Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DISOPHROL vs BONTRIL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Disophrol is a combination of dexbrompheniramine, a first-generation antihistamine that blocks H1 receptors, and pseudoephedrine, a sympathomimetic amine that stimulates alpha-adrenergic receptors causing vasoconstriction.
Bontril (phendimetrazine) is a sympathomimetic amine that acts as an appetite suppressant. Its mechanism involves stimulating the hypothalamus to release norepinephrine and dopamine, which reduces hunger cues. It is a prodrug that is metabolized to the active agent phenmetrazine, which inhibits reuptake and increases release of norepinephrine and dopamine in the central nervous system.
Relief of symptoms of seasonal or perennial allergic rhinitis,Relief of symptoms of vasomotor rhinitis,Relief of nasal congestion associated with the common cold,Relief of sinusitis symptoms
FDA-approved for management of obesity as a short-term adjunct (few weeks) in a regimen of weight reduction based on caloric restriction, exercise, and behavior modification. Off-label uses are not well documented due to limited evidence.
1 tablet (6 mg dexbrompheniramine maleate / 60 mg pseudoephedrine sulfate) orally every 4-6 hours; not to exceed 4 tablets in 24 hours.
BONTRIL 50 mg orally once daily, with or without food.
Terminal elimination half-life is 3-4 hours in adults; in renal impairment, half-life may be prolonged up to 8-12 hours requiring dose adjustment.
18-24 hours; prolonged in renal impairment (up to 40 hours) requiring dose adjustment.
Dexbrompheniramine is metabolized in the liver primarily via CYP450 enzymes; pseudoephedrine is partially metabolized in the liver by N-demethylation and excreted largely unchanged in urine.
Phendimetrazine is extensively metabolized in the liver, primarily via N-demethylation to its active metabolite phenmetrazine. Minor pathways include hydroxylation and conjugation. Cytochrome P450 enzymes are involved, though specific isoforms are not fully characterized.
Renal excretion of unchanged drug and metabolites; approximately 60-70% of a dose eliminated in urine as unchanged drug and glucuronide conjugates, with <10% in feces.
Primarily renal (60-70% unchanged) with minor biliary/fecal (10-15% as metabolites).
Approximately 50-60% bound to plasma proteins, primarily albumin.
85-90% bound to albumin and alpha-1-acid glycoprotein.
Volume of distribution is approximately 1.5-2.5 L/kg, indicating extensive tissue distribution.
3-5 L/kg; indicates extensive tissue distribution.
Oral bioavailability is about 70-80% due to first-pass metabolism.
Oral: 70-80% (first-pass metabolism); IV: 100%.
GFR 30-50 m L/min: administer every 6-8 hours. GFR 15-29 m L/min: administer every 12 hours. GFR <15 m L/min: not recommended.
GFR >60 m L/min: no adjustment. GFR 30-60 m L/min: reduce dose to 25 mg once daily. GFR <30 m L/min: use is not recommended.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: use with caution, reduce dose frequency. Child-Pugh Class C: contraindicated.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose to 25 mg once daily. Child-Pugh Class C: use is contraindicated.
Children 6-11 years: 1/2 tablet (3 mg dexbrompheniramine / 30 mg pseudoephedrine) orally every 4-6 hours, max 2 tablets per day. Children <6 years: not recommended.
Weight-based: 1 mg/kg orally once daily, with a maximum of 50 mg. Not recommended for children weighing less than 10 kg.
Initiate with 1/2 tablet every 6-8 hours; monitor for anticholinergic effects and hypertension; avoid in patients >65 years due to increased risk of adverse effects.
Start at 25 mg orally once daily; may increase to 50 mg after 2 weeks if tolerated and renal function is adequate (Cr Cl >60 m L/min).
None.
None
Cardiovascular effects: may cause hypertension, palpitations, arrhythmias,Central nervous system stimulation: may cause insomnia, dizziness, tremor,Urinary retention: use with caution in patients with BPH or urinary obstruction,Increased intraocular pressure: avoid in narrow-angle glaucoma,Elderly patients: more sensitive to anticholinergic and cardiovascular effects
Risk of abuse, dependence, and tolerance; monitor for signs of addiction.,May cause serious cardiovascular events including pulmonary hypertension and valvular heart disease, especially with long-term use.,May impair ability to drive or operate machinery due to dizziness or blurred vision.,Use with caution in patients with hypertension, hyperthyroidism, glaucoma, or history of drug abuse.,Concomitant use with other sympathomimetics or MAO inhibitors can cause hypertensive crisis.,Not recommended for use in patients with a history of epilepsy or those taking other anorectic agents.
Severe hypertension,Coronary artery disease,Concurrent use of MAO inhibitors or within 14 days of such therapy,Narrow-angle glaucoma,Urinary retention,Severe renal impairment,Hypersensitivity to any component
Known hypersensitivity to phendimetrazine or any component of the formulation.,History of cardiovascular disease including coronary artery disease, arrhythmias, or congestive heart failure.,Hypertension (moderate to severe).,Hyperthyroidism.,Glaucoma.,History of drug abuse or alcoholism.,Concurrent use of monoamine oxidase inhibitors or within 14 days of such use.,Pregnancy and breastfeeding.,Agitated states.,History of seizure disorders.
Avoid consuming alcohol while taking Disophrol. Caffeine may increase restlessness and insomnia. There is no specific food interaction, but taking with food may reduce gastrointestinal upset.
Avoid high-fat meals as they may delay absorption of oral formulations. No specific food-drug interactions known; however, anticholinergic effects may be exacerbated by alcohol.
DISOPHROL (dexchlorpheniramine/pseudoephedrine) is classified as FDA Pregnancy Category C. First trimester: Case reports suggest a possible small increased risk of gastroschisis with antihistamine use, but data are limited; pseudoephedrine may be associated with a small risk of gastroschisis and hemifacial microsomia. Second and third trimesters: No specific fetal risks have been clearly established; pseudoephedrine may cause fetal tachycardia and decreased uterine blood flow at high doses. Avoid in third trimester due to potential for uterine contraction inhibition and neonatal respiratory depression from antihistamines.
BONTRIL is classified as FDA Pregnancy Category X. First trimester: high risk of major congenital malformations including neural tube defects, cardiovascular anomalies, and cleft palate. Second and third trimesters: risk of fetal growth restriction, oligohydramnios, and neonatal respiratory depression if used near term.
DISOPHROL is excreted into breast milk. Dexchlorpheniramine: Present in low levels, M/P ratio not established; may cause irritability and drowsiness in infants. Pseudoephedrine: Excreted into breast milk with M/P ratio of approximately 2.6-3.5; may cause infant irritability and decreased milk production. Use caution and monitor infant for excessive drowsiness or irritability.
No data available on excretion into human breast milk. M/P ratio unknown. Due to potential for serious adverse effects in nursing infants, breastfeeding is contraindicated during BONTRIL therapy.
No specific dose adjustments are recommended in pregnancy; however, use lowest effective dose and shortest duration. Due to increased plasma volume and renal clearance in pregnancy, pseudoephedrine may have reduced efficacy; dose may need empirical adjustment based on response. Avoid extended-release formulations in pregnancy.
No dose adjustment required for pregnancy. However, due to teratogenicity, BONTRIL should be discontinued before conception or as soon as pregnancy is diagnosed.
Disophrol combines an antihistamine (dexbrompheniramine) and a decongestant (pseudoephedrine). Avoid in patients with hypertension, coronary artery disease, or hyperthyroidism due to pseudoephedrine's sympathomimetic effects. Monitor for anticholinergic side effects (drowsiness, dry mouth) from the antihistamine component. Use with caution in glaucoma, urinary retention, and prostatic hypertrophy.
BONTRIL (hyoscyamine) is an anticholinergic used for GI spasms; avoid in patients with glaucoma, myasthenia gravis, or obstructive uropathy. Onset of action is 2-3 minutes IV; monitor for heat stroke in high ambient temperatures due to decreased sweating.
Take this medication as prescribed; do not exceed recommended dose due to risk of serious side effects.,Avoid alcohol and other CNS depressants as they may increase drowsiness.,Do not take with other medications containing decongestants or antihistamines.,Notify your doctor if you have high blood pressure, heart disease, glaucoma, or difficulty urinating.,May cause drowsiness; avoid driving or operating heavy machinery until you know how it affects you.
Do not drive or operate machinery until you know how this medication affects you, as it may cause dizziness or blurred vision.,Avoid alcohol and other CNS depressants as they may increase sedation.,Report immediately if you experience eye pain, difficulty urinating, or rapid heartbeat.,Use caution in hot weather; this drug reduces sweating and increases risk of heat stroke.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about DISOPHROL vs BONTRIL, answered by our medical review team.
DISOPHROL is a Antihistamine/Decongestant Combination that works by Disophrol is a combination of dexbrompheniramine, a first-generation antihistamine that blocks H1 receptors, and pseudoephedrine, a sympathomimetic amine that stimulates alpha-adrenergic receptors causing vasoconstriction.. BONTRIL is a Sympathomimetic Anorectic that works by Bontril (phendimetrazine) is a sympathomimetic amine that acts as an appetite suppressant. Its mechanism involves stimulating the hypothalamus to release norepinephrine and dopamine, which reduces hunger cues. It is a prodrug that is metabolized to the active agent phenmetrazine, which inhibits reuptake and increases release of norepinephrine and dopamine in the central nervous system.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between DISOPHROL and BONTRIL depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of DISOPHROL is: 1 tablet (6 mg dexbrompheniramine maleate / 60 mg pseudoephedrine sulfate) orally every 4-6 hours; not to exceed 4 tablets in 24 hours.. The standard adult dose of BONTRIL is: BONTRIL 50 mg orally once daily, with or without food.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between DISOPHROL and BONTRIL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. DISOPHROL is classified as Category C. DISOPHROL (dexchlorpheniramine/pseudoephedrine) is classified as FDA Pregnancy Category C. First trimester: Case reports suggest a possible small increased risk of gastroschisis wi. BONTRIL is classified as Category C. BONTRIL is classified as FDA Pregnancy Category X. First trimester: high risk of major congenital malformations including neural tube defects, cardiovascular anomalies, and cleft p. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.