Pivampicillin

Pivampicillin is a pivaloyloxymethyl ester of ampicillin. It is a prodrug, which is thought to enhance the oral bioavailability of ampicillin because of its greater lipophilicity compared to that of ampicillin.

Adverse effects
Prodrugs that release pivalic acid when broken down by the body—such as pivampicillin, pivmecillinam and cefditoren pivoxil—have long been known to deplete levels of carnitine. This is not due to the drug itself, but to pivalate, which is mostly removed from the body by forming a conjugate with carnitine. Although short-term use of these drugs can cause a marked decrease in blood levels of carnitine, it is unlikely to be of clinical significance; long-term use, however, appears problematic and is not recommended.