A randomized double-blind trial of 152 men with gonococcal urethritis compared the therapeutic efficacy of erythromycin estolate and erythromycin base. Twenty-one of 86 (24%) men treated with the estolate and 15 of 66 (23%) treated with the base had recurrent or persistent gonococcal infection when seen after a 9-g course of erythromycin. The serum erythromycin activity among estolate-treated patients (3.57±0.84 μg/ml) was nearly twice that for base-treated patients (1.76±0.80 μg/ml). Our findings do not support routine use of erythromycin for treatment of pregnant, penicillin-allergic patients.
(JAMA 238:1371-1373, 1977)
Brown ST, Pedersen AHB, Holmes KK. Comparison of Erythromycin Base and Estolate in Gonococcal Urethritis. JAMA. 1977;238(13):1371–1373. doi:10.1001/jama.1977.03280140049015