[Prevention of postoperative anaerobic infections. Economic significance of metronidazole suppositories].

Metronidazole is widely used in the preventive and curative treatment of post-operative anaerobic infections. As the intravenous form is very expensive, a 1 g suppository has been developed. The pharmacokinetics of metronidazole injection and suppository was studied comparatively in 10 healthy subjects. The serum bioavailability of the rectal form was 80% with a peak serum concentration of 10 mg/l four hours after dosing. From calculated pharmacokinetic values it may be suggested that: (1) in cases of elective surgery treatment could begin with the rectal form alone at the rate of one suppository 12-hourly, starting 48 hours before surgery; (2) in emergency surgery, 0,5g of metronidazole i.v. over 20 minutes and a 1 g suppository should be administered at the time of premedication, treatment being continued with one suppository 12-hourly; (3) in patients at high risk of anaerobic infection, one suppository should be given 8-hourly, starting 24 hours before surgery. The main advantage of the rectal treatment is that it is much cheaper than the intravenous treatment administered during the same period.