Sulbactam is a beta-lactamase inhibitor. The active ingredient extends the spectrum of action of beta-lactam antibiotics (also ß-lactam antibiotics) but has only a weak antibacterial effect.
What is sulbactam?
As a drug, sulbactam belongs to the group of ß-lactamase inhibitors and is a synthetic penicillinic acid sulfone. It is used in combination with ß-lactam antibiotics, whose action it extends. The chemical structure is the same, but the bacterial effect is weak. The use of sulbactam in combination with ß-lactam antibiotics results in much greater therapeutic safety than would be the case with monotherapy alone. In Germany, the drug is marketed under the trade names Combactam (monopreparation) and Ampicillin/Sulbactam, Ampicillin comp, and Unacid (combination preparations).
Pharmacologic effects on the body and organs
Sulbactam inhibits many forms of ß-lactamases produced by bacteria. However, the ß-lactamase “ampC cephalosporinase,” which is produced by Enterobacter, Citrobacter, Pseudomonas aeruginosa, and Serratia, among others, is not inhibited. Irreversible binding of sulbactam to the enzyme ß-lactamase occurs, preventing the enzyme from functioning. This prevents inactivation of the antibiotic so that the antibiotic effect can be exerted on the bacterium. In the digestive tract, sulbactam can be virtually unabsorbed. For this reason, it is usually administered parenterally via a short infusion. Immediately after the end of an infusion lasting 15 minutes, the maximum serum concentration of sulbactam is reached. In addition, bioavailability is 99 percent when injected into muscle, and absorption is almost complete and reliable about 30 to 60 minutes after drug administration. Sulbactam distributes well in tissues and body fluids. Distribution is limited only in the cerebrospinal fluid, although the effect is increased if inflammation is present there. Among the ß-lactamase inhibitors, sulbactam has the greatest affinity, and plasma protein formation is 38 percent. The approximate plasma half-life of sulbactam is one hour. Sulbactam is excreted primarily by tubular secretion (active excretion of substances such as urea and ureic acid and ammonia into the primary urine) and glomerular filtration (ultrafiltration of the blood in the renal corpuscles, material separation of blood and primary urine). There is no metabolism of sulbactam, so excretion is primarily by the kidneys.
Medical use and use for treatment and prevention.
Sulbactam supports the action of antibiotics. By itself, it has neither bactericidal nor bacteriostatic effects. Rather, it inhibits the enzyme ß-lactamase, which is produced by some bacteria and is capable of cleaving the ß-lactam ring in antibiotics (e.g., penicillin, cephalosporin). The antibiotic becomes ineffective due to the cleavage of the chemical structure. Administration of sulbactam restores the antibiotic‘s effectiveness. Sulbactam is administered parenterally before the antibiotic. This in turn should have a similar half-life. The amount of the dose depends on the sensitivity of the pathogen and usually ranges from 0.5 to 1.0 grams of sulbactam. The maximum daily dose is four grams. In patients with renal dysfunction, the dose must be adjusted accordingly. Prescription of sulbactam is not indicated if hypersensitivity to ß-lactam antibiotics is present. Sulbactam should also not be used in children under one year of age, as its effects at this age have not been fully elucidated. Sulbactam should not be administered without the concomitant administration of a ß-lactam antibiotic, as it does not have an intrinsic effect. Embryotoxic and teratogenic effects have not been demonstrated in animal studies. However, there is insufficient experience for use in humans. It has been clarified that the drug passes into breast milk, although no damage has yet been observed in infants. During pregnancy and lactation, sulbactam should therefore be administered only after careful indication and consideration of the benefits and risks.
Risks and Side Effects
As with any drug, undesirable side effects may occur with the administration of sulbactam.Side effects include allergic reactions (e.g., skin rash, increased eosinophil granulocyte count, anaphylactic shock), digestive tract disorders, local reactions at the injection site, interstitial nephritis (inflammatory disease of the kidneys), and an increase in liver enzymes due to the combination with the antibiotic. In addition, there may be an increase in the side effects of the antibiotic. Precipitation, turbidity, and discoloration occur with concomitant use of drugs such as aminoglycosides and metronidazole. These interactions are also expected with parenteral tetracycline derivatives (e.g., doxycycline, oxytetracycline, and rolitetracycline), with norepinephrine, sodium pentothal, prednisolone, and suxamethonium chloride, so the individual drugs must be administered separately.
