Treatment of gonorrhoea with a single oral dose of minocycline.

The gradual decrease in susceptibility of the gonococcus to penicillin has led authorities to recommend ever larger doses for the therapy of gonorrhoea. The current recommendation of the U.S. Public Health Service for the treatment of infections in women is the administration of 4-8 m.u. aqueous procaine penicillin; one half that amount is advised for cases in men. In seeking alternative antibiotics for the treatment of gonorrhoea, we have recently completed a trial of minocycline (7 dimethylamino-6-deoxy-6-dimethyltetracycine), a new semisynthetic derivative of tetracycline. The preparation and some biological properties of minocycline were described by Martell and Boothe (1967). Subsequent investigations (Fedorko, Katz, and Allnoch, 1968; Frisk and Tunevall, 1969; Washington, Yu, and Martin, 1970) have shown minocycline to have a broad spectrum much like tetracycline, with apparently more activity against the staphylococcus than tetracycline. Martin, Lester, Kellogg, and Thayer (1969) found that gonococcal strains isolated from patients after failure of treatment with penicillin were inhibited in vitro by minocycline at lower concentrations than was the case with tetracycline or doxycycline. The minimum inhibitory concentration (MIC) of minocycline ranged from 0125 to 1 0 ,Lg./ml. (mean 0 52); for tetracycline the MIC ranged from 0-125-20 ,±g./ml. (mean 075). Steigbigel, Reed, and Finland (1968a) tested 25 gonococcal strains in vitro and found minocycline to be more active than six other tetracyclines, 80 per cent. of the strains being inhibited by 0 4 jig./ml. or less. Steigbigel and others (1968b) also showed that single oral doses of 150 or 300 mg. minocycline gave higher and more prolonged serum levels than tetracycline. However, their subjects experienced significant nausea following the 300 mg. dose. Furthermore, their data show a mean serum level of minocycline