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The Effects of Ephedrine and Theophylline on Dexamethasone Metabolism in Bronchial Asthma
Author(s) -
BROOKS STUART M.,
SHOLITON LEON J.,
WERK EMILE E.,
ALTENAU PAMELA
Publication year - 1977
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1002/j.1552-4604.1977.tb04610.x
Subject(s) - environmental medicine , medicine , family medicine , library science , gerontology , public health , nursing , computer science
The effect of ephedrine (nine patients) and theophylline (seven patients) on dexamethasone metabolism was studied before and after three weeks of drug therapy in 16 asthmatics. Five patients were studied similarily but treated with placebo. After treatment with ephedrine, there was a mean decrease in plasma dexamethasone half-life (t1/2) of 132 minutes, or 36 per cent (P less than 0.025), and mean increase in metabolic clearance rate (MCR) of 148 liters/day, or 42 per cent (P less than 0.001). Increase in the excretion of urinary radioactivity, predominantly in the conjugated fractions, was noted. In contrast, theophylline and placebo therapy resulted in no significant changes in dexamethasone t1/2 or MCR. The rate of urinary excretion of radioactivity was reduced after theophylline treatment. Since ephedrine accelerates labeled dexamethasone clearance while theophylline does not, caution is necessary when prescribing ephedrine for asthmatics requiring long-term therapy with dexamethasone and probably other corticosteroids. It would appear from the present investigation that theophylline is a more appropriate bronchodilator for these patients.