THEOLIXIR
Clinical safety rating
cautionComprehensive clinical and safety monograph for THEOLIXIR (THEOLIXIR).
Theophylline is a xanthine derivative that acts as a competitive nonselective phosphodiesterase inhibitor, increasing intracellular cyclic AMP levels, and as an antagonist at adenosine receptors (A1 and A2 subtypes), leading to bronchodilation, anti-inflammatory effects, and stimulation of respiratory drive.
| Metabolism | Hepatic metabolism via CYP1A2, CYP2E1, and CYP3A4. Approximately 10% excreted unchanged in urine. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 10% of elimination; the remainder is hepatically metabolized, with 80% excreted in urine as metabolites (1-methyluric acid and 3-methylxanthine) and less than 10% in feces. |
| Half-life | Terminal elimination half-life is 3–5 hours in adults (nonsmokers), but prolonged to 6–8 hours in neonates, elderly, and patients with hepatic cirrhosis or heart failure. Smoking (tobacco or marijuana) reduces half-life to 1–2 hours due to enzyme induction. |
| Protein binding | Approximately 40% bound to albumin (primarily), with some binding to alpha-1-acid glycoprotein; binding is reduced in neonates and patients with hypoalbuminemia. |
| Volume of Distribution | 0.3–0.7 L/kg; approximates total body water. Higher Vd in neonates (0.8 L/kg) due to increased extracellular fluid. Clinically, loading dose calculation uses Vd = 0.5 L/kg. |
| Bioavailability | Oral immediate-release: 96–100% (virtually complete); sustained-release formulations: 80–100% (dependent on formulation and food effects). |
| Onset of Action | Oral immediate-release: 15–30 minutes; oral sustained-release: 1–2 hours; intravenous: 1–2 minutes. |
| Duration of Action | Immediate-release oral: 4–6 hours; sustained-release oral: 8–12 hours (based on dosing interval). Duration is dose-dependent and variable due to metabolism differences. |
| Molecular Weight | 180.17 |
Oral: 200-400 mg every 6 hours (maximum 1600 mg/day) as sustained-release tablets or liquid. Inhalation: Not applicable.
| Dosage form | ELIXIR |
| Renal impairment | No adjustment required for GFR >30 mL/min. For GFR 10-30 mL/min: reduce dose by 50% and increase interval to every 12 hours. For GFR <10 mL/min: give 200 mg every 12-24 hours. |
| Liver impairment | Child-Pugh A: no change. Child-Pugh B: reduce dose by 50% (maximum 800 mg/day). Child-Pugh C: reduce dose by 75% (maximum 400 mg/day) or increase interval to every 12-24 hours. |
| Pediatric use | Oral: Initial 5 mg/kg/dose every 6 hours; titrate to target serum concentration of 5-15 mcg/mL. Maximum: 20 mg/kg/day or 800 mg/day, whichever lower. |
| Geriatric use | Start at lowest adult dose (200 mg every 6 hours) and monitor serum levels; decreased clearance may necessitate lower maintenance doses. Maximum daily dose 800 mg. |
| 1st trimester | Theophylline has been associated with a small increased risk of congenital malformations in some studies, but data are conflicting. Use only if clearly needed. |
| 2nd trimester | No known increased risk during second trimester; monitor maternal serum levels due to physiologic changes in clearance. |
| 3rd trimester | Use near term may cause neonatal irritability, jitteriness, and tachycardia due to placental transfer. Monitor infant for toxicity. |
Clinical note
Comprehensive clinical and safety monograph for THEOLIXIR (THEOLIXIR).
| Placental transfer | Theophylline readily crosses the placenta with fetal serum concentrations approximating maternal levels. Peak levels in cord blood are similar to maternal serum. Clearance is decreased in preterm infants. |
| Breastfeeding | Theophylline is excreted into breast milk (~60-100% of maternal serum concentration). In maternal therapeutic doses, it may cause irritability or insomnia in nursing infants. Caution is advised; monitor infant for signs of caffeine-like stimulation. The AAP generally considers it compatible with breastfeeding, but use lowest effective dose and monitor infant serum levels if toxicity suspected. |
| Lactation Rating | L3 (Moderately Safe) - No controlled studies in breastfeeding women, but risk of adverse effects is possible. Weigh benefit vs risk. |
| Teratogenic Risk | Theophylline (active ingredient in THEOLIXIR) is not a major human teratogen. First trimester: Limited data show no consistent association with major malformations. Second/Third trimesters: Fetal tachycardia and jitteriness may occur at maternal therapeutic levels; toxicity can cause neonatal irritability, vomiting, and apnea. Risk of preterm labor or low birth weight not established. |
| Fetal Monitoring | Monitor maternal serum theophylline levels (therapeutic range 5-15 mcg/mL) to avoid toxicity. Assess fetal heart rate for tachycardia. Monitor neonatal for signs of theophylline toxicity (irritability, vomiting, jitteriness) if used near term. |
| Fertility Effects | No known adverse effects on fertility in humans. Animal studies show no impairment at clinically relevant doses. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to xanthine derivativesSeizure disorder not controlled by medication
| Precautions | Narrow therapeutic index; serum levels should be monitored to avoid toxicity, Risk of seizures, arrhythmias, and death at high concentrations, Caution in patients with hepatic impairment, congestive heart failure, pulmonary edema, or fever, Potential for drug interactions with CYP1A2 inhibitors/inducers |
| Food/Dietary | High-fat meals may alter theophylline absorption, leading to variable serum concentrations. Avoid excessive intake of caffeine-containing foods and beverages (e.g., coffee, tea, cola, chocolate) as they can potentiate stimulant effects and increase risk of toxicity. Charcoal-broiled foods may increase theophylline clearance, reducing efficacy. |
| Clinical Pearls | Theophylline (THEOLIXIR) has a narrow therapeutic index; serum levels should be maintained between 5-15 mcg/mL. Levels >20 mcg/mL increase toxicity risk. Administer with food if GI upset occurs, but avoid high-fat meals as they may increase absorption variability. Use with caution in patients with cardiac dysfunction, seizures, or peptic ulcer disease. Monitor for drug interactions with macrolides, fluoroquinolones, and cimetidine which decrease clearance. |
| Patient Advice | Take this medication exactly as prescribed; do not skip doses or double up. · Do not crush or chew extended-release tablets; swallow whole. · Get your blood levels checked regularly as directed by your doctor. · Avoid consuming large amounts of caffeine (coffee, tea, soda, chocolate) as it may increase side effects like jitteriness or rapid heartbeat. · Inform your doctor if you experience nausea, vomiting, restlessness, insomnia, or rapid heartbeat. · Do not stop taking this medicine suddenly without consulting your doctor. |
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