Brompheniramine maleate

What it is

Brompheniramine maleate is a first-generation sedating antihistamine of the alkylamine class, sold as the maleate salt. It is the bromine-substituted analogue of chlorpheniramine. In the United States today it is found almost entirely in children's cold, cough and allergy liquids, commonly at 2 mg per 10 ml, and in a small number of prescription syrups combined with pseudoephedrine and dextromethorphan. It blocks histamine H1 receptors, dries secretions through anticholinergic action, and sedates.

What the research says

The literature on brompheniramine is noticeably thinner than for its siblings, and that thinness is the most honest thing to report about it. We found no systematic review of brompheniramine and no Cochrane review specific to it. The modern placebo-controlled base is three multicentre trials published between 1996 and 1998 that share authors: all three found extended-release brompheniramine 12 mg twice daily better than placebo and better than terfenadine or loratadine for allergic rhinitis, but none of them publishes an effect size or a confidence interval in its abstract, only P values, and in the dose-ranging trial the 8 mg dose was in general no better than terfenadine while the placebo arm had only half as many participants as each active arm. The harm side is clearer than the benefit: in that same trial 57.5% of people on 12 mg reported an adverse experience against 39.6% on placebo, somnolence was the effect that distinguished it from second-generation comparators, Cochrane found no benefit from antihistamines for colds in young children or for glue ear, and the prescription label warns that in overdose antihistamines may cause hallucinations, convulsions and death in infants and small children.

Evidence grade: Limited evidence.

How it works

Drug class: First-generation (sedating) H1-antihistamine, alkylamine class, with anticholinergic activity; maleate salt. Listed as an over-the-counter antihistamine active ingredient in the United States.

Brompheniramine competes with histamine for receptor sites on the cells histamine acts on, which blunts the allergic response in the lining of the nose: the widening of blood vessels, the leakiness that causes swelling, and the increase in mucus. It also has anticholinergic drying effects and sedates. Taken by mouth it is well absorbed, with a peak blood level about five hours after a 4 mg dose; it leaves the body mainly in the urine as breakdown products, and the liver is assumed to be where that breakdown happens. (Source 1)

What it is used for

• Three placebo-controlled multicentre trials from 1996 to 1998, sharing authors, found extended-release brompheniramine 12 mg twice daily better than placebo and better than terfenadine or loratadine. None of them publishes an effect size or confidence interval in the abstract, only P values, and the 8 mg dose was in general no better than terfenadine. This is the whole of the modern placebo-controlled base we could find for this drug. Evidence: limited. (Source 2)
• Brompheniramine's current US market is almost entirely paediatric cold, cough and allergy liquids. Cochrane found antihistamine monotherapy had no clinically significant effect on individual cold symptoms and found no evidence of effectiveness for antihistamine-containing combinations in young children. Evidence: not-supported. (Source 3)
• Cochrane pooled 16 trials in 1880 children and found no benefit on any outcome with 11% more side effects, number needed to harm 9, and recommended against use. Evidence: not-supported. (Source 4)
• Both the single-ingredient Drug Facts label and the prescription syrup label rule this out. The syrup's warnings section states that antihistamines may produce excitation rather than sedation in young children, and that in overdose they may cause hallucinations, convulsions and death in infants and small children. Evidence: not-supported. (Source 5)

Interactions

• Monoamine oxidase inhibitors (label): MAO inhibitors lengthen and intensify the drying anticholinergic effects of antihistamines, and the label for a brompheniramine-containing syrup says concomitant administration should be avoided. (Source 6)
• Alcohol and other central nervous system depressants (label): Antihistamines add to the effect of alcohol, hypnotics, sedatives, tranquillisers and anti-anxiety drugs. The Drug Facts label for the single-ingredient liquid tells people to avoid alcoholic drinks. (Source 6)
• Sedatives and tranquillisers (label): The over-the-counter label names sedatives and tranquillisers as increasing drowsiness and tells people taking them to ask a doctor or pharmacist first. (Source 5)
• Other anticholinergic medicines (label): Brompheniramine has its own anticholinergic drying effect, so it adds to the load from other drugs that block acetylcholine. The label states the drying effect directly; the additive arithmetic is documented for the class rather than for this drug by name. (Source 1)
• Grapefruit, St John's wort, melatonin, valerian and kava (theoretical): We found no interaction study of brompheniramine with any supplement or food. The label states only that the liver is assumed to be the main site of its metabolism, and does not name the enzymes involved, so even a mechanistic prediction cannot be made with confidence. Limit: This is an absence of evidence, recorded as such. We searched PubMed for brompheniramine with grapefruit, St John's wort, melatonin, valerian, kava and CYP interactions and found no clinical or pharmacokinetic interaction study. (Source 1)

Stopping it

• We found no deprescribing trial, no tapering study and no withdrawal syndrome described for brompheniramine. The only stopping-relevant observation we could source is from inside one of the allergic rhinitis trials, where the somnolence that brompheniramine caused became less frequent the longer treatment continued, which points to tolerance to the sedation rather than to anything happening on withdrawal. (Source 7)
• For the class, the clearest stopping-adjacent evidence comes from a driving study of a related alkylamine antihistamine, where day-one impairment had gone by day eight of continuous dosing. Nothing in what we reached describes rebound or withdrawal when brompheniramine is stopped. (Source 8)

What goes wrong

The higher brompheniramine dose produced substantially more adverse experiences than placebo or either comparator. (Source 9)

• Randomized trial, Certainty not rated.
• Size: 370 participants enrolled; 155 (41.9%) reported adverse experiences.
• Who: Adults with allergic rhinitis.
• How long: 14 days.
• Result: Adverse experience rate 57.5% on brompheniramine 12 mg versus 38.1% on brompheniramine 8 mg, 31.1% on terfenadine and 39.6% on placebo (p < 0.05 for the 12 mg comparison)
• Funding: not stated in the abstract.

Limit of this finding: One figure in this sentence does not sit with its own argument: the paper reports a higher adverse-experience rate on placebo (39.6%) than on brompheniramine 8 mg (38.1%), so the 8 mg arm was not worse than placebo even though the sentence lists placebo and 8 mg together as the comparators the 12 mg arm exceeded. The significance statement applies to the 12 mg dose. Nothing here should be read as showing that every brompheniramine dose was worse tolerated than placebo.

The overall rate of adverse experiences in the brompheniramine 12 mg treatment group (57.5%) was significantly greater (p < 0.05) than for brompheniramine 8 mg (38.1%), terfenadine (31.1%), and placebo (39.6%).

Somnolence was the adverse effect that distinguished brompheniramine from second-generation comparators in all three trials, and it diminished with continued dosing in one of them. (Source 7)

• Randomized trial, Certainty not rated.
• Size: 338 participants in this trial.
• Who: Adults with allergic rhinitis.
• How long: 7 days.
• Result: Central nervous system symptoms were the commonest adverse experiences; somnolence reported most often by brompheniramine patients, becoming less frequent as treatment continued.
• Funding: not stated in the abstract.

somnolence was reported most frequently by patients taking brompheniramine, and its occurrence was less frequent as treatment continued

In the first trial too, somnolence clustered in the brompheniramine group. (Source 2)

• Randomized trial, Certainty not rated.
• Size: 287 participants.
• Who: Adults with allergic rhinitis.
• How long: 14 days.
• Result: No rates are given in the abstract; central nervous system complaints were the commonest adverse experiences in all three arms.
• Funding: not stated in the abstract.

Limit of this finding: The abstract gives no numbers for somnolence in this trial, so the claim is directional only.

Central nervous system-related complaints were the most frequently reported adverse experiences among all three groups; somnolence was reported most frequently by brompheniramine-treated subjects.

Cochrane found no benefit and measurable harm from antihistamines for otitis media with effusion in children. (Source 4)

• Systematic review, Certainty not rated.
• Size: 16 studies, 1880 participants.
• Who: Children with otitis media with effusion.
• How long: Searches to February 2011.
• Result: No statistical or clinical benefit for any outcome; 11% more side effects in treated children, number needed to harm 9.
• Funding: not stated in the abstract.

Limit of this finding: Class-level evidence; brompheniramine is not identified separately. The '11% more side effects' is the review's own wording for an absolute difference of about 11 percentage points between treated and untreated children, which is what its number needed to harm of 9 corresponds to. It does not mean side effects were 11% more likely in relative terms.

No statistical or clinical benefit was found for any of the interventions or outcomes studied. However, treated study subjects experienced 11% more side effects than untreated subjects (number needed to treat to harm = 9).

The prescribing information for a brompheniramine syrup warns that in overdose antihistamines can cause hallucinations, convulsions and death in infants and small children. (Source 10)

• Official position, Certainty not rated.
• Size: Not applicable - a regulatory label.
• Who: Infants and small children given antihistamines in overdose.
• How long: Not applicable.
• Result: No rates are given.
• Funding: Not applicable.

Especially in infants and small children, antihistamines in overdosage may cause hallucinations, convulsions, and death.

The same label records that antihistamines can produce excitation rather than sedation in young children. (Source 10)

• Official position, Certainty not rated.
• Size: Not applicable - a label.
• Who: Young children.
• How long: Not applicable.
• Result: No rates are given.
• Funding: Not applicable.

Antihistamines may diminish mental alertness. In the young child, they may produce excitation.

The label's adverse reaction list for a brompheniramine-containing syrup includes blood disorders alongside the common drying and sedating effects. (Source 11)

• Official position, Certainty not rated.
• Size: Not applicable - a label.
• Who: Patients taking the syrup.
• How long: Not applicable.
• Result: No incidence figures accompany the list; the most frequent reactions are named separately as sedation, dryness of mouth, nose and throat, thickening of bronchial secretions and dizziness.
• Funding: Not applicable.

Limit of this finding: This is a combination product's label covering brompheniramine, pseudoephedrine and dextromethorphan together, so individual reactions in the list cannot be assigned to brompheniramine alone. The list carries no incidence bands at all.

Hematologic System: Hemolytic anemia, thrombocytopenia, agranulocytosis.

A child survived a brompheniramine dose of 300 to 900 mg, which the label itself uses to warn that individual responses to small amounts are unpredictable. (Source 12)

• Case report, Very low certainty.
• Size: One child aged two and a half.
• Who: A single paediatric overdose case cited in the label.
• How long: Single acute ingestion.
• Result: Survival after an estimated 300 to 900 mg; the label's framing is that individuals may respond in an unexpected manner to apparently small amounts.
• Funding: Not applicable.

Limit of this finding: A single case cited second-hand in a label, with a dose range spanning a factor of three. It supports nothing about a safe or dangerous threshold.

Another 2½-year-old child survived a dose of 300-900 mg of brompheniramine.

Ten unexpected infant deaths in one US state had cold-medicine ingredients, antihistamine among them, on post-mortem toxicology. (Source 13)

• Case series, Very low certainty.
• Size: Ten infant deaths among all unexpected infant deaths autopsied in Arizona in 2006.
• Who: Infants aged 17 days to 10 months who died unexpectedly.
• How long: Deaths occurring in 2006.
• Result: Post-mortem toxicology found recent administration of pseudoephedrine, antihistamine, dextromethorphan and/or other cold-medication ingredients; only one of the ten had the medicine prescribed by a clinician.
• Funding: not stated in the abstract.

Limit of this finding: A case series from a child fatality review. It cannot establish that the medicines caused the deaths, the antihistamine is not identified as brompheniramine, and the authors themselves write only that the findings raise concern.

Postmortem toxicology testing found evidence of recent administration of pseudoephedrine, antihistamine, dextromethorphan, and/or other cold-medication ingredients in these infants.

The reviewers of those deaths concluded that cold medicines should not be given to infants. (Source 14)

• Case series, Very low certainty.
• Size: Ten infant deaths.
• Who: Infants under one year.
• How long: 2006.
• Result: No rate; a recommendation drawn from the series.
• Funding: not stated in the abstract.

These findings support the recommendation that such medications not be given to infants.

Cough and cold medicines account for an estimated 26,735 US emergency department visits a year, most of them for non-therapeutic use. (Source 15)

• Survey study, Certainty not rated.
• Size: 1396 surveillance cases representing an estimated 26,735 annual visits.
• Who: People of all ages presenting to US emergency departments.
• How long: 2017 to 2019.
• Result: 26,735 visits annually (95% CI 21,679-31,791), 1.3% of all medication adverse event visits; 61.4% attributed to non-therapeutic use; 74.0% of visits by children under 4 were unsupervised exposures.
• Funding: not stated in the abstract.

Limit of this finding: This covers all over-the-counter cough and cold medicines, not brompheniramine specifically. The figures are weighted national estimates projected from 1396 surveillance cases in a sample of emergency departments, and the 1.3% denominator is emergency visits for medication adverse events, not all emergency visits and not all users of these medicines.

accounting for 1.3% (95% CI, 1.2-1.5%) of all ED visits for medication adverse events

First-generation antihistamines as a class were associated with about double the odds of injurious falls or fracture in older people. (Source 16)

• Meta-analysis, Low certainty.
• Size: Five observational studies.
• Who: Elderly patients.
• How long: Databases searched to November 2016.
• Result: OR 2.03, 95% CI 1.49-2.76, I2 = 0%.
• Funding: not stated in the abstract.

Limit of this finding: Class-level observational evidence; brompheniramine is not separately identified.

First-generation antihistamine use is considerably associated with an increased risk of injurious falls or fracture among the elderly.

The Drug Facts label for a single-ingredient brompheniramine liquid instructs that it must not be used to sedate a child. (Source 5)

• Official position, Certainty not rated.
• Size: Not applicable - a label.
• Who: Children aged 6 and over.
• How long: Not applicable.
• Result: No rates given.
• Funding: Not applicable.

▪to sedate a child or to make a child sleepy

Cumulative use of strong anticholinergics, of which first-generation antihistamines are one of the commonest classes, tracked with incident dementia in a long-running cohort. (Source 17)

• Cohort study, Certainty not rated.
• Size: 3434 participants aged 65+; 797 developed dementia.
• Who: Older adults in an integrated health system in Seattle.
• How long: Mean follow-up 7.3 years.
• Result: Adjusted HR 1.54 (95% CI 1.21-1.96) for more than 1095 total standardized daily doses versus non-use.
• Funding: Research Support, N.I.H., Extramural per the PubMed record.

Limit of this finding: Observational, class-level, and brompheniramine is not named. It does not establish causation.

Higher cumulative anticholinergic use is associated with an increased risk for dementia.

What the evidence supports

In a placebo-controlled multicentre trial, extended-release brompheniramine 12 mg twice daily beat both placebo and terfenadine on summed allergic rhinitis symptom scores. (Source 2)

• Randomized trial, Certainty not rated.
• Size: 287 participants (brompheniramine 96, terfenadine 96, placebo 95)
• Who: Adults with symptoms of allergic rhinitis, multicentre, United States.
• How long: 14 days, with assessments on days 3, 7 and 14.
• Result: Brompheniramine significantly better than terfenadine and placebo (P <= .05) at every post-baseline assessment on both summed symptom scores and both global assessments; terfenadine beat placebo only on the physician global at day 14.
• Funding: not stated in the abstract; the PubMed record lists Research Support, Non-U.S. Gov't and one author (Furey SA) appears across all three brompheniramine trials we found.

Limit of this finding: No effect size, confidence interval or absolute difference is reported in the abstract, only P values, so the size of the benefit cannot be judged from what is published there. The comparator terfenadine has since been withdrawn in many markets for cardiac toxicity.

At all post-baseline evaluations (days 3, 7, and 14), brompheniramine was significantly better (P < or = .05) than terfenadine and placebo for both sets of summed symptom scores and for both global assessments.

The trial's own conclusion is a comparative claim against a second-generation antihistamine. (Source 18)

• Randomized trial, Certainty not rated.
• Size: 287 participants.
• Who: Adults with allergic rhinitis.
• How long: 14 days.
• Result: Brompheniramine 12 mg twice daily provided significantly better relief than terfenadine 60 mg twice daily.
• Funding: not stated in the abstract.

A nonprescription, extended-release formulation of brompheniramine, 12 mg bid, provided significantly better relief of symptomatic allergic rhinitis than terfenadine, 60 mg bid.

A second placebo-controlled multicentre trial found brompheniramine 12 mg twice daily better than loratadine and placebo. (Source 7)

• Randomized trial, Certainty not rated.
• Size: 338 participants (brompheniramine 112, loratadine 112, placebo 114)
• Who: Adults with symptoms of allergic rhinitis, multicentre, United States.
• How long: 7 days, with assessments on days 3 and 7.
• Result: Brompheniramine significantly better than loratadine and placebo on both summed symptom score sets and all three global assessments at every post-baseline evaluation; loratadine beat placebo on some but not all measures.
• Funding: not stated in the abstract; the PubMed record lists Research Support, Non-U.S. Gov't.

Limit of this finding: Again only P values, with no effect size or confidence interval in the published abstract. The three brompheniramine allergic rhinitis trials we found share authors and sponsorship characteristics and all favour the non-prescription product over prescription competitors, which is a pattern a reader should weigh.

At all post-baseline evaluations (days 3, 7, and averaged over the two days), brompheniramine was significantly better than loratadine and placebo for both sets of summed symptom scores and all three global assessments.

What the evidence does not support

The lower brompheniramine dose did not clearly separate from the comparator. (Source 9)

• Randomized trial, Certainty not rated.
• Size: 370 participants.
• Who: Adults with allergic rhinitis.
• How long: 14 days.
• Result: Brompheniramine 8 mg twice daily was in general comparable to terfenadine 60 mg twice daily.
• Funding: not stated in the abstract.

In general, brompheniramine 8 mg was comparable to terfenadine.

Cochrane found no clinically significant effect of antihistamine monotherapy on individual common cold symptoms. (Source 3)

• Systematic review, Certainty not rated.
• Size: 18 RCTs, 4342 participants.
• Who: Adults and children with the common cold.
• How long: Up to ten days.
• Result: No clinically significant effect on nasal obstruction, rhinorrhoea or sneezing; no difference from placebo after day two.
• Funding: not stated in the abstract.

Limit of this finding: Class-level evidence for antihistamine monotherapy. Brompheniramine is not separately identified in the abstract.

There is no clinically significant effect on nasal obstruction, rhinorrhoea or sneezing.

Cochrane found no evidence of effectiveness for antihistamine-containing cold combinations in young children. (Source 19)

• Systematic review, Low certainty.
• Size: 30 studies, 6304 participants; children in nine trials, very young children in three.
• Who: Children and adults with the common cold.
• How long: Varied.
• Result: One trial in children aged 2 to 12 and two in adults found no beneficial effect; the review states there is no evidence of effectiveness in young children.
• Funding: not stated in the abstract.

There is no evidence of effectiveness in young children.

Where the evidence is mixed

In the dose-ranging trial, brompheniramine 8 mg twice daily was no better than terfenadine, and terfenadine itself did not beat placebo on symptom severity. (Source 9)

• Randomized trial, Certainty not rated.
• Size: 370 participants enrolled (brompheniramine 12 mg 106, 8 mg 105, terfenadine 106, placebo 53)
• Who: Adults with seasonal and/or perennial allergic rhinitis, multicentre.
• How long: 14 days, with assessments on days 3, 7 and 14.
• Result: On days 3 and 7 brompheniramine 12 mg improved total symptom and total nasal symptom severity significantly more than placebo (p < 0.05) while terfenadine did not differ from placebo; brompheniramine 8 mg was in general comparable to terfenadine.
• Funding: not stated in the abstract.

Limit of this finding: The placebo group had only 53 participants against 106 in each active arm, which weakens every comparison against placebo.

On days 3 and 7, the total symptom and total nasal symptom severity scores for subjects receiving brompheniramine 12 mg were significantly more improved than for placebo (p < 0.05); terfenadine was not different from placebo

Where the research disagrees

Whether brompheniramine really outperforms second-generation antihistamines for allergic rhinitis, or whether the trials showing that are an artefact of sponsorship and trial design

• Thoden and colleagues, randomised placebo-controlled multicentre dose-ranging trial, 1998, randomised, double-blind, placebo-controlled multicentre parallel trial with an unbalanced placebo arm (53 versus 106 per active arm): On days 3 and 7, the total symptom and total nasal symptom severity scores for subjects receiving brompheniramine 12 mg were significantly more improved than for placebo (p < 0.05); terfenadine was not different from placebo (Source 9)
• The same trial's safety result, which is the price of that benefit, the same randomised trial, adverse experience interviews: The overall rate of adverse experiences in the brompheniramine 12 mg treatment group (57.5%) was significantly greater (p < 0.05) than for brompheniramine 8 mg (38.1%), terfenadine (31.1%), and placebo (39.6%). (Source 9)
• Simons and Simons, narrative review of a century of H1-antihistamines, 2011, narrative review with no stated search method: Unlike first (old)-generation H(1)-antihistamines introduced from 1942 to the mid-1980s, most of the second (new)-generation H(1)-antihistamines introduced subsequently have been investigated extensively with regard to clinical pharmacology, efficacy, and safety; moreover, they are relatively free from adverse effects and not causally linked with fatalities after overdose. (Source 20)

How much

• Reference intake: There is no reference intake, because this is a medicine and not a nutrient. How much a person takes is set by the product label or by a prescriber. As a position, the US over-the-counter antihistamine monograph, in the Code of Federal Regulations edition revised as of 1 April 2025, directs 4 mg every 4 to 6 hours for adults and children 12 and over, 2 mg every 4 to 6 hours for children 6 to under 12, and a doctor to be consulted for children under 6. (Source 21)
• Upper limit: There is no toxicological upper limit of the kind set for nutrients. The regulatory ceiling, as a position of the US Food and Drug Administration recorded in the Code of Federal Regulations edition revised as of 1 April 2025, is 24 mg in 24 hours for adults and children 12 and over, and 12 mg in 24 hours for children 6 to under 12. (Source 21)
• Studied: The first placebo-controlled trial gave extended-release brompheniramine 12 mg twice daily for 14 days to 96 adults with allergic rhinitis, against terfenadine 60 mg twice daily (96) and placebo (95). (Source 2)
• Studied: The second gave brompheniramine 12 mg twice daily for 7 days to 112 adults, against loratadine 10 mg once daily (112) and placebo (114), blinded with a double-dummy technique. (Source 7)
• Studied: The dose-ranging trial gave brompheniramine 12 mg (106 subjects) or 8 mg (105) twice daily for 14 days, against terfenadine 60 mg twice daily (106) and placebo (53). (Source 9)
• Studied: The prescription syrup's pharmacokinetic description is based on a single 4 mg oral dose, after which peak plasma concentration is reached in 5 hours. (Source 1)

A common belief, and what the research shows

The belief: Brompheniramine is a gentle children's medicine, which is why it is sold in sweet-flavoured liquids for children.

What the research shows: The labels on those products say the opposite of gentle. The single-ingredient Drug Facts label carries the instruction '▪to sedate a child or to make a child sleepy' under the heading Do not use, and the prescription syrup's warnings section states 'Especially in infants and small children, antihistamines in overdosage may cause hallucinations, convulsions, and death.' and 'Antihistamines may diminish mental alertness. In the young child, they may produce excitation.' The benefit side in children is not there either: Cochrane's conclusion on antihistamine-containing cold combinations is 'There is no evidence of effectiveness in young children.' and on antihistamines for glue ear 'The pooled data demonstrate no benefit and some harm from the use of antihistamines or decongestants alone or in combination in the management of OME'.

Questions and answers

What is it?

Brompheniramine maleate is a first-generation sedating antihistamine of the alkylamine class, the bromine-substituted sibling of chlorpheniramine, sold as the maleate salt. In the United States today it appears almost entirely in children's cold, cough and allergy liquids, usually at 2 mg per 10 ml, and in some prescription syrups. It blocks histamine H1 receptors and has anticholinergic drying and sedative effects as well. (Source 1)

What does it do in the body?

It competes with histamine at the H1 receptor, which reduces the vasodilation, leaky capillaries and mucus production histamine causes in the lining of the nose. It also blocks acetylcholine receptors, which dries secretions, and it sedates. It is well absorbed by mouth, with peak blood levels about five hours after a 4 mg dose, and is cleared mainly in the urine after liver metabolism. (Source 1)

Is it good or bad for you?

The honest answer is that the evidence is too thin to be confident either way, and the harm is better measured than the benefit. Three trials from the 1990s found the 12 mg twice-daily dose better than placebo for hay fever, but at that dose adverse experiences were reported by 57.5% of participants against 39.6% on placebo. For colds and glue ear in children the reviews find no benefit, and the label warns against using it to sedate a child. (Source 9)

How do you get more of it?

It is a medicine, not a nutrient, so there is no reason to seek more of it. The US OTC monograph sets the permitted amount at 4 mg every four to six hours with a ceiling of 24 mg a day for adults and children 12 and over, 2 mg every four to six hours up to 12 mg a day for children 6 to under 12, and says to consult a doctor for children under 6. That is the regulator's position, not advice. (Source 21)

If it is harmful, what reduces it?

It clears by itself, mainly in the urine after liver metabolism. In overdose there is no antidote specific to brompheniramine; the label describes effects ranging from central nervous system depression to stimulation, particularly in children, and management is supportive. Reducing the anticholinergic burden it adds means stopping or substituting it, which is a clinical decision. (Source 12)

Why might someone be low in it or missing it?

Does not apply. Brompheniramine maleate is a manufactured medicine, not a substance the body makes or requires, so there is no deficiency state. The only sense in which it can be absent is that someone is not taking it. (Source 21)

We searched: We searched PubMed and Europe PMC for brompheniramine deficiency and endogenous brompheniramine and found nothing, as expected for a synthetic drug.

Which whole foods contain it or feed it?

Does not apply. No whole food contains brompheniramine maleate. It reaches people only as a manufactured medicine, listed in US regulation as an OTC antihistamine active ingredient with a defined dose. (Source 21)

We searched: We searched PubMed and Europe PMC for dietary and natural sources of brompheniramine and found no reports of natural occurrence in food.

What happens if you do not have it?

Nothing happens that matters to health, because the body does not need it. For glue ear in children, going without it means avoiding a measurable excess of side effects for no measured benefit, since the pooled trial data showed no benefit and some harm. (Source 22)

How can you test for it?

There is no clinical test for it and no reason to have one. The label records basic pharmacokinetics, a peak plasma concentration about five hours after a 4 mg oral dose, but blood levels are a research and forensic measurement rather than something used to guide treatment, and we found no validated monitoring test or pharmacogenetic test for this drug. (Source 1)

We searched: We searched PubMed and Europe PMC for brompheniramine therapeutic drug monitoring, plasma assay and pharmacogenetics and found no validated clinical test.

References

1. DailyMed, US National Library of Medicine. Brompheniramine Maleate, Pseudoephedrine Hydrochloride and Dextromethorphan Hydrobromide Oral Syrup - prescribing information, Padagis US LLC, published 22 July 2026: CLINICAL PHARMACOLOGY section. 2026. Read the source
2. Annals of allergy, asthma & immunology : official publication of the American College of Allergy, Asthma, & Immunology. Brompheniramine, terfenadine, and placebo in allergic rhinitis - RESULTS section of the abstract. 1996. PMID 8933774, DOI 10.1016/S1081-1206(10)63334-0. Read the source
3. The Cochrane database of systematic reviews. Antihistamines for the common cold - AUTHORS' CONCLUSIONS section of the abstract. 2015. PMID 26615034, DOI 10.1002/14651858.CD009345.pub2. Read the source
4. The Cochrane database of systematic reviews. Antihistamines and/or decongestants for otitis media with effusion (OME) in children - MAIN RESULTS section of the abstract. 2011. PMID 21901683, DOI 10.1002/14651858.CD003423.pub3. Read the source
5. DailyMed, US National Library of Medicine. CVS PHARMACY CHILDRENS COLD AND ALLERGY (brompheniramine maleate) liquid - Drug Facts label, CVS Pharmacy Inc., published 17 August 2026 (SPL version 3). The Directions dose table is rebuilt cell by cell from the SPL XML: the label's own column heading cells, 'age' and 'Dose', are repeated as lead-ins before each cell, so every age band stays joined to its own dose and no cell boundary is lost.. 2026. Read the source
6. DailyMed, US National Library of Medicine. Brompheniramine Maleate, Pseudoephedrine Hydrochloride and Dextromethorphan Hydrobromide Oral Syrup - prescribing information, Padagis US LLC, published 22 July 2026: Drug Interactions subsection of PRECAUTIONS. 2026. Read the source
7. Journal of clinical pharmacology. Brompheniramine, loratadine, and placebo in allergic rhinitis: a placebo-controlled comparative clinical trial. 1998. PMID 9590467, DOI 10.1002/j.1552-4604.1998.tb04439.x. Read the source
8. British journal of clinical pharmacology. Repeated-dose effects of mequitazine, cetirizine and dexchlorpheniramine on driving and psychomotor performance - RESULTS section of the abstract. 2006. PMID 16390354, DOI 10.1111/j.1365-2125.2005.02524.x. Read the source
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10. DailyMed, US National Library of Medicine. Brompheniramine Maleate, Pseudoephedrine Hydrochloride and Dextromethorphan Hydrobromide Oral Syrup - prescribing information, Padagis US LLC, published 22 July 2026: WARNINGS section. 2026. Read the source
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