Effects of minocycline and tetracycline on the vaginal yeast flora

Two groups of women with non-specific genital infection were treated for two weeks with tetracycline 250 mg six-hourly and minocycline 100 mg twice daily respectively. Cultures for yeasts were performed before treatment and at the end of the first and second weeks. Before treatment yeasts, mostly Candida albicans, were recovered from 13% of the women. After one and two weeks' treatment yeasts were isolated from 22 and 29% of women treated with tetracycline, and from 19 and 29% of women treated with minocycline. It is concluded that despite inhibition of the growth of yeasts shown by minocycline in vitro, there is no evidence of any significant difference between the actions of tetracycline and minocycline on the vaginal yeast flora.