The clinical efficacies of
pivmecillinam and
ampicillin were compared in a randomized double-blind trial in the treatment of acute
shigellosis. Of 44 adult male patients, all culture positive for Shigella strains, 22 patients received 400 mg of
pivmecillinam and 22 patients received 500 mg of
ampicillin every 6 h. Both drugs were administered orally for 5 days. Four patients receiving
ampicillin were infected with Shigella strains that were resistant to
ampicillin but susceptible to
pivmecillinam, and two patients receiving
pivmecillinam were infected with Shigella strains resistant to both
ampicillin and
pivmecillinam. The mean duration of
diarrhea in all patients receiving
pivmecillinam was 3.3 days compared with 4.5 days in patients receiving
ampicillin (P less than 0.05). When patients infected with the resistant strains were excluded, the mean duration of
diarrhea in patients receiving
pivmecillinam was 3.2 days compared with 4.1 days in patients receiving
ampicillin. The patients infected with strains susceptible to both
antibiotics had mean durations of fecal excretion of Shigella strains of 1.2 days for those treated with
pivmecillinam and 1.4 days for those treated with
ampicillin. The patients infected with organisms resistant to both drugs had longer durations of
diarrhea and fecal excretion of Shigella strains. The results suggest that
pivmecillinam is as effective as
ampicillin and can be a useful
drug for the treatment of
shigellosis.