Microbiology, pharmacology, and clinical use of mezlocillin sodium.

The acylureido penicillin mezlocillin is active against gram-positive, gram-negative, and anaerobic bacteria. It easily penetrates the outer membrane of gram-negative bacteria, and it has a strong affinity for penicillin binding protein 3. Its stability to beta-lactamases is weak. Mezlocillin is synergistic when given in combination with aminoglycoside antibiotics. In pharmacokinetic studies mezlocillin conforms to a two compartment open model; its pharmacokinetic properties are dose-dependent. The half-life of the drug is about 1 hour after intravenous injection and 1.5 hours after intramuscular injection. Protein binding ranges from 16 to 42%, and 55% of a dose is excreted in the urine. Biliary excretion ranges from 0.5 to 25%. Clinical trial cure rates were as follows: bacteremia (78%), respiratory tract (62%), urinary tract (81%), gynecological (86%), bone and joint (55%), intraabdominal (67%) and skin and soft tissue (59%). The frequency of adverse reactions was 7.7%. Interstitial nephritis, CNS toxicity, and bleeding have not been reported.