Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
QUIBRON-T/SR vs AMINOPHYLLIN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Theophylline is a methylxanthine that relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing intracellular c AMP, and antagonizing adenosine receptors.
Non-selective phosphodiesterase inhibitor, increasing intracellular c AMP and c GMP; adenosine receptor antagonist, causing bronchodilation, CNS stimulation, and positive chronotropic/inotropic effects.
Treatment of symptoms and prevention of asthma,Treatment of reversible bronchospasm associated with chronic bronchitis and emphysema
Treatment of acute bronchial asthma, reversible bronchospasm associated with chronic bronchitis and emphysema,Neonatal apnea (off-label),Adjunctive therapy in COPD exacerbations
200-400 mg orally every 12 hours; extended-release tablets. Initial dose 200 mg every 12 hours; may increase by 200 mg daily every 3-7 days based on serum theophylline levels (target 5-15 mcg/m L). Maximum 800 mg/day.
Loading dose: 6 mg/kg IV over 30 minutes (if not on theophylline); maintenance: 0.5-0.7 mg/kg/hr IV continuous infusion for adults (non-smoking), higher for smokers (0.7-0.9 mg/kg/hr). Oral: immediate-release 200-400 mg every 6 hours; sustained-release 400-600 mg every 12 hours.
Terminal t1/2: 3-12 hours (adults); 1-9 hours (children); prolonged in cirrhosis (up to 30 hours), heart failure, elderly. Clinical context: Narrow therapeutic index (5-15 mcg/m L); dosing interval adjusted based on t1/2.
Terminal elimination half-life: 3–12 hours in adults (mean ~6 hours); prolonged in hepatic impairment, heart failure, or COPD (up to 30 hours); shorter in smokers (4–5 hours due to CYP1A2 induction); neonates: 20–40 hours.
Hepatic via CYP1A2, CYP2E1, and CYP3A4; undergoes N-demethylation and oxidation. Saturable kinetics.
Hepatic demethylation and oxidation via cytochrome P450 isoenzymes (CYP1A2, CYP3A4, CYP2E1); approximately 10% excreted unchanged in urine.
Renal: ~10% unchanged; Hepatic metabolism (CYP1A2, CYP3A4): 90% to inactive metabolites (1,3-dimethyluric acid, 3-methylxanthine, 1-methyluric acid). Biliary/fecal: minimal (<5%).
Renal excretion of unchanged drug accounts for ~10%, with the remainder eliminated as metabolites (caffeine, 3-methylxanthine, 1-methyluric acid, 1,3-dimethyluric acid) via urine; minimal biliary/fecal elimination (<5%).
~40% bound to albumin. Binding is reversible and non-saturable.
~40% bound to plasma proteins (primarily albumin).
Vd: 0.3-0.7 L/kg (adults); approximates total body water. Increased Vd in premature infants and obesity; decreased in dehydration.
0.5 L/kg (range 0.3–0.7 L/kg); increased in neonates, cirrhosis, and malnutrition; reflects distribution into total body water.
Oral: 100% (immediate-release); 90-100% for SR formulations (dose-dependent slightly lower).
Oral (immediate-release): 100% (well absorbed); rectal: ~80% (variable); IV: 100%.
GFR >50 m L/min: no adjustment. GFR 10-50 m L/min: use 75% of normal dose, monitor levels. GFR <10 m L/min: use 50% of normal dose, monitor levels. Dose frequency unchanged.
GFR >50 m L/min: no adjustment; GFR 10-50 m L/min: reduce dose by 25% and monitor levels; GFR <10 m L/min: reduce dose by 50% and monitor levels closely.
Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%, monitor levels. Child-Pugh C: reduce dose by 70%, monitor levels. Use immediate-release forms preferred.
Child-Pugh A: reduce dose by 50%; Child-Pugh B: reduce dose by 75%; Child-Pugh C: use with extreme caution, reduce dose by 90% or consider alternative.
6-12 years: 10-16 mg/kg/day in divided doses every 12 hours (extended-release). 12-16 years: 12-18 mg/kg/day; target serum theophylline 5-15 mcg/m L. Maximum 800 mg/day.
Loading dose: 5-6 mg/kg IV over 30 minutes (if not on theophylline); maintenance: infants <1 year: 0.4-0.7 mg/kg/hr IV; children 1-9 years: 0.8-1.0 mg/kg/hr IV; children >9 years: 0.6-0.8 mg/kg/hr IV. Oral: immediate-release 5 mg/kg every 6 hours; sustained-release not recommended under 6 years.
Initiate at lower end of dosing (200-400 mg/day). Monitor serum concentrations due to decreased clearance. Avoid doses >400 mg/day without level monitoring. Titrate cautiously.
Reduce maintenance dose by 50-75% compared to younger adults; monitor serum theophylline levels closely; typical starting maintenance: 0.3-0.5 mg/kg/hr IV; avoid doses >400 mg/day oral.
No FDA black box warning.
No specific FDA boxed warning for aminophylline; however, theophylline (its active metabolite) has a narrow therapeutic index and requires serum concentration monitoring to avoid toxicity.
Seizures may occur at therapeutic levels,Use caution in patients with peptic ulcer, seizure disorders, cardiac arrhythmias,Monitor serum theophylline levels to avoid toxicity,Drug interactions with fluoroquinolones, cimetidine, macrolides, and allopurinol
Narrow therapeutic index; monitor serum concentrations (target 10-20 mcg/m L); caution in patients with peptic ulcer, hyperthyroidism, seizure disorders, cardiac arrhythmias; use with drugs that affect CYP1A2 (e.g., cimetidine, fluoroquinolones, fluvoxamine) or induce metabolism (e.g., smoking, rifampin, phenytoin).
Hypersensitivity to theophylline or any component,History of seizure disorder (relative),Active peptic ulcer disease (relative)
Hypersensitivity to aminophylline, theophylline, or ethylenediamine; active peptic ulcer disease; uncontrolled seizure disorders; severe cardiac arrhythmias (unless patient is undergoing monitored treatment).
Avoid charcoal-grilled meats and high-protein, low-carbohydrate diets which can decrease theophylline clearance. Caffeine-containing foods/beverages may potentiate adverse effects. Consistent dietary habits are recommended to maintain stable drug levels.
High-fat meals can delay absorption of aminophylline. Avoid charred meat and foods containing large amounts of caffeine. Cruciferous vegetables (broccoli, brussels sprouts) may increase metabolism. Maintain consistent dietary intake of protein and carbohydrates as changes can affect theophylline clearance.
Theophylline (active ingredient) is not teratogenic in humans. First trimester: No increased risk of major malformations from epidemiological studies. Second/third trimester: No specific fetal risks; however, high maternal serum levels may cause neonatal toxicity (jitteriness, tachycardia) if near term.
Aminophylline, a theophylline salt, is not teratogenic in humans. First trimester: No increased risk of major malformations. Second trimester: No specific fetal risks; maternal asthma control benefits outweigh risks. Third trimester: Risk of neonatal apnea, irritability, and tachycardia if maternal levels are high; avoid toxic levels.
Theophylline is excreted into breast milk with M/P ratio approximately 0.6-0.7. Relative infant dose is less than 10% of maternal weight-adjusted dose. Considered compatible with breastfeeding, but monitor infant for irritability or insomnia. Use lowest effective maternal dose.
Aminophylline is excreted into breast milk; the M/P ratio (milk-to-plasma ratio) is approximately 0.6-0.8. Infant exposure is low (about 1-10% of maternal weight-adjusted dose). Use with caution; monitor infant for irritability and sleep disturbance. Generally considered compatible with breastfeeding.
During pregnancy, theophylline clearance may decrease by 20-30% in third trimester due to reduced hepatic metabolism and increased volume of distribution. Monitor serum levels frequently and reduce dose by 10-20% if levels exceed therapeutic range; individualize dosing based on clinical response and drug monitoring.
Pregnancy reduces theophylline clearance by 30-50% due to decreased hepatic metabolism and increased volume of distribution. Dose adjustments may be needed: reduce dose by 30% in the third trimester or monitor serum concentrations closely to maintain therapeutic levels (5-15 mcg/m L). Postpartum, clearance returns to prepregnancy levels within 4-6 weeks; readjust accordingly.
Quibron-T/SR is a sustained-release theophylline formulation used for asthma and COPD. Monitor serum theophylline levels (therapeutic range 10-20 mcg/m L); levels >20 mcg/m L increase toxicity risk. Cimetidine, ciprofloxacin, and erythromycin decrease clearance, requiring dose reduction. Smoking induces metabolism, requiring higher doses. Use with caution in patients with heart failure, hepatic impairment, or fever.
Aminophylline is a bronchodilator composed of theophylline and ethylenediamine. The ethylenediamine component can cause hypersensitivity reactions. Monitor theophylline serum levels (target 10-20 mcg/m L). Use with caution in patients with cardiac arrhythmias, seizures, or peptic ulcer disease. Avoid in patients with porphyria. Cimetidine, ciprofloxacin, and macrolides can increase theophylline levels. Smoking induces metabolism, requiring higher doses.
Take exactly as prescribed; do not crush or chew sustained-release tablets.,Avoid excessive caffeine intake (coffee, tea, soda, chocolate) as it may increase side effects.,Report symptoms of toxicity: persistent nausea, vomiting, insomnia, rapid heartbeat, or seizures.,Do not stop abruptly; tapering may be needed.,Keep regular appointments for blood level monitoring.,Inform all healthcare providers of this medication.
Take this medication exactly as prescribed, with or without food.,Do not crush or chew extended-release formulations.,Avoid consuming large amounts of caffeine (coffee, tea, chocolate, energy drinks) as it may increase side effects.,Report symptoms such as rapid heart rate, persistent nausea/vomiting, insomnia, or seizures immediately.,Do not stop abruptly without consulting your doctor.,Keep a regular dosing schedule to maintain consistent blood levels.
No interactions on record
"Concurrent administration of aminophylline, a xanthine derivative bronchodilator that is metabolized primarily by CYP1A2 and to a lesser extent CYP3A4, may reduce the clearance of ranolazine, an antianginal agent predominantly metabolized by CYP3A4 and to a lesser extent CYP2D6. Aminophylline can inhibit CYP3A4 activity, leading to increased ranolazine plasma concentrations, which elevates the risk of dose-dependent adverse effects such as QTc prolongation, dizziness, and syncope. This interaction is clinically significant and may necessitate dose adjustment or alternative therapy."
"Asunaprevir, a potent inhibitor of the drug transporter OATP1B1, can significantly decrease the serum concentration of aminophylline, a theophylline salt, likely by reducing its intestinal absorption or increasing its hepatic clearance. This interaction may lead to reduced therapeutic efficacy of aminophylline, potentially worsening respiratory symptoms in patients with asthma or COPD. Close monitoring and dose adjustment of aminophylline are recommended during coadministration with asunaprevir."
"Aminophylline, a bronchodilator, inhibits the metabolism of tibolone, a synthetic steroid hormone used for hormone replacement therapy, primarily through competitive inhibition of cytochrome P450 (CYP) 3A4 isoenzyme. This results in increased plasma concentrations of tibolone and its active metabolites, potentiating its hormonal effects and increasing the risk of adverse events such as thromboembolism, endometrial hyperplasia, or breast tenderness. Clinically, coadministration may require dose adjustments and careful monitoring for signs of estrogenic excess."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about QUIBRON-T/SR vs AMINOPHYLLIN, answered by our medical review team.
QUIBRON-T/SR is a Xanthine Bronchodilator that works by Theophylline is a methylxanthine that relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing intracellular c AMP, and antagonizing adenosine receptors.. AMINOPHYLLIN is a Xanthine Bronchodilator that works by Non-selective phosphodiesterase inhibitor, increasing intracellular c AMP and c GMP; adenosine receptor antagonist, causing bronchodilation, CNS stimulation, and positive chronotropic/inotropic effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between QUIBRON-T/SR and AMINOPHYLLIN depend on the specific clinical indication. These are both Xanthine Bronchodilator agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of QUIBRON-T/SR is: 200-400 mg orally every 12 hours; extended-release tablets. Initial dose 200 mg every 12 hours; may increase by 200 mg daily every 3-7 days based on serum theophylline levels (target 5-15 mcg/m L). Maximum 800 mg/day.. The standard adult dose of AMINOPHYLLIN is: Loading dose: 6 mg/kg IV over 30 minutes (if not on theophylline); maintenance: 0.5-0.7 mg/kg/hr IV continuous infusion for adults (non-smoking), higher for smokers (0.7-0.9 mg/kg/hr). Oral: immediate-release 200-400 mg every 6 hours; sustained-release 400-600 mg every 12 hours.. 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 QUIBRON-T/SR and AMINOPHYLLIN 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. QUIBRON-T/SR is classified as Category C. Theophylline (active ingredient) is not teratogenic in humans. First trimester: No increased risk of major malformations from epidemiological studies. Second/third trimester: No sp. AMINOPHYLLIN is classified as Category C. Aminophylline, a theophylline salt, is not teratogenic in humans. First trimester: No increased risk of major malformations. Second trimester: No specific fetal risks; maternal ast. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.