ABSTRACT
Several antibiotics have been reported to lessen the ovarian suppression produced by oral contraceptive agents, as a result of drug interactions. The present investigation was designed to study the likelihood of the occurrence of any such interaction between the fluoroquinolone antibiotic ciprofloxacin (Ciproxin) at a dosage of 500 mg twice a day and the "low-dose" oral contraceptive Marvelon (30 microgram of ethinyl estradiol [EE] plus 150 microgram of desogestrel). Twenty-four healthy female volunteers were studied in a double-blind, placebo-controlled, randomized crossover trial. There were no significant differences between measurements of the area under the concentration-time curve of EE up to 24 h after oral contraceptive intake during placebo and ciprofloxacin administration on days 11 and 16 of the cycles, indicating the absence of pharmacokinetic interaction. Similarly, no clinically significant differences in the levels of sex hormone binding globulin were found between the placebo and ciprofloxacin cycles, indicating no major variation in EE levels during ciprofloxacin and placebo treatment. Ten subjects in each of the placebo and ciprofloxacin groups had early-follicular-phase levels of 17-beta estradiol (<184 ng/liter) at one or more points during their cycles, but none had values above the early-follicular-phase range, indicating no significant ovarian activity. In addition, all subjects had progesterone levels of <2 ng/ml, indicating the absence of ovulation. Only two subjects, who received the placebo, had evidence of sustained follicular growth to a potentially ovulatory follicle ( approximately 18 mm). We conclude that ciprofloxacin does not interfere with the ovarian suppression produced by the low-dose oral contraceptive Marvelon.
PIP: A single-center, double-blind, placebo-controlled randomized crossover trial involving 24 healthy female volunteers, aged 19-32 years, was undertaken to assess whether ciprofloxacin (Ciproxin) affects the contraceptive effect of Marvelon (30 mcg of ethinyl estradiol [EE] plus 150 mcg of desogestrel). The study also evaluated the follicle ripening in ovaries by measuring the increase in mean follicular diameter in the subovulatory cycles during treatment with ciprofloxacin. The volunteers were divided into 2 blocks of 12 individuals, randomly allocated to 1 of 2 treatment order groups, with 6 individuals per group. One group received Marvelon, 1 tablet daily on days 8-28 of each cycle, and Ciprofloxacin or the placebo group administered twice daily on days 8-17 of cycles. Findings revealed that there were no significant differences between measurements of the area under the concentration-time curve of EE up to 24 hours after oral contraceptive intake during placebo and ciprofloxacin administration on days 11 and 16 of the cycles, indicating the absence of pharmacokinetic interaction. Similarly, no clinically significant differences in the levels of sex hormone binding globulin were found between the placebo and ciprofloxacin cycles, indicating no major variation in EE levels during ciprofloxacin and placebo treatment. In conclusion, ciprofloxacin does not appear to alter ovarian activity when co-administered with the low-dose oral contraceptive Marvelon. No evidence of pharmacokinetic interaction between the antibiotic and the contraceptive was detected.
