on duodenal OATP1A2 mRNA [14]. No second green tea study was found.

Direction

Food component to drug. Reduced drug exposure. Not a depletion.

Regulatory status

Not mentioned in the labels retrieved [1][2][3].

Population evidence

Misaka 2022 [13]: randomized open-label two-phase crossover, 10 healthy Japanese volunteers, fexofenadine 60 mg with pseudoephedrine 120 mg given with aqueous green tea extract (about 300 mg EGCG) or water. Fexofenadine AUC fell 70% and 24-hour urinary excretion fell 67% (both P < 0.001); Tmax and half-life unchanged; pseudoephedrine unaffected. CIs not reported in the abstract (OpenAlex record).

Mechanism

Named in vitro: EGCG (100 and 1,000 micromolar) and the extract inhibited OATP1A2-mediated fexofenadine uptake in HEK293 cells [13].

Counter-evidence held on record

Framing caution A single study of 10 people with a large effect. It describes a beverage-drug interaction and no change in any nutrient. It supports no supplement advice.

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: in vitro membrane depolarization at 150 to 400 micromolar

Yellow — Low

See study details

Fexofenadine depolarized mitochondria in two cancer cell lines at concentrations far above those the cell-line paper considers clinical; another cell study found little effect.

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 and counter findings: Wang 2014 [17] reported that terfenadine, not fexofenadine, caused mitochondrial membrane potential loss in prostate cancer lines; fexofenadine had "little effect" in the proliferation assay. De Melo Mendes 2019 [27] found fexofenadine inactive against Leishmania, unlike other antihistamines that depolarized parasite mitochondria. In both studies the comparator or sibling compounds, not fexofenadine, produced the mitochondrial effect.

Direction

Drug effect on organelle function in vitro. Not a nutrient entry.

Regulatory status

No mitochondrial statement in the labels retrieved [1][2][3].

Population evidence

Trybus 2026 [16] (full article page read via summarizing fetch): fexofenadine caused mitochondrial membrane depolarization, Bcl-2 inactivation, caspase-3/7 activation and apoptosis in HeLa and A549 cells, using a commercial membrane potential kit; Beas-2B cells were less sensitive (200 micromolar: 18.5% Annexin V-positive versus 49.6% HeLa and 37.07% A549). ATP and oxygen consumption were not reported.

Mechanism

ROS-dependent mitochondrial dysfunction in vitro; N-acetylcysteine reduced the effects [16].

Counter-evidence held on record

Framing caution Cell-line concentrations of 150 to 400 micromolar are not a statement about people taking 60 to 180 mg tablets. No clinical mitochondrial finding exists in what was retrieved.

Oxidative Stress

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

Oxidative stress: pro-oxidant signal in animal and in vitro data at supra-clinical exposure

Yellow — Low

See study details

Fexofenadine raised an oxidant marker in a small rat study and induced reactive oxygen species in cancer cell lines at 150 to 400 micromolar; no human redox marker or antioxidant nutrient was measured.

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 and counter findings: No human study measuring MDA, glutathione, SOD or antioxidant capacity in fexofenadine-treated people was located. Non-tumorigenic Beas-2B cells were less sensitive (viability above 80% at 200 micromolar) [16].

Direction

Drug-induced oxidant burden (excess), a toxicity signal in non-human systems. Not a nutrient deficiency (Hard Rule 2) and not an antioxidant depletion, since no antioxidant nutrient was measured.

Regulatory status

No oxidative stress statement in the labels retrieved [1][2][3].

Population evidence

Tier B only. Mahmood 2024 [15]: 30 adult male albino rats in groups of 10 (control, 5 mg/kg/day, 10 mg/kg/day); at 10 mg/kg/day serum thioredoxin reductase and malondialdehyde were significantly higher than control (P < 0.05), with salivary gland acinar degeneration (OpenAlex abstract; a PubMed-listing summary stated both treated groups were raised, so the more conservative reading is used). Trybus 2026 [16]: HeLa, A549 and non-tumorigenic Beas-2B cells, fexofenadine 150 to 400 micromolar for 48 hours, concentration-dependent ROS accumulation reversed by N-acetylcysteine 5 mM; MTT IC50 about 211 (HeLa), 293 (A549) and 391 (Beas-2B) micromolar.

Mechanism

Named in vitro only: ROS accumulation linked to mitochondrial depolarization [16]. Human-equivalent exposure for the rat doses was not assessed in the abstract; the in vitro paper itself notes such concentration ranges exceed clinically achieved plasma levels.

Counter-evidence held on record

Framing caution Not evidence of oxidative stress or antioxidant loss in people taking standard doses. No antioxidant supplement is implied.

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 evidence was found that fexofenadine changes copper absorption, excretion or status.

Full detail, limits and 1 references

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 supports even a yellow grade, and no circulating copper claim for fexofenadine was found to rebut. A disclosed gap, not a finding of safety. Metal complexation of aluminum or magnesium (see antacid entry) is not copper evidence.

What was searched

PubMed listing "fexofenadine AND (copper OR zinc OR selenium)": 5 records. None measured copper status. One was a materials study of expired fexofenadine as a corrosion inhibitor on metallic copper in 1.0 M HCl (not biological; PMID 42156540, not used as evidence [21]); others concerned zinc sulphate as an erythropoietic protoporphyria treatment (fexofenadine had no significant effect) and a mouse diet low in magnesium and zinc [23]. DailyMed labels and the PI text contain no copper statement.

Channel outcomes

PubMed listing opened with several phrasings; OpenAlex and Crossref intermittently returned 429; a Crossref lookup of the metal-complex chemistry paper was rate-limited and not opened. Repair pass 2026-10-08: WebSearch for fexofenadine with serum copper, ceruloplasmin, serum iron or ferritin returned only unrelated pages; the US label library pages (Sections 6 and 7) and the UK SPC contain no copper statement [28][29]; the 2024 MDPI pharmacokinetics review does not mention copper [35]. Mixed result: a clean zero on PubMed plus partial tooling limitation.

Iron

Not graded — disclosed evidence gap

See study details

No evidence was found that fexofenadine changes iron absorption or status.

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 for an iron effect, and no circulating iron claim found. Not reworded as reassurance. Kept separate from Copper per Hard Rule 7.

What was searched

PubMed listing "fexofenadine AND (iron OR ferritin OR anemia)": 3 records, none showing an iron effect. One case report (single 35-year-old man, new restless legs syndrome after one month of fexofenadine 180 mg daily, resolving on stopping) recorded iron indices as unremarkable [19]. That is one patient, a null for iron, and not a basis for a grade. The other records were a juice review that named iron only in unrelated drug pairs and a snow contamination study.

Channel outcomes

One combined PubMed query was rate-limited twice; a narrower phrasing succeeded. Case report read as abstract only. Repair pass 2026-10-08: a WebSearch for fexofenadine with anemia, iron deficiency, low ferritin or red blood cell returned the same restless legs case report and no cohort or trial; the PMC full text of that case (PMC12852044) returned a reCAPTCHA interstitial and could not be opened, so its iron values stay at abstract level; the 2001 UK prescription-event monitoring cohort of fexofenadine (Craig-McFeely, Eur J Clin Pharmacol 2001, about 18,000 returned questionnaires) was opened as abstract only and reports adverse-event counts, not iron measures [34]. Tooling-limited in part, with a likely thin literature.

Gut Microbiome Risk

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

Gut microbiome risk: in vitro, reverse direction (growth-supporting for lactobacilli)

Yellow — Low

See study details

In bacterial culture, fexofenadine supported growth of most gut species tested and raised short-chain fatty acid output, the opposite of a dysbiosis signal; no human microbiome data with fexofenadine exposure were found.

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 and counter findings: No human 16S or fecal microbiota study of fexofenadine users was located. A lupus fecal-metabolite study that detected fexofenadine as a metabolite (PMID 36506019, same listing as [20]) was an unrelated disease cohort and gives no exposure-effect data.

Direction

Reverse or neutral (growth-supporting) in vitro. Not a risk signal as published.

Regulatory status

Not mentioned in the labels retrieved [1][2][3].

Population evidence

Hammouda 2025 [18]: in vitro culture of B. longum, L. reuteri, Bacteroides fragilis and E. coli at intestinal concentrations. Fexofenadine promoted growth of all species except B. longum, reduced biofilm formation in biofilm-forming species, enhanced biofilm in B. longum and L. reuteri co-culture, and increased lactic and propionic acid, with a significant rise in acetic acid (P < 0.05). Desloratadine and cyproheptadine inhibited growth of all tested bacteria. Abstract via OpenAlex; no human or animal cohort.

Mechanism

Named in the paper as altered cell surface hydrophobicity and adherence; not verified in vivo. The aggregator record also lists intestinal microflora among minor metabolic routes [4].

Counter-evidence held on record

Framing caution A culture-dish result, not evidence that fexofenadine changes the gut microbiome in people in either direction. No probiotic recommendation follows.

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 was found that fexofenadine alters hemoglobin, red-cell mass, hemolysis, methemoglobin 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 oxygen-carrying claim found. Any anemia effect would run through the Iron entry and is not double-counted (Overlap map).

What was searched

PubMed listing "fexofenadine AND (hemolysis OR methemoglobin OR hemoglobin OR red blood cell OR hematocrit)": 2 records. One was a renal transplant study in which fexofenadine served as a P-glycoprotein probe and hematocrit predicted tacrolimus clearance; fexofenadine was not reported to change hematocrit [26]. The other was a rat catheter study that did not name fexofenadine as given. The RxList page lists no hematologic adverse reactions [22]; the PI as reproduced lists headache, back pain and dizziness as common [3]. Repair pass 2026-10-08, counter-evidence recorded: the current US label (Section 6.1) states the frequency and magnitude of laboratory abnormalities were similar between fexofenadine and placebo, with no hematologic reaction named [28][32]; a Sanofi trial summary of a phase IIIa randomized, double-blind, placebo-controlled study of fexofenadine 180 mg once daily for 28 days in chronic idiopathic urticaria (259 randomized: 167 fexofenadine, 92 placebo) states laboratory tests "including hematologic analysis" showed "no clinically relevant changes from baseline to the end of treatment" in either group, with no hemoglobin value reported [31]. These are Tier A nulls with a hematologic panel measured but unitemized; they are not Tier B or C support for a grade and do not reach a graded entry.

Channel outcomes

Second PubMed listing with the same terms (iron, anemia) also negative. Repair pass 2026-10-08: WebSearch for fexofenadine with methemoglobinemia, hemolytic anemia or hemolysis returned only case reports of other causes (G6PD deficiency, infection, cefoxitin) and no fexofenadine record; PubMed listings for further phrasings were rate-limited. The circulating-claim audit now includes two depletion references that list no fexofenadine entry [33]. Tooling-limited in part.

ATP production

Not graded — disclosed evidence gap

See study details

No evidence was found that fexofenadine changes cellular ATP synthesis or 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 source measured ATP, and no circulating "low energy from fexofenadine" claim was found to rebut. Fexofenadine is a minimally sedating antihistamine, but fatigue as an adverse event is an outcome, not an ATP measurement (Hard Rule 2). Disclosed gap, not reassurance.

What was searched

PubMed listing "fexofenadine AND (ATP OR bioenergetics OR respiration)": 170 hits, top 10 read, all concerning P-glycoprotein (an ATP-binding cassette transporter), pharmacokinetics or reviews; none measured ATP or oxygen consumption. The in vitro mitochondrial paper [16] measured membrane potential and ROS, not ATP or oxygen consumption. A phrasing with quoted terms returned only the PubMed home page and was discarded.

Channel outcomes

PubMed only; OpenAlex and Crossref rate-limited. Repair pass 2026-10-08: PubMed phrasings with oxidative phosphorylation, respiratory chain, membrane potential and energy metabolism returned the PubMed home page (quoted-term failure) or a 404; fexofenadine with mitochondria and respiration or oxygen was rate-limited; WebSearch for fexofenadine with mitochondrial respiration, oxygen consumption or ATP content returned the Trybus news coverage and an unrelated Seahorse methods chapter (opened; it does not mention fexofenadine). A Tox21 mitochondrial membrane potential screening paper surfaced but sits behind a PMC browser check and was not opened. Maier 2018 (Nature, 1,200 drugs against gut bacteria) article page was opened; fexofenadine is not named in the text, and the supplement is not machine-readable here (robots.txt disallowed), so a possible fexofenadine row for the Gut microbiome entry could not be checked [36]. Tooling-limited in part. The adjacent depolarization finding is recorded in Mitochondrial burden and is not counted again here.

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.

  • Juice raises fexofenadine levels like other grapefruit interactions

    Where it comes from: General grapefruit-CYP3A4 lore. Origin not traced to a specific page in this review; included because the generalization is common and the direction is reversed for this drug.

    Why it fails: Fexofenadine is minimally metabolized (about 5%). Grapefruit, orange and apple juice lower exposure through OATP inhibition, by about 25% to 70% across crossover trials [3][6][7][8], and a review states grapefruit lowers fexofenadine and digoxin by inhibiting OATP-mediated absorption [25].

  • Any vitamin or mineral depletion attributed to fexofenadine

    Where it comes from: No specific claim located. The two consumer pages opened (Drugs.com food interactions, RxList) list only the juice and antacid cautions and make no depletion claim [22]. Repair pass: a Natural Medicines drug-induced nutrient depletion chart and a US Pharmacist article on drug-induced depletions were opened; neither lists fexofenadine or any H1 antihistamine (both cover H2 blockers and PPIs only) [33]. Other third-party depletion handbooks were not reachable.

    Why it fails: Nothing to rebut with a source; the entry records that the claim was searched and not found. No label, trial or mechanism supports depletion of any nutrient by fexofenadine. This row is partly tooling-limited and should be re-checked if a fexofenadine-specific depletion handbook entry is found.

How the body handles this medication

Metabolism and enzymes
About 5% of the total dose is eliminated by hepatic metabolism. Fexofenadine is a transporter substrate, and the label reports it had no effect on the pharmacokinetics of erythromycin or ketoconazole. No CYP induction or inhibition by fexofenadine is described in the label text retrieved. Aggregator records add CYP3A4 and intestinal microflora as minor routes.[3] FDA PI as reproduced on Drugs.com; [4] PubChem (DrugBank, T3DB)
Elimination
Roughly 80% recovered in feces and 11% in urine; mean elimination half-life 14.4 hours at steady state (60 mg twice daily). Oral clearance about 50.6 L/h and renal clearance about 4.32 L/h per the aggregator record.[3][4]
Absorption and transporters
Absolute bioavailability about 33%; Tmax 1 to 3 hours. Intestinal uptake depends on OATP1A2 (and OATP2B1), the transporters inhibited by fruit juice; P-glycoprotein limits absorption (ketoconazole and erythromycin raise levels).[4][7][12][3]
Renal impairment and age
Exposure rises and half-life lengthens in renal impairment; the PI recommends 60 mg once daily as the adult starting dose with decreased renal function. The OTC Drug Facts say to ask a doctor with kidney disease or at age 65 and over. Hepatic impairment did not substantially change kinetics.[1][3]
Juice, food, antacid interactions
PI: grapefruit, orange and apple juice may reduce absorption (estimated bioavailability reduction 36%); take with water. Taken within 15 minutes of Maalox, AUC fell 41% and Cmax 43% (current US label Section 7.1 [28]); UK SPC and Indian PI advise 2 hours between fexofenadine and aluminium or magnesium antacids [29][30]. A high-fat meal lowers exposure. OTC Drug Facts: do not take at the same time as aluminum or magnesium antacids; do not take with fruit juices.[1][3][4][28][29][30]
Sedation and adverse effects
Most common adverse reactions in patients 12 and older: headache, back pain, dizziness. Somnolence and fatigue are listed among pediatric reactions (ages 6 months to 5 years). Overdose: dizziness, drowsiness, dry mouth. The OTC Drug Facts retrieved carry no drowsiness warning.[1][3]

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.

  • Timing / every dose

    Take with water

    The label directs plain water and cautions against fruit juice (grapefruit, orange, apple) with the tablet. Reviews suggest the juice effect fades after several hours; a pharmacist can give an interval. This is a drug-absorption prompt, not a nutrient-status finding.

  • Timing / antacids

    Aluminum or magnesium antacids

    Do not take at the same time as aluminum or magnesium antacids per the Drug Facts. The PI trial window was within 15 minutes of an antacid dose (AUC down 41%, Cmax down 43%). The UK SPC and Indian PI advise 2 hours between the two [29][30]; confirm with a pharmacist.

  • Timing / beverages

    Green tea

    A single 10-person crossover found green tea extract sharply lowered fexofenadine exposure. A cautious practice is to keep tea and tablet apart until more data exist.

  • Renal function

    Kidney disease and age 65 and over

    Exposure rises with decreased renal function; the PI recommends a lower starting dose, and the OTC label says to ask a doctor.

  • Labs

    No routine nutrient labs indicated by this drug

    No source retrieved shows fexofenadine altering any measured nutrient. Test nutrients on the basis of the person's diet, other drugs and symptoms, not fexofenadine.

  • Special populations

    Pregnancy, children

    The OTC label advises asking a health professional in pregnancy or breast-feeding, and does not recommend the 180 mg tablet under age 12. Pediatric formulations have their own labels.

Overlap map, to prevent double counting

Entries resting on the same underlying source or mechanism (Hard Rule 9).

  • Oxidative stress

    Shares evidence with: Mitochondrial burden

    Note: Both lean on one paper, Trybus 2026 [16] (ROS-dependent mitochondrial dysfunction). It is one line of evidence counted in two entries. The rat malondialdehyde study [15] is independent but Tier B, small and single-lab.

  • Mitochondrial burden

    Shares evidence with: ATP production (ungraded)

    Note: Depolarization in [16] is the only adjacent finding. ATP was not measured, so ATP stays ungraded and gains nothing from this paper.

  • Fruit juice

    Shares evidence with: Green tea catechins

    Note: Same transporter mechanism (OATP1A2 inhibition) in separate human crossover trials [6][7][13]. Mechanistic overlap, not independent confirmation of one claim.

  • Fruit juice

    Shares evidence with: Aluminum and magnesium antacids

    Note: Both reduce absorption but by different proposed mechanisms (transport inhibition versus metal complexation). They share only the label text [1][3].

  • Copper

    Shares evidence with: Iron

    Note: No shared source. Both ungraded after the same trace-mineral searches and graded separately per Hard Rule 7.

  • Iron

    Shares evidence with: Oxygen delivery/utilization

    Note: The restless legs case with unremarkable iron indices [19] is a single patient and supports neither entry. No shared graded evidence.

  • Gut microbiome risk

    Shares evidence with: None graded

    Note: The in vitro culture study [18] stands alone; no human microbiome source overlaps.

All references used above
  1. ALLEGRA ALLERGY (fexofenadine HCl 180 mg) tablet, coated, Chattem, DailyMed OTC Drug Facts. — Regulatory label (Tier A). Opened 2026-10-07 via summarizing fetch. Source of aluminum or magnesium antacid, fruit juice and kidney disease statements; OTC panel has no pharmacology section.
  2. Generic fexofenadine OTC labels (Proficient Rx f9a7e836-6055-484f-a197-181220428574; AuroHealth suspension e8e35d7a-a86b-4d37-979b-f454978f070b; Bryant Ranch 6bc92969-0d06-4bf5-a634-80964464546c; Sciegen b7e9477d-33d9-4463-b8a6-69af5f71ce35), DailyMed. — Regulatory labels (Tier A), all HUMAN OTC DRUG LABEL, no pharmacokinetic sections. Confirm the same juice and antacid cautions. A fifth generic label (Dr. Reddy's) was rate-limited and not opened.
  3. Allegra (fexofenadine HCl) prescribing information, sanofi-aventis, as reproduced on Drugs.com Pro, "Revised: 3/2012". — Regulatory label text (Tier A) reproduced by a third party; read via summarizing fetch with 125-character quote limits. The page itself states some sections are missing. Source for PK, renal dosing, 41% antacid AUC reduction, 36% juice bioavailability reduction. Current DailyMed Rx label not found (all DailyMed labels retrieved were OTC).
  4. PubChem compound record for fexofenadine (CID 3348), Pharmacology and Biochemistry section (aggregates DrugBank, HSDB/AHFS, T3DB). — Secondary aggregator, used only for corroboration of oral clearance, renal clearance and high-fat meal effect. Fetched via PUG-View.
  5. Wikipedia, "Fexofenadine". — Tier D reference; used only for the ATC code R06AX26 (it cites WHO) and as a pointer to the antacid complexation explanation. The WHO ATC/DDD index and the cited chemistry paper were not opened.Tier D: no claim above depends on it.
  6. Dresser GK, et al. Fruit juices inhibit organic anion transporting polypeptide-mediated drug uptake to decrease the oral availability of fexofenadine. Clin Pharmacol Ther 2002;71:11-20. — Randomized crossover, n=10. PMID 11823753; DOI 10.1067/mcp.2002.121152. Abstract only, via OpenAlex summary and PubMed listing summary; no CI retrieved.
  7. Dresser GK, et al. Effect of grapefruit juice volume on the reduction of fexofenadine bioavailability. Clin Pharmacol Ther 2005;77:170-177. — Randomized 4-way crossover, n=12. PMID 15735611; DOI 10.1016/j.clpt.2004.10.005. Abstract via OpenAlex (reconstructed from inverted index).
  8. Won CS, et al. A modified grapefruit juice eliminates two compound classes as major mediators of the grapefruit juice-fexofenadine interaction. J Clin Pharmacol 2013;53:982-990. — Randomized 3-way crossover, n=18. PMID 23878024; DOI 10.1002/jcph.136. Abstract via OpenAlex (reconstructed).
  9. Akamine Y, et al. The change of pharmacokinetics of fexofenadine enantiomers through the single and simultaneous grapefruit juice ingestion. Drug Metab Pharmacokinet 2015. — n=14. PMID 26213156. Abstract numbers via PubMed listing summary only.
  10. Kharasch ED, et al. Evaluation of first-pass CYP3A and P-glycoprotein activities using alfentanil and fexofenadine in combination. J Clin Pharmacol 2005. — Two crossover trials in healthy volunteers; sample size not stated. PMID 15601808. Abstract numbers via PubMed listing summary only.
  11. Bailey DG. Fruit juice inhibition of uptake transport: a new type of food-drug interaction. Br J Clin Pharmacol 2010. — Review (narrative). PMID 21039758. Used only for the juice time course (more than 2 h, less than 4 h) and naringin. Abstract via PubMed listing summary.
  12. Glaeser H, et al. Intestinal drug transporter expression and the impact of grapefruit juice in humans. Clin Pharmacol Ther 2007. — Human study. PMID 17215845. OATP1A2 as key uptake transporter; juice with or 2 h before reduced exposure. Abstract via PubMed listing summary.
  13. Misaka S, et al. Exposure of fexofenadine, but not pseudoephedrine, is markedly decreased by green tea extract in healthy volunteers. Clin Pharmacol Ther 2022;112:627-634. — Randomized crossover, n=10. PMID 35678032; DOI 10.1002/cpt.2682. Abstract via OpenAlex.
  14. Kullak-Ublick GA, et al. No major effects of vitamin D3 on absorption and pharmacokinetics of folic acid and fexofenadine in healthy volunteers. Eur J Clin Pharmacol 2016. — n=10. PMID 27023466. Null finding. Abstract via PubMed listing summary.
  15. Mahmood E, et al. Histological and biochemical study of the effect of fexofenadine on salivary gland in rats. Georgian Med News 2024;(347):38-40. — Rat study (Tier B), n=30. PMID 38609111. Abstract via OpenAlex (reconstructed); PubMed listing summary differed on which groups were raised.
  16. Trybus E, et al. Fexofenadine induces ROS-dependent mitochondrial dysfunction and suppresses PI3K/AKT and MAPK signaling in cervical and lung cancer cells. Cancers (Basel) 2026;18(13):2156. — In vitro (Tier B). PMID 42449698. Article page read via summarizing fetch. Concentrations 150 to 400 micromolar.
  17. Wang WT, et al. Terfenadine induces anti-proliferative and apoptotic activities in human hormone-refractory prostate cancer. Naunyn Schmiedebergs Arch Pharmacol 2014. — In vitro. PMID 24048439. Fexofenadine "little effect". Abstract via PubMed listing summary.
  18. Hammouda ZK, et al. Fexofenadine HCl enhances growth, biofilm, and lactic acid production of Limosilactobacillus reuteri and Bifidobacterium longum. BMC Microbiol 2025;25:430. — In vitro (Tier B). PMID 40640705; DOI 10.1186/s12866-025-04130-0. Abstract via OpenAlex.
  19. Albeshry AM, et al. Restless legs syndrome associated with fexofenadine use: a case report. Clin Case Rep 2026. — Single case report. PMID 41626088. Iron indices unremarkable. Abstract via PubMed listing summary.
  20. Zou L, et al. Bacterial metabolism rescues the inhibition of intestinal drug absorption by food and drug additives. Proc Natl Acad Sci U S A 2020. — Mouse and in vitro. PMID 32571913. Not used for any grade (food dye excipients, not nutrients); listed because it surfaced in the microbiome query. Abstract via PubMed listing summary.
  21. Khafagy ES, et al. Expired fexofenadine hydrochloride as a corrosion inhibitor for copper in MSF desalination applications. Sci Rep 2026. — Materials study, no biological relevance. PMID 42156540. Listed as a non-qualifying copper hit. Abstract via PubMed listing summary.Not evidence for a copper entry.
  22. Consumer pages: Drugs.com food interactions for fexofenadine; RxList Allegra drug page. — Tier D, opened for the circulating-claim audit only. Neither makes a nutrient depletion claim.
  23. Wulf HC, et al. Cimetidine, fexofenadine and zinc sulphate in the treatment of erythropoietic protoporphyria. Photodiagnosis Photodyn Ther 2025; Akamatsu H, et al. Effect of fexofenadine on pruritus in a mouse model (HR-ADf) of atopic dermatitis. J Int Med Res 2006. — PMIDs 40412707 and 17133778. Non-qualifying copper and zinc hits (no nutrient status measured). Abstracts via PubMed listing summary.
  24. Andrade C. Fruit juice, organic anion transporting polypeptides, and drug interactions in psychiatry. J Clin Psychiatry 2014. — Narrative review. PMID 25470100. Used only for the advice to separate medicines from juice by at least 4 hours. Abstract via PubMed listing summary.
  25. Bressler R. Grapefruit juice and drug interactions: exploring mechanisms of this interaction and potential toxicity for certain drugs. Geriatrics 2006. — Narrative review. PMID 17112309. States grapefruit juice lowers fexofenadine and digoxin by inhibiting OATP-mediated absorption. Abstract via PubMed listing summary.
  26. Vanhove T, et al. Fexofenadine, a putative in vivo P-glycoprotein probe, fails to predict clearance of the substrate tacrolimus in renal recipients. Clin Pharmacol Ther 2017. — 70 renal transplant recipients. PMID 28437851. Hematocrit was a covariate of tacrolimus clearance; no fexofenadine effect on hematocrit reported. Abstract via PubMed listing summary.
  27. De Melo Mendes V, et al. Antileishmanial activity of H1-antihistamine drugs and cellular alterations in Leishmania (L.) infantum. Acta Trop 2019;195:6-14. — In vitro parasite study. PMID 31002807. Fexofenadine lacked activity; other antihistamines depolarized parasite mitochondria. Abstract via PubMed listing summary.
  28. Fexofenadine hydrochloride current US prescribing information (Sections 6.1 and 7), medlibrary.org label pages. — Regulatory label text (Tier A) reproduced by a label library; opened 2026-10-08 via summarizing fetch with quote limits. Source of antacid AUC 41% and Cmax 43% in "healthy adult subjects", fruit juice bioavailability reduction 36%, approximately 5% metabolism, and ketoconazole and erythromycin effects. Sections 12 and the revision date were not on the pages opened.
  29. Xadine (fexofenadine) tablet Summary of Product Characteristics, Searle Company. — Regulatory label (Tier A, UK SPC). Opened 2026-10-08. States antacid reduction "most likely due to binding in the gastrointestinal tract", advises 2 hours between doses, says fexofenadine does not undergo hepatic biotransformation and contains no food or nutrient interaction beyond taking with water. No study cited for the antacid statement.
  30. Allegra (fexofenadine) prescribing information, Sanofi India. — Regulatory label (Tier A, India). Opened 2026-10-08. Repeats the 15-minute antacid finding and the 2-hour gap, with no sample size; no laboratory or hematologic findings.
  31. Sanofi clinical study summary M016455A: fexofenadine HCl 180 mg once daily versus placebo in chronic idiopathic urticaria. — Phase IIIa multicenter randomized double-blind placebo-controlled trial (Tier A, sponsor trial summary), 259 randomized (167 fexofenadine, 92 placebo), 28 days. Opened 2026-10-08. Laboratory tests including hematologic analysis showed no clinically relevant change from baseline in either group; no hemoglobin or iron values are reported in the summary.
  32. Fexofenadine hydrochloride US label, Adverse Reactions pages (Section 6.1 laboratory abnormalities), medlibrary.org. — Regulatory label text (Tier A). Opened 2026-10-08. States frequency and magnitude of laboratory abnormalities were similar between fexofenadine and placebo; no hematologic reaction named on the pages read.
  33. Natural Medicines (Therapeutic Research) chart, Drug-Induced Nutrient Depletions; and US Pharmacist, "Drug-induced nutrient depletions: what pharmacists need to know" (2019). — Tier D consumer and professional depletion references, opened 2026-10-08 for the circulating-claim audit only. Neither lists fexofenadine or an H1 antihistamine; both cover H2 blockers or PPIs only.Tier D: used for a negative finding only.
  34. Craig-McFeely PM, Acharya NV, Shakir SA. Evaluation of the safety of fexofenadine from experience gained in general practice use in England in 1997. Eur J Clin Pharmacol 2001;57:313-320. — Prescription-event monitoring observational cohort of fexofenadine users (35,817 questionnaires sent, 18,238 returned). Abstract only via publisher page; paywalled full text not opened. Abstract reports adverse-event counts, not hematologic or iron measures.Full text not opened (paywall); no nutrient or hematologic claim rests on it.
  35. Clinical Pharmacokinetics of Fexofenadine: A Systematic Review. Pharmaceutics 2024;16(12):1619. — Systematic review (Tier A for pharmacokinetics). DOI 10.3390/pharmaceutics16121619. Opened 2026-10-08 via summarizing fetch; reports juice crossover figures but does not mention antacids, iron, copper or hemoglobin, so it supplied no antacid primary study.
  36. Maier L, et al. Extensive impact of non-antibiotic drugs on human gut bacteria. Nature 2018;555:623-628. — In vitro screen of about 1,200 drugs against gut bacterial strains. Article page opened 2026-10-08: fexofenadine is not named in the text. The Supplementary Table was not opened (the host disallows automated retrieval), so whether fexofenadine appears in it is unknown. Not used for any grade.Supplement not opened; no claim rests on it.
  37. PubMed listing, fexofenadine AND (magnesium OR calcium OR antacid), 33 records, first 10 read (relevance order). — Listing opened 2026-10-08. Records were juice and transporter reviews, mouse OATP2B1 studies, a pregnancy transporter-activity study in HIV (PMID 36087110) and unrelated items; none was an antacid pharmacokinetic study and none measured magnesium or calcium status in fexofenadine users. Records 11 to 33 were not read.