1977 Volume 25 Issue 1 Pages 163-172
1. In vitro antibacterial activities of mecillinam varied with inoculum size. Its antibacterial activities with 106 cells/ml inoculum size were more potent than with 108 cells/ml. Staphylococcus aureus and Serratia marcescens were less susceptible to mecillinam than to ampicillin with 106 cells/ml. E. coli showed, with 108 cells/ml, slightly higher susceptibility to mecillinam than to ampicillin and, with 106 cells/ml, exceedingly higher susceptibility to mecillinam than to ampicillin. Klebsiella showed, with 106 cells/ml, considerably higher susceptibility to mecillinam than to ampicillin, but was less susceptible with 108 cells/ml to mecillinam as well as to ampicillin.
2. Peak serum mecillinam level appeared one hour after oral administration of pivmecillinam. The peak level was 0.78 μg/ml following a 50mg dose, 1.71 μg/ml following a 100mg dose and 2.95 μg/ml following a 200 mg dose. Six-hour urinary recovery was 56.8% after a 50 mgdose, 51.5% after a 100mg dose and 51.7% after a 200mg dose. Bile mecillinam concentration increased with time until 3 hours after administration but was lower than the serum level.
3. Three cases with biliary infections and 9 cases with urinary-tract infections were given pivmecillinam. Of 3 cases suffered from cholecystitis with gallstone, the response was clinically good in 2 cases and bacte-riologically good in 1 case. Of 2 cases with acute pyelonephritis and 3 with acute cystitis, 4 cases responded to the therapy clinically and bacteriologically. Of 4 cases with chronic cystitis with indwelling catheter, the response was clinically good in 2 cases and bacteriologically good in 1.
4. No note worthy side effects were observed except gastric disterbances noted in 2 cases who were given doses of 600 and 800 mg per day. Chemical analysis of blood demonstrated no abnomal findings.
