Ampicillin sulbactam clinical pharmacology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Clinical Pharmacology
Immediately after completion of a 15-minute intravenous infusion, peak serum concentrations of ampicillin and sulbactam are attained. Ampicillin serum levels are similar to those produced by the administration of equivalent amounts of ampicillin alone. Peak ampicillin serum levels ranging from 109 to 150 mcg/mL are attained after administration of 2000 mg of ampicillin plus 1000 mg sulbactam and 40 to 71 mcg/mL after administration of 1000 mg ampicillin plus 500 mg sulbactam. The corresponding mean peak serum levels for sulbactam range from 48 to 88 mcg/mL and 21 to 40 mcg/mL, respectively. After an intramuscular injection of 1000 mg ampicillin plus 500 mg sulbactam, peak ampicillin serum levels ranging from 8 to 37 mcg/mL and peak sulbactam serum levels ranging from 6 to 24 mcg/mL are attained. The mean serum half-life of both drugs is approximately 1 hour in healthy volunteers. Approximately 75 to 85% of both ampicillin and sulbactam are excreted unchanged in the urine during the first 8 hours after administration to individuals with normal renal function. Somewhat higher and more prolonged serum levels of ampicillin and sulbactam can be achieved with the concurrent administration of probenecid.
In patients with impaired renal function the elimination kinetics of ampicillin and sulbactam are similarly affected, hence the ratio of one to the other will remain constant whatever the renal function. The dose in such patients should be administered less frequently in accordance with the usual practice for ampicillin. Ampicillin has been found to be approximately 28% reversibly bound to human serum protein and sulbactam approximately 38% reversibly bound.
Penetration of both ampicillin and sulbactam into cerebrospinal fluid in the presence of inflamed meninges has been demonstrated after IV administration of ampicillin/sulbactam. The pharmacokinetics of ampicillin and sulbactam in pediatric patients receiving ampicillin/sulbactam are similar to those observed in adults. Immediately after a 15-minute infusion of 50 to 75 mg ampicillin/sulbactam per kg body weight, peak serum and plasma concentrations of 82 to 446 mcg ampicillin/mL and 44 to 203 mcg sulbactam/mL were obtained. Mean half-life values were approximately 1 hour.[1]
| Fluid or Tissue | Dose (grams) | Concentration (mcg/mL or mcg/g) |
| Peritoneal Fluid | 0.5/0.5 IV | 7/14 |
| Blister Fluid (Cantharides) | 0.5/0.5 IV | 8/20 |
| Tissue Fluid | 1/0.5 IV | 8/4 |
| Intestinal Mucosa | 0.5/0.5 IV | 11/18 |
| Appendix | 2/1 IV | 3/40 |
References
- ↑ "http://www.accessdata.fda.gov/drugsatfda_docs/label/2012/050608s040lbl.pdf" (PDF). External link in
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Adapted from the FDA Package Insert.