Azithromycin and terfenadine: lack of drug interaction.
A double-blind placebo-controlled study was conducted in healthy men to determine the effect of coadministration of azithromycin on the pharmacodynamics and pharmacokinetics of terfenadine. Administration of 500 mg azithromycin for 1 day and 250 mg on 4 subsequent days did not affect the pharmacokinetics of the pharmacologically active terfenadine carboxylate metabolite when 60 mg terfenadine was given twice daily for 12 days, starting 7 days before azithromycin administration. Terfenadine alone resulted in a 0.010 msec increase in the rate-corrected QT interval (QTc), but the incremental effects of azithromycin and placebo on QTc in volunteers receiving terfenadine were not statistically different. It is concluded that the potentially life-threatening disorders that have been attributed to a pharmacokinetic interaction between macrolide antibiotics and terfenadine are unlikely to take place in patients treated simultaneously with azithromycin and terfenadine.
Harris
S
S
South Florida Bioavailability Clinic Inc., Miami, Fla., USA.
Hilligoss
D M
DM
Colangelo
P M
PM
Eller
M
M
Okerholm
R
R
D000328:Adult; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology*; D017963:Azithromycin / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology*; D004311:Double-Blind Method; D004347:Drug Interactions; D004562:Electrocardiography / Q000187:drug effects; D006634:Histamine H1 Antagonists / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology*; D006801:Humans; D008297:Male; D010919:Placebos; D016593:Terfenadine / Q000009:adverse effects / Q000493:pharmacokinetics / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D006634:Histamine H1 Antagonists; D010919:Placebos; D016593:Terfenadine; D017963:Azithromycin