Uses
As a synthetic beta-lactamase-resistant penicillin, Nafcillin SodiuM Salt can be used to treat infections caused by Gram-positive bacteria, in particular, species of staphylococci that are resistant to other penicillins.
Uses
Nafcillin SodiuM Salt can be used as narcotic antagonist
Brand name
Nallpen (GlaxoSmithKline).
Antimicrobial activity
The antibacterial spectrum is similar to that of the isoxazolylpenicillins but it is more active against streptococci and pneumococci. Activity in vitro is depressed in the presence of serum. It is more stable than the isoxazolylpenicillins to staphylococcal β-lactamase. There is complete cross-resistance with other group 3 penicillins.
Pharmacokinetics
Oral absorption: c. 35%
Cmax 1 g intramuscular:8 mg/L after 1 h
500 mg intravenous:30 mg/L after 5 min
Plasma half-life: 0.5 h
Plasma protein binding: 90%
Absorption and distribution
Nafcillin is poorly absorbed after oral administration, and absorption is further depressed if the drug is given with food. Most dosing is now intravenous. Penetration into tissues is similar to that of the isoxazolylpenicillins. Penetration into normal meninges is low, but is higher in inflamed meninges.
Metabolism and excretion
About 60–70% is inactivated in the liver. Following intramuscular administration, about 30% appears in the urine, producing concentrations up to 1000 mg/L. Administration of probenecid reduces the urinary excretion and raises and prolongs the plasma level. About 8% of the dose is excreted in the bile.
Clinical Use
Uses are those of group 3 penicillins . Nafcillin has been particularly recommended for the treatment of staphylococcal bacteremia caused by susceptible strains.
Side effects
There is cross-allergenicity with other penicillins. Its side effects are similar to the penicillins. Pseudomembranous colitis has been reported.
China
