THEOBID JR.
Clinical safety rating: caution
Comprehensive clinical and safety monograph for THEOBID JR. (THEOBID JR.).
Inhibits phosphodiesterase, increasing intracellular cAMP; causes bronchodilation, central nervous system stimulation, and positive inotropic/chronotropic effects.
| Metabolism | Hepatic via CYP1A2, CYP2E1, and CYP3A4; exhibits nonlinear pharmacokinetics at high concentrations. |
| Excretion | Hepatic metabolism (90%), renal excretion of unchanged drug (10%). Metabolites excreted in urine. |
| Half-life | 3-8 hours in adults; prolonged in neonates, cirrhosis, heart failure (up to 30 hours). Tobacco smoking induces clearance (half-life 4-5 hours). |
| Protein binding | Approximately 55-65%, primarily to albumin. |
| Volume of Distribution | 0.3-0.7 L/kg; approximates total body water. |
| Bioavailability | Oral: 100% (well absorbed). Food may affect absorption rate but not extent. |
| Onset of Action | Oral: 30-60 minutes (peak bronchodilation within 2-3 hours). |
| Duration of Action | Extended-release formulation: 12-24 hours. Therapeutic serum levels (10-20 mcg/mL) maintained with twice-daily dosing. |
300 mg orally every 12 hours, extended-release tablet. Titrate to serum theophylline concentration of 5-15 mcg/mL.
| Dosage form | CAPSULE, EXTENDED RELEASE |
| Renal impairment | No adjustment required for GFR > 50 mL/min. For GFR 10-50 mL/min: administer 75% of normal dose every 12 hours. For GFR < 10 mL/min: administer 50% of normal dose every 12 hours. Monitor serum levels. |
| Liver impairment | Child-Pugh A: reduce dose by 50%. Child-Pugh B: reduce dose by 60%. Child-Pugh C: reduce dose by 75% or use alternative therapy. Monitor serum levels closely. |
| Pediatric use | 1-9 years: 24 mg/kg/day divided every 12 hours. 9-12 years: 20 mg/kg/day divided every 12 hours. 12-16 years: 18 mg/kg/day divided every 12 hours. Titrate to serum concentration of 5-15 mcg/mL. |
| Geriatric use | Initiate at 200 mg orally every 12 hours. Reduce target serum concentration to 5-10 mcg/mL. Monitor for increased half-life and toxicity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for THEOBID JR. (THEOBID JR.).
| Breastfeeding | Theophylline is excreted into human breast milk with an M/P ratio of approximately 0.7. Levels are generally low, but can cause irritability or insomnia in infants. Caution is advised, especially with high maternal doses. |
| Teratogenic Risk | Theophylline (active ingredient in THEOBID JR.) is not considered a major human teratogen. First trimester: Limited data suggest no significant increase in major malformations. Second and third trimesters: No known teratogenic effects, but high doses may be associated with fetal tachycardia and jitteriness. Use only if clearly needed. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to theophylline or any component.","Pre-existing arrhythmias (relative).","Active seizure disorder (relative)."]
| Precautions | ["Narrow therapeutic index; monitor serum levels (therapeutic range 10-20 mcg/mL).","Risk of toxicity with interactions (e.g., cimetidine, fluoroquinolones, macrolides).","Seizures and arrhythmias may occur at high concentrations.","Use caution in patients with heart failure, liver disease, or fever."] |
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| Fetal Monitoring | Monitor maternal serum theophylline levels (target 5-15 mcg/mL), heart rate, and signs of toxicity. Fetal monitoring for heart rate abnormalities, especially if maternal levels are high. |
| Fertility Effects | No well-documented adverse effects on fertility in humans. Animal studies have not shown significant reproductive toxicity. |