Toleration of intravenous azithromycin

OBJECTIVE: To study the toleration of various infusate concentrations of single intravenous doses of azithromycin. DESIGN: Randomized, double-blind, two-treatment, two-period, crossover. SETTING: Clinical pharmacology unit. PARTICIPANTS: Twenty-four healthy men aged 19-41 years. STUDY DESIGN: All subjects were initially randomized to receive single 1-hour intravenous infusions of azithromycin 1 g at infusate concentrations of 1, 2, or 5 mg/mL (n = 6 each) compared with placebo (n = 6). Subjects who were randomized to receive 1 mg/mL concentrations were subsequently administered 5 mg/mL concentrations at least 2 weeks later, those given 2 mg/mL were crossed over to 4 mg/mL, and those in the 5-mg/mL group were crossed over to 1 mg/mL concentrations. MAIN OUTCOME MEASURES: Subjects recorded intravenous infusion toleration using visual analog scales ranging from 0 (no signs or symptoms) to 10 (poor toleration) for erythema, pain, swelling, and tenderness. Vascular Doppler recordings were obtained during and after infusion cephalad to the infusion site. RESULTS: Infusion site reactions increased in incidence and severity with infusion concentrations of 4 and 5 mg/mL; the most frequent reactions were tenderness and erythema. There were no apparent trends in Doppler readings. CONCLUSIONS: Single doses of azithromycin 1 g at infusate concentrations up to 2 mg/mL were well tolerated when administered over 1 hour to healthy men.