Pharmacokinetic study of azithromycin with fluconazole and cotrimoxazole (trimethoprim-sulfamethoxazole) in healthy volunteers.

BACKGROUND

Azithromycin, fluconazole and cotrimoxazole (trimethoprim-sulfamethoxazole; TMP/SMX) are all agents that are utilised for the treatment and/or prophylaxis of opportunistic infections in patients with AIDS.

OBJECTIVE

To characterise the potential for an interaction when azithromycin is coadministered with cotrimoxazole or with fluconazole.

DESIGN

Two separate nonblind randomised studies were conducted in healthy volunteers. During the fluconazole study the potential for fluconazole to adversely affect the pharmacokinetics of azithromycin was also studied.

PARTICIPANTS

24 (cotrimoxazole) and 18 (fluconazole) healthy male and female volunteers.

RESULTS

The results of both studies indicated that neither the peak concentrations of nor the exposures (area under the concentration-time curve) to the test drugs were changed when azithromycin was coadministered. In addition, fluconazole did not significantly alter the pharmacokinetic parameters of azithromycin.

CONCLUSIONS

Azithromycin does not alter the bioavailability of either cotrimoxazole or fluconazole.