Theophylline Pharmacokinetics After Intramuscular Administration

Abstract

This study was aimed at assessing the pharmacokinetics of a single dose of theophylline solution (aminophylline 480 mg) administered by intramuscular (j.m.) route to 16 subjects (age 28-61 years, body weight 52-75 kg). The same dose was given a week apart by oral route in fasting conditions. The intraindividual comparison shows that by i.m. route the rate, but not the extent, of absorption may be somewhat lower. From the first hour on, until hour 3-4 after i.m. dosing, all subjects achieved a safe and effective serum theophylline concentration (9-17 mg/liter). This suggests that, although usually not recommended, self-administration of a single dose of aminophylline by i.m. route may temporarily help theophylline-responsive patients in distress, when other routes of administration are not available and facilities for intensive conventional treatment are lacking.