[Investigation on optimal regimen of ceftazidime against infection caused by Pseudomonas aeruginosa using Monte Carlo simulation].

An optimal regimen for the use of ceftazidime (CAZ) (one of injectable antimicrobial agents in cephem family) against Pseudomonas aeruginosa infection was explored, using Monte Carlo simulation. Pharmacokinetic parameters needed for Monte Carlo simulation were derived from the existing data for healthy adults, and the data on MIC distribution of CAZ against clinically isolated bacterial strains reported by Working Group of Forum on Microbial Resistance. When CAZ was used within the currently approved dosage and administration for adults (4 g/day at maximum), intravenous administration of CAZ, 1 g, t.i.d., per day was found to have the highest probability to achieve the target of maximum bactericidal activity for cephems, i.e., 60-70%T > MIC (time above MIC). The probability to achieve the same target was the second highest with two intravenous CAZ, 2 g, b.i.d., per day, and third with CAZ, 1 g, b.i.d., per day. These results suggest that when treating P. aeruginosa infection with CAZ, for which T > MIC serves as PK/PD parameter, increasing the frequency of dosing is effective method to reinforce its efficacy, and that CAZ, t.i.d., per day is an optimal dosage and administration within the range of the regimens described in its package insert.