LANOPHYLLIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LANOPHYLLIN (LANOPHYLLIN).
Lanophyllin is a xanthine derivative that inhibits phosphodiesterase, leading to increased intracellular cyclic AMP levels. It also antagonizes adenosine receptors, resulting in bronchodilation, respiratory stimulation, and anti-inflammatory effects.
| Metabolism | Primarily hepatic via CYP1A2, with minor contributions from CYP2E1 and CYP3A4. Metabolites include 3-methylxanthine, 1-methyluric acid, and 1,3-dimethyluric acid. |
| Excretion | Renal excretion of unchanged drug accounts for approximately 10% of elimination; hepatic metabolism accounts for 90%, with metabolites excreted in urine. Biliary/fecal excretion is negligible (<2%). |
| Half-life | Terminal elimination half-life is 7-9 hours in healthy adults; increases to 20-30 hours in congestive heart failure, cirrhosis, or severe COPD; decreases to 3-5 hours in smokers (tobacco or marijuana) due to enzyme induction. |
| Protein binding | Approximately 40% bound to albumin; binding is nonlinear and decreases at higher serum concentrations. |
| Volume of Distribution | 0.4-0.7 L/kg, approximating total body water (0.45 L/kg in adults). Vd is increased in neonates (0.6 L/kg) and decreased in obesity (0.3-0.4 L/kg) due to reduced lean body mass. |
| Bioavailability | Oral immediate-release: 90-100%; Oral sustained-release: 80-100% relative to immediate-release; Rectal solution: 100%; Rectal suppository: 60-80% (erratic). |
| Onset of Action | Oral (immediate-release): 30-60 minutes; Oral (sustained-release): 1-2 hours; Intravenous: 5-10 minutes; Rectal (solution): 30-60 minutes. |
| Duration of Action | Oral (immediate-release): 6-8 hours; Oral (sustained-release): 12-24 hours depending on formulation; Intravenous: 4-6 hours; Rectal (solution): 6-8 hours. Duration is primarily limited by redistribution and metabolism. |
5-6 mg/kg IV loading dose over 20-30 minutes, then 0.4-0.6 mg/kg/hour continuous IV infusion; maintenance oral dose 300-600 mg/day in divided doses every 8-12 hours.
| Dosage form | ELIXIR |
| Renal impairment | For GFR <30 mL/min: reduce maintenance dose by 50%; consider monitoring serum concentrations. |
| Liver impairment | Child-Pugh Class A: reduce dose by 50%; Child-Pugh Class B: reduce dose by 75%; Child-Pugh Class C: avoid use or use with extreme caution with 80% dose reduction. |
| Pediatric use | IV loading dose: 5-7 mg/kg over 20-30 minutes; maintenance IV infusion: 0.5-1 mg/kg/hour for ages 1-9 years, 0.4-0.7 mg/kg/hour for ages 9-16 years; oral: 10-20 mg/kg/day in divided doses every 6-8 hours, maximum 600 mg/day. |
| Geriatric use | Elderly patients: reduce loading dose to 4-5 mg/kg; maintenance dose 0.2-0.3 mg/kg/hour IV or 200-400 mg/day oral; monitor serum theophylline levels closely due to decreased clearance. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LANOPHYLLIN (LANOPHYLLIN).
| Breastfeeding | Excreted into breast milk; M/P ratio approximately 0.6-0.8. Relative infant dose is low (<10% of maternal weight-adjusted dose). No reports of adverse effects in breastfed infants. Caution advised in preterm or ill infants. |
| Teratogenic Risk | Insufficient human data; animal studies show no evidence of teratogenicity at clinically relevant doses. First trimester: no known increase in major malformations. Second and third trimesters: no known adverse fetal effects. However, use only if clearly needed. |
■ FDA Black Box Warning
None explicitly required by FDA, but use with caution due to narrow therapeutic index and potential for severe toxicity.
| Serious Effects |
Hypersensitivity to xanthines, active seizure disorders, severe arrhythmias, and uncontrolled hyperthyroidism.
| Precautions | Narrow therapeutic index; monitor serum concentrations regularly. Risk of arrhythmias, seizures, and gastrointestinal bleeding. Use lower doses in heart failure, liver disease, and elderly. Avoid abrupt discontinuation due to withdrawal symptoms. |
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| Fetal Monitoring |
| Monitor maternal serum drug levels (therapeutic range 5-15 mcg/mL), especially in late pregnancy due to reduced clearance. Monitor fetal heart rate and growth if used near term. Assess for maternal signs of toxicity (nausea, vomiting, tachycardia, arrhythmias, seizures). |
| Fertility Effects | No significant effects on human fertility reported. Animal studies show no impairment of fertility at therapeutic doses. |