THEOBID
Clinical safety rating
cautionComprehensive clinical and safety monograph for THEOBID (THEOBID).
Theophylline is a methylxanthine that relaxes bronchial smooth muscle by inhibiting phosphodiesterase, increasing cAMP, and blocking adenosine receptors. It also has anti-inflammatory and immunomodulatory effects.
| Metabolism | Primarily hepatic via CYP1A2, with minor contributions from CYP2E1 and CYP3A4. Exhibits saturable (nonlinear) pharmacokinetics at high doses. |
| Excretion | Renal (10% unchanged), hepatic metabolism (90%, primarily via CYP1A2 and CYP3A4); 20% excreted in feces as metabolites. |
| Half-life | Neonates: 24-36 h; Children (1-9 y): 3-4 h; Adults (non-smokers): 6-12 h; Adults (smokers): 4-5 h; Hepatic cirrhosis: prolonged (up to 30 h); Heart failure: prolonged (up to 20 h). |
| Protein binding | 40-60% (primarily to albumin). Decreased binding in neonates, hepatic disease, and uremia. |
| Volume of Distribution | 0.45 L/kg (range: 0.3-0.7 L/kg). Higher in neonates (0.7-0.9 L/kg). Represents distribution throughout total body water. |
| Bioavailability | Oral: 96-100% (immediate release); Sustained release (THEOBID): ~100% (bioequivalent to immediate release at steady state); IV: 100%; Rectal: ~80-100%. |
| Onset of Action | Oral (immediate release): 15-30 min; Oral (sustained release, e.g., THEOBID): 1-2 h; IV: immediately; Rectal: 15-30 min. |
| Duration of Action | Oral (sustained release): 8-12 h (dose-dependent). Clinical note: Therapeutic serum levels (10-20 mcg/mL) maintained with twice-daily dosing. |
| Molecular Weight | 180.16 |
| Action Class | Theophylline & its derivatives |
| Brand Substitutes | Theo PA 300mg Tablet, Phylobid 300mg Tablet, Onimar 300mg Tablet, Uniresp 300mg Tablet, OD PHYLLIN 600 MG TABLET, Theoday 600mg Tablet, Theoresp 600mg Tablet, Theoresp Plus 600mg Tablet |
Theophylline extended-release capsules: 300-600 mg/day orally divided every 12 hours. Initial dose 300 mg/day, titrate based on serum concentrations (target 10-20 mcg/mL). Max 600 mg/day unless serum levels monitored.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | No specific GFR-based dose adjustment for theophylline. However, accumulation may occur in severe renal impairment; monitor serum levels and adjust dose to achieve therapeutic concentrations (10-20 mcg/mL). |
| Liver impairment | Child-Pugh Class A: Reduce dose by 50%. Child-Pugh Class B or C: Reduce dose by 75% or use alternative. Monitor serum concentrations closely. |
| Pediatric use | For asthma: Oral immediate-release: 5 mg/kg/day divided q6-8h. Extended-release: 10-20 mg/kg/day divided q12h (max 600 mg/day). Target serum concentration 5-15 mcg/mL. Dosing based on age and weight, titrate slowly. |
| Geriatric use | Elderly patients (>60 years) often have reduced clearance. Start with 300 mg/day orally extended-release, titrate slowly to lowest effective dose. Monitor serum concentrations closely to avoid toxicity (target 5-15 mcg/mL). |
| 1st trimester | Risk not ruled out. May be used if benefits outweigh risks. Limited human data; no evidence of teratogenicity in animal studies. |
| 2nd trimester | Risk not ruled out. May be used if benefits outweigh risks. Monitor for maternal and fetal effects (tachycardia, jitteriness). |
| 3rd trimester | Risk not ruled out. May be used if benefits outweigh risks. Monitor neonatal for irritability, tachycardia, and jitteriness. |
Clinical note
Comprehensive clinical and safety monograph for THEOBID (THEOBID).
| Placental transfer | Crosses placenta extensively; umbilical cord blood concentrations are similar to maternal serum concentrations. |
| Breastfeeding | Theophylline is excreted into breast milk in small amounts. Infant exposure is typically low (estimated 1-10% of maternal weight-adjusted dose). However, infants may experience irritability and insomnia. Premature or ill infants may be more sensitive. Consider monitoring infant for adverse effects. |
| Lactation Rating | L3 (Moderately safe) |
| Teratogenic Risk | Theophylline (THEOBID) is not considered a major teratogen. First trimester: Limited data show no significant increase in congenital malformations. Second and third trimesters: No known structural effects; fetal tachycardia and irritability may occur due to maternal toxicity. Neonatal withdrawal (jitteriness, vomiting) reported with third-trimester use. |
| Fetal Monitoring | Maternal: Serum theophylline levels (target 5-15 mcg/mL), heart rate, CNS stimulation, nausea/vomiting, and signs of toxicity (seizures, arrhythmias). Fetal: Heart rate monitoring for tachycardia (may indicate maternal toxicity). Neonatal: Observe for jitteriness, irritability, vomiting, and apnea (especially in preterm infants). |
| Fertility Effects | No known adverse effects on human fertility. Animal studies have not shown impaired fertility at therapeutic doses. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
Hypersensitivity to theophylline or any component of the formulationActive peptic ulcer diseaseSeizure disorder (unless adequately controlled with anticonvulsants)
| Precautions | Risk of serious cardiovascular toxicity (arrhythmias, seizures, death) especially at serum levels >20 mcg/mL, Cautious use in patients with peptic ulcer, seizure disorders, cardiac disease, hepatic impairment, Monitor serum theophylline levels to avoid toxicity, Reduce dose in smokers and with drugs that induce CYP1A2 (e.g., phenytoin, rifampin), Avoid in patients with active peptic ulcer or uncontrolled seizure disorders |
| Food/Dietary | High-fat meals can increase absorption of sustained-release formulations. Charcoal-broiled foods and a high-protein, low-carbohydrate diet can increase theophylline clearance. Avoid concurrent ingestion of caffeine-containing foods/beverages. |
| Clinical Pearls | Theophylline levels must be monitored; narrow therapeutic index (5-15 mcg/mL). Avoid in patients with active peptic ulcer disease or seizure disorders. Use with caution in heart failure, hepatic impairment, and elderly. Many drug interactions (e.g., cimetidine, fluoroquinolones, macrolides) increase levels. Smoking induces metabolism, requiring higher doses. |
| Patient Advice | Take exactly as prescribed; do not change dose without consulting doctor. · Do not crush or chew sustained-release capsules. · Avoid excessive caffeine (coffee, tea, cola, chocolate) as it may increase side effects. · Report symptoms like nausea, vomiting, palpitations, insomnia, or seizures. · Notify doctor if you start or stop smoking, or if you are prescribed new medications. · Keep regular appointments for blood level monitoring. |
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