[The theophylline test. Indications for the effective daily dosage (author's transl)]

The great variability in the metabolism and degradation of theophylline in different people demands an individual dosage to be effective; this is to maintain the theophylline levels between the threshold of therapeutic activity (10 mg/L) to the upper limit of tolerance (15 to 20 mg/L according to different studies). The effective individual doses may be determined before commencing treatment by a Theophylline Test. This allows the dose over 24 hours to be specified as well as the number of tablets necessary to maintain the theophylline levels in the chosen range. The principle of the Theophylline Test is to administer intravenously a test dose of theophylline, then with 5 successive samples for blood theophylline to assess the individual elimination of the drug. For each subject two pharmacokinetic parameters are determined: clearance and plasma half life. The plasma clearance allows the total dose over 24 hours to be calculated, the half life the number of doses and the type of preparation used: microkrystalline theophylline (Techniphylline), slow release theophylline (Theophylline Bruneau) and prolonged action theophylline (Armophylline).