Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ADVIL ALLERGY AND CONGESTION RELIEF vs FASTIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis, which mediates inflammation, pain, and fever. Pseudoephedrine is a sympathomimetic amine that acts as a decongestant by stimulating alpha-adrenergic receptors in the nasal mucosa, causing vasoconstriction.
Sympathomimetic amine that promotes release of norepinephrine and dopamine from presynaptic nerve terminals in the hypothalamus, suppressing appetite.
Temporary relief of symptoms due to hay fever or other upper respiratory allergies: nasal congestion, sinus pressure, sneezing, runny nose, itching of nose or throat, and itchy, watery eyes due to allergies.,Temporary reduction of fever.,Relief of minor aches and pains associated with the common cold, headache, toothache, muscular aches, backache, menstrual cramps, and arthritis pain.
Short-term adjunct in exogenous obesity,Off-label: Attention deficit hyperactivity disorder (ADHD)
Ibuprofen 200 mg and pseudoephedrine HCl 30 mg per tablet. Usual adult dose: 1-2 tablets orally every 4-6 hours as needed, not to exceed 6 tablets in 24 hours.
30 mg orally once daily in the morning, administered as a single dose.
Ibuprofen: 2-4 hours; pseudoephedrine: 5-8 hours. Shorter half-life requires frequent dosing for sustained relief.
Terminal elimination half-life is approximately 16-20 hours for the immediate-release formulation. With sustained-release forms, effective half-life may extend to 24-34 hours due to prolonged absorption. Clinical context: time to reach steady state is about 3-5 days.
Ibuprofen is primarily metabolized by cytochrome P450 (CYP) enzymes, mainly CYP2C9, to inactive metabolites (hydroxyibuprofen and carboxyibuprofen). Pseudoephedrine is partially metabolized in the liver by N-demethylation to an inactive metabolite.
Hepatic metabolism via CYP3A4 and CYP2D6; active metabolite phendimetrazine (for some formulations).
Renal excretion of unchanged drug and metabolites; approximately 1% excreted unchanged (pseudoephedrine) and 15% (ibuprofen). Biliary/fecal elimination accounts for <5%.
Primarily renal (approximately 70-80% unchanged) and biliary/fecal (20-30% as metabolites). Urinary excretion is p H-dependent; acidic urine increases elimination.
Ibuprofen: 99% bound to albumin; pseudoephedrine: negligible protein binding.
Approximately 40-50% bound to plasma proteins (albumin).
Ibuprofen: 0.1-0.2 L/kg; pseudoephedrine: 2.5-3 L/kg.
Approximately 3-5 L/kg. High Vd indicates extensive tissue distribution, including brain.
Oral: ibuprofen 80-100%; pseudoephedrine 100%.
Oral immediate-release: ~90% (high first-pass metabolism; absolute bioavailability is lower, but systemic exposure is adequate). Oral sustained-release: similar extent but with prolonged absorption.
For pseudoephedrine: Cr Cl <30 m L/min, reduce dose by 50% or administer every 12 hours. For ibuprofen: avoid use if Cr Cl <30 m L/min; if Cr Cl 30-59 m L/min, use lowest effective dose and monitor renal function.
Contraindicated in severe renal impairment (e GFR <30 m L/min/1.73 m²). For moderate impairment (e GFR 30-59 m L/min/1.73 m²), reduce dose to 15 mg once daily.
For ibuprofen: Child-Pugh class A and B: no adjustment necessary; Child-Pugh class C: avoid use. For pseudoephedrine: use with caution in severe hepatic impairment; no specific dose adjustment recommended, but monitor for adverse effects.
Contraindicated in Child-Pugh class C cirrhosis. In Child-Pugh class A or B, initiate at 15 mg once daily and titrate cautiously to maximum 30 mg once daily.
Not indicated for children under 12 years of age. For children 12 years and older: same as adult dose (1-2 tablets every 4-6 hours, max 6 tablets per day). Weight-based: not routinely used; safety and efficacy not established for <25 kg.
Not recommended for pediatric patients under 16 years of age due to lack of safety and efficacy data.
For ibuprofen: use lowest effective dose for shortest duration; monitor renal function and GI bleeding risk. For pseudoephedrine: initiate at lower doses (e.g., one tablet every 6 hours) due to increased sensitivity and risk of hypertension, urinary retention, and CNS effects.
Initiating at 15 mg once daily is recommended due to increased sensitivity and potential for central nervous system adverse effects; maximum dose 30 mg once daily.
Cardiovascular risk: NSAIDs may increase the risk of serious cardiovascular thrombotic events, myocardial infarction, and stroke, which can be fatal. Risk increases with duration of use and in patients with cardiovascular risk factors. Contraindicated for perioperative pain in coronary artery bypass graft (CABG) surgery. Gastrointestinal risk: NSAIDs increase the risk of serious gastrointestinal adverse events including bleeding, ulceration, and perforation of the stomach or intestines, which can be fatal. Elderly patients and those with prior peptic ulcer disease and/or GI bleeding are at greater risk.
None.
Cardiovascular effects: may increase risk of heart attack or stroke; use lowest effective dose for shortest duration. Gastrointestinal effects: may cause GI ulceration, bleeding, perforation. Renal effects: avoid in advanced renal disease; monitor renal function. Hepatic effects: may cause liver enzyme elevation; discontinue if liver disease develops. Anaphylactic reactions: may occur in patients with or without prior NSAID sensitivity. Asthma: may cause bronchospasm. Hypertension: may worsen hypertension. Avoid in late pregnancy due to risk of premature closure of ductus arteriosus. Pseudoephedrine: may cause nervousness, dizziness, insomnia, hypertension, arrhythmias; use with caution in patients with cardiovascular disease, diabetes, glaucoma, prostatic hypertrophy, hyperthyroidism. Avoid in severe hypertension or coronary artery disease.
Cardiovascular events (hypertension, tachycardia, stroke), psychiatric adverse effects (psychosis, dependence), primary pulmonary hypertension, valvular heart disease, tolerance, withdrawal symptoms, glaucoma, hyperthyroidism, seizure disorder, diabetes (dose adjustment required), elderly patients (higher sensitivity).
Hypersensitivity to ibuprofen, pseudoephedrine, or any component of the formulation. History of asthma, urticaria, or allergic-type reaction after taking aspirin or other NSAIDs. In the setting of coronary artery bypass graft (CABG) surgery. Severe hypertension. Coronary artery disease. Concurrent use with or within 14 days of monoamine oxidase inhibitors (MAOIs) due to risk of hypertensive crisis. Pregnancy (third trimester).
Cardiovascular disease (e.g., coronary artery disease, arrhythmias, hypertension), hyperthyroidism, glaucoma, agitated states, history of drug abuse, MAOIs (concurrent or within 14 days), hypersensitivity to sympathomimetics.
Take with food or milk to minimize GI upset. Avoid alcohol as it may increase risk of GI bleeding. No specific food-drug interactions.
Avoid excessive caffeine intake (e.g., coffee, tea, cola, energy drinks) as it may potentiate CNS and cardiovascular effects. Grapefruit juice may alter drug metabolism; avoid concurrent consumption. Maintain a balanced, reduced-calorie diet as part of the weight loss plan. Alcohol should be avoided due to potential additive CNS effects.
First trimester: Possible increased risk of cardiovascular malformations and gastroschisis with NSAID use. Second trimester: No specific malformation risk reported, but avoid prolonged use due to potential oligohydramnios. Third trimester: NSAIDs (including ibuprofen) are contraindicated due to risk of premature ductus arteriosus closure and oligohydramnios. Pseudoephedrine: Limited data; possible association with gastroschisis if used in first trimester; avoid due to vasoconstrictive effects.
FDA Pregnancy Category X. First trimester: Increased risk of oral clefts and cardiac malformations with amphetamine use. Second and third trimesters: Risk of premature delivery, low birth weight, and neonatal withdrawal syndrome. Avoid use in pregnancy.
Ibuprofen: Excreted in low levels (M/P ratio ~0.006); considered compatible with breastfeeding. Pseudoephedrine: Excreted in breast milk (M/P ratio ~2.5-3.5); may reduce milk production and cause irritability in infants; use with caution.
Excreted in human milk; M/P ratio not established. Potential for adverse effects in nursing infants (irritability, poor feeding). Contraindicated during breastfeeding.
Ibuprofen: No specific dose adjustment recommended for pregnancy; however, avoid use in third trimester. Pseudoephedrine: No dose adjustment studied; use lowest effective dose for shortest duration. Neither drug is recommended for regular use during pregnancy.
Contraindicated in pregnancy; no dose adjustments recommended.
Combination of ibuprofen (NSAID) and pseudoephedrine (decongestant). Ibuprofen may increase blood pressure, counteracting pseudoephedrine's vasoconstriction; monitor in hypertensive patients. Avoid in patients with severe CAD, uncontrolled HTN, or within 2 weeks of MAOI use.
Fastin (phentermine) is a sympathomimetic amine indicated for short-term (up to 12 weeks) monotherapy for obesity. It should be used in conjunction with a reduced-calorie diet and exercise. Avoid co-administration with MAOIs or within 14 days of MAOI use due to hypertensive crisis risk. Use with caution in patients with hypertension, diabetes, or history of drug abuse. Monitor blood pressure and heart rate regularly. Tachyphylaxis may develop; discontinue if tolerance occurs. Do not use in patients with advanced arteriosclerosis, hyperthyroidism, glaucoma, or agitated states.
Do not take with other NSAIDs or cold/flu products to avoid overdose.,Pseudoephedrine may cause insomnia; take last dose at least 4-6 hours before bedtime.,Ibuprofen can cause GI bleeding; take with food or milk to reduce risk.,Stop use and consult doctor if symptoms persist >7 days or if fever lasts >3 days.,Avoid alcohol while taking this medication.
Take Fastin exactly as prescribed, usually once daily in the morning to avoid insomnia.,Do not crush or chew the extended-release capsule; swallow whole.,Avoid taking late in the day to prevent difficulty sleeping.,Report any chest pain, palpitations, shortness of breath, or dizziness immediately.,Do not increase dose or take more frequently than prescribed; risk of dependence and side effects.,Fastin is for short-term use only (up to 12 weeks) and should be combined with a reduced-calorie diet and exercise.,Do not use if you have taken an MAO inhibitor in the last 14 days.,Avoid alcohol and other CNS stimulants (e.g., caffeine in large amounts) as they may increase side effects.,Do not stop abruptly; follow your doctor's instructions for tapering off.,Keep out of reach of children; misuse can cause severe cardiac toxicity.
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 ADVIL ALLERGY AND CONGESTION RELIEF vs FASTIN, answered by our medical review team.
ADVIL ALLERGY AND CONGESTION RELIEF is a NSAID/Decongestant Combination that works by Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis, which mediates inflammation, pain, and fever. Pseudoephedrine is a sympathomimetic amine that acts as a decongestant by stimulating alpha-adrenergic receptors in the nasal mucosa, causing vasoconstriction.. FASTIN is a Sympathomimetic Anorectic that works by Sympathomimetic amine that promotes release of norepinephrine and dopamine from presynaptic nerve terminals in the hypothalamus, suppressing appetite.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ADVIL ALLERGY AND CONGESTION RELIEF and FASTIN 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 ADVIL ALLERGY AND CONGESTION RELIEF is: Ibuprofen 200 mg and pseudoephedrine HCl 30 mg per tablet. Usual adult dose: 1-2 tablets orally every 4-6 hours as needed, not to exceed 6 tablets in 24 hours.. The standard adult dose of FASTIN is: 30 mg orally once daily in the morning, administered as a single dose.. 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 ADVIL ALLERGY AND CONGESTION RELIEF and FASTIN 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. ADVIL ALLERGY AND CONGESTION RELIEF is classified as Category C. First trimester: Possible increased risk of cardiovascular malformations and gastroschisis with NSAID use. Second trimester: No specific malformation risk reported, but avoid prolo. FASTIN is classified as Category C. FDA Pregnancy Category X. First trimester: Increased risk of oral clefts and cardiac malformations with amphetamine use. Second and third trimesters: Risk of premature delivery, lo. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.