Comparison of side-effects of tetracycline and tetracycline plus nystatin. Report to the Research Committee of the British Tuberculosis Association by the Clinical Trials Subcommittee.

In a multicentre, double-blind, controlled trial of tetracycline plus nystatin (Mysteclin) and tetracycline, 111 patients with respiratory infections received one or other drug for a period of 10 days.The incidence of gastrointestinal symptoms was high in both groups before treatment began, and somewhat higher in the Mysteclin group than in the tetracycline group. After 10 days' treatment 50% of the patients in the Mysteclin group had symptoms, a mean of 1.44 each, compared with 34% of the patients in the tetracycline group, with a mean of 1.47 symptoms each; the difference between the two groups is not significant (P>0.05). The incidence of Candida albicans in the stools at 10 days in the Mysteclin group (9.1%) was significantly lower than that in the tetracycline group (37.1%), but this was not reflected in any reduction in the frequency of gastrointestinal symptoms.