Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
PHYLLOCONTIN vs ELIXICON
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Sustained-release theophylline; nonselective phosphodiesterase (PDE) inhibitor, adenosine receptor antagonist, and histone deacetylase activator. Bronchodilation via relaxation of bronchial smooth muscle; also reduces airway hyperresponsiveness and inflammation.
Theophylline is a xanthine derivative that inhibits phosphodiesterase, leading to increased intracellular cyclic AMP levels. It also acts as a nonselective adenosine receptor antagonist, resulting in bronchodilation and anti-inflammatory effects.
Treatment of asthma (maintenance therapy),Chronic obstructive pulmonary disease (COPD) maintenance therapy
Treatment of symptoms and reversible airflow obstruction associated with chronic asthma,Management of chronic obstructive pulmonary disease (COPD),Off-label: Apnea of prematurity
For chronic obstructive pulmonary disease and asthma: initial dose 225 mg orally twice daily; may increase to 450 mg twice daily. Based on theophylline, target serum concentration 5-15 mcg/m L.
400 mg orally every 6 hours or 600 mg orally every 8 hours; extended-release: 600-1200 mg orally every 12 hours.
Terminal elimination half-life: 3-8 hours in non-smoking adults; reduced to 1.5-5 hours in smokers; prolonged to 10-30 hours in heart failure or hepatic cirrhosis.
Terminal elimination half-life: 4-6 hours in adults; 3-4 hours in children; prolonged in hepatic impairment or congestive heart failure. Context: dosing interval adjustment required in these conditions.
Primarily hepatic via CYP1A2, with minor contributions from CYP2E1 and CYP3A4. Metabolites: 1,3-dimethyluric acid, 3-methylxanthine, and 1-methyluric acid.
Primarily hepatic metabolism via cytochrome P450 1A2 (CYP1A2). Minor pathways include CYP2E1 and CYP3A4. Metabolites are excreted renally.
Renal: approximately 10% unchanged; hepatic metabolism accounts for ~90% of clearance; metabolites eliminated renally.
Renal: 50% unchanged; hepatic metabolism to 3-methylxanthine, theophylline, etc. Biliary/fecal: minimal.
Approximately 40-60% bound, primarily to albumin.
Approximately 40% bound, primarily to albumin.
0.45 L/kg (range 0.3-0.7 L/kg), approximating total body water; increased in neonates and cirrhosis.
Vd: 0.3-0.5 L/kg; indicates distribution into total body water, minimal tissue binding.
Oral immediate-release: 96-100%; sustained-release: 90-100%; rectal: approximately 80-90%.
Oral immediate-release: 100%; Extended-release: 100% (well-absorbed, no first-pass metabolism).
GFR < 30 m L/min: reduce dose by 50% and monitor serum levels; avoid use if possible due to accumulation risk.
GFR > 50 m L/min: no adjustment; GFR 10-50 m L/min: reduce dose by 25-50% and monitor theophylline levels; GFR < 10 m L/min: reduce dose by 50% and monitor levels.
Child-Pugh Class A: reduce dose by 50%; Child-Pugh Class B: reduce dose by 75%; Child-Pugh Class C: contraindicated. Monitor serum levels closely.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce dose by 50%; Child-Pugh Class C: reduce dose by 75% and monitor levels.
Weight-based dosing (theophylline): 10-16 mg/kg/day orally divided every 6-12 hours; individualize based on serum levels (target 5-10 mcg/m L). Use immediate-release formulations; sustained-release not recommended.
Initial: 5 mg/kg/dose orally every 6 hours; maintenance: 100-400 mg/day in divided doses; monitor levels aggressively.
Lower initial doses (e.g., 112.5 mg twice daily) due to decreased clearance; monitor serum levels and adjust to target 5-10 mcg/m L. Avoid in elderly with cardiac arrhythmias or seizures.
Start at lowest effective dose (e.g., 200 mg orally every 12 hours) due to reduced clearance; monitor theophylline levels and adjust based on response and tolerability.
No FDA boxed warning.
Theophylline has a narrow therapeutic index; plasma levels should be monitored to avoid toxicity. Dosage should be individualized based on steady-state serum concentrations. Concurrent illness, fever, or changes in smoking habits can alter theophylline clearance.
Narrow therapeutic index; monitor serum theophylline levels. Risk of toxicity (seizures, arrhythmias) at high doses. Caution in patients with peptic ulcer, seizure disorders, cardiac disease, hepatic impairment, or in elderly. Drug interactions (CYP1A2 inducers/inhibitors).
Risk of seizures at high serum levels; may induce or worsen arrhythmias; use with caution in patients with peptic ulcer disease, hyperthyroidism, or seizure disorders; drug interactions with cimetidine, fluoroquinolones, macrolides, and allopurinol can increase theophylline levels.
Hypersensitivity to theophylline; pre-existing cardiac arrhythmias (unless appropriate monitoring); active peptic ulcer disease.
Hypersensitivity to theophylline or any component of the formulation; pre-existing cardiac arrhythmias (e.g., tachyarrhythmias); active seizure disorder.
Avoid high-protein or charcoal-broiled foods, as they can decrease theophylline levels. Caffeine-containing foods and beverages (e.g., coffee, tea, cola, chocolate) may increase theophylline levels and toxicity risk. Consistent dietary habits are important to maintain stable serum levels.
Avoid large amounts of caffeine-containing foods and beverages such as coffee, tea, cola, and chocolate as they may increase side effects like jitteriness and insomnia. High-fat meals may affect absorption; take consistently with respect to meals. Charcoal-broiled foods may increase metabolism of theophylline, reducing efficacy.
Teratogenic risk profile: Theophylline (active ingredient in Phyllocontin) is Pregnancy Category C. First trimester: Limited data suggest no major teratogenic risk, but animal studies show potential fetal toxicity at high doses. Second and third trimesters: Theophylline crosses the placenta; fetal serum levels approximate maternal levels. Adverse effects include fetal tachycardia, jitteriness, and neonatal respiratory distress. Risk of neonatal apnea and withdrawal symptoms at delivery.
Insufficient human data; animal studies show fetal toxicity at high doses. Avoid in first trimester unless benefit outweighs risk. Second and third trimester: use only if clearly needed.
Lactation summary: Theophylline is excreted into breast milk with an M/P ratio of approximately 0.7. Infant serum levels can reach 1-10% of maternal levels. Monitor infant for irritability, insomnia, and feeding difficulties. Generally considered compatible with breastfeeding if maternal levels are therapeutic; avoid high doses.
Excreted into breast milk; M/P ratio unknown. Caution advised, monitor infant for adverse effects.
Dosing adjustments in pregnancy: Pregnancy increases the volume of distribution and decreases hepatic clearance of theophylline, leading to reduced serum levels. Dose may need to be increased by 20-30% in the second and third trimesters. Monitor serum levels frequently and adjust to maintain therapeutic range. Postpartum, clearance returns to prepregnancy levels rapidly; reduce dose accordingly.
Increased clearance during pregnancy may require dose adjustment; monitor therapeutic levels.
PHYLLOCONTIN (sustained-release theophylline) is a bronchodilator with a narrow therapeutic index (5-15 mcg/m L). Monitor trough levels before dose escalation. Cigarette smoking, phenytoin, and rifampin induce metabolism, requiring dose increases. Conversely, cimetidine, ciprofloxacin, and fluvoxamine inhibit metabolism, necessitating dose reductions. Use with caution in hepatic impairment, heart failure, and elderly patients due to reduced clearance.
ELIXICON (theophylline) requires therapeutic drug monitoring due to narrow therapeutic index of 10-20 mcg/m L. Avoid in patients with active peptic ulcer disease or seizure disorders. Use with caution in heart failure, liver disease, and elderly patients due to reduced clearance. Cigarette smoking induces metabolism, requiring dose adjustments. Common side effects include nausea, vomiting, and insomnia; toxicity presents with tachycardia, seizures, or ventricular arrhythmias.
Take this medication exactly as prescribed, usually every 12 hours, with or without food.,Do not crush or chew the extended-release tablets; swallow them whole.,Avoid smoking and avoid changing your smoking habits while on this medication, as it affects the drug level.,Limit or avoid caffeine-containing products (coffee, tea, cola, chocolate) as they may increase side effects.,Report symptoms of toxicity such as nausea, vomiting, insomnia, jitteriness, or rapid heartbeat to your healthcare provider immediately.,Do not change your dose or stop taking this medication without consulting your doctor.
Take exactly as prescribed and do not change dose without consulting your doctor.,Avoid smoking and second-hand smoke as it affects how the medication works.,Limit caffeine intake (coffee, tea, chocolate, cola) as it may increase side effects.,Report symptoms of toxicity: persistent nausea, vomiting, rapid heart rate, or seizures.,Do not take this medication with other cold or asthma remedies without medical advice.
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 PHYLLOCONTIN vs ELIXICON, answered by our medical review team.
PHYLLOCONTIN is a Xanthine Bronchodilator that works by Sustained-release theophylline; nonselective phosphodiesterase (PDE) inhibitor, adenosine receptor antagonist, and histone deacetylase activator. Bronchodilation via relaxation of bronchial smooth muscle; also reduces airway hyperresponsiveness and inflammation.. ELIXICON is a Xanthine Bronchodilator that works by Theophylline is a xanthine derivative that inhibits phosphodiesterase, leading to increased intracellular cyclic AMP levels. It also acts as a nonselective adenosine receptor antagonist, resulting in bronchodilation and anti-inflammatory effects.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between PHYLLOCONTIN and ELIXICON 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 PHYLLOCONTIN is: For chronic obstructive pulmonary disease and asthma: initial dose 225 mg orally twice daily; may increase to 450 mg twice daily. Based on theophylline, target serum concentration 5-15 mcg/m L.. The standard adult dose of ELIXICON is: 400 mg orally every 6 hours or 600 mg orally every 8 hours; extended-release: 600-1200 mg orally 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 PHYLLOCONTIN and ELIXICON 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. PHYLLOCONTIN is classified as Category C. Teratogenic risk profile: Theophylline (active ingredient in Phyllocontin) is Pregnancy Category C. First trimester: Limited data suggest no major teratogenic risk, but animal stud. ELIXICON is classified as Category C. Insufficient human data; animal studies show fetal toxicity at high doses. Avoid in first trimester unless benefit outweighs risk. Second and third trimester: use only if clearly n. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.