to other penicillins: allopurinol increases the risk for patients to develop rashes. Penicillins slow down the elimination of methotrexate, potentially increasing its adverse effects. Conversely, the elimination of sultamicillin's active constituents (ampicillin and sulbactam) is reduced by probenecid and probably by the nonsteroidal anti-inflammatory drugs (NSAIDs) aspirin, indometacin and phenylbutazone. Pharmacology Pharmacokinetics Sultamicillin is a codrug or (mutual prodrug) of ampicillin and sulbactam. After oral intake, it is absorbed and hydrolytically cleaved to ampicillin and sulbactam by enzymes in the gut wall. These two substances are then released into the system in a 1:1 molar ratio. Their pharmacokinetic behaviour is similar (and practically independent of food intake): they reach peak concentrations after about one hour; their plasma protein binding is 26% (ampicillin) and 29% (sulbactam); and their elimination half-lives are 45–80 minutes and 40–70 minutes, respectively. Both drugs are mainly eliminated via the kidneys: within eight hours after intake, 46 to 80% of the ampicillin and 41 to 66% of the sulbactam are found in the urine. Mechanism of action Ampicillin, a semi-synthetic orally active broad-spectrum penicillin antibiotic, exerts antibacterial activity against sensitive organisms by inhibiting biosynthesis of cell wall mucopeptide. Sulbactam, a beta-lactamase inhibitor, irreversibly inhibits many beta-lactamases that occur in resistant bacteria strains. Chemistry Ampicillin and sulbactam are linked via a methylene group, forming two ester bonds (or more accurately acylal bonds). Sultamicillin is used in form of the tosylate salt. References Penicillins Codrugs Formals Pfizer brands