The active ingredient aztreonam is a monobactam antibiotic. The drug is used to treat infections with aerobic gram-negative bacteria.
What is aztreonam?
Aztreonam is the name for an antibiotic that belongs to the group of monobactams. The drug has similar pharmacodynamic and pharmacokinetic properties to penicillin. Aztreonam exerts its effect exclusively against Gram-negative bacteria. The clinical relevance of the active ingredient is considered to be low in medicine, so that it is mostly used as a reserve antibiotic. Monobactams have no effect on Gram-positive bacteria. In Europe, aztreonam received its approval in the mid-1980s. As a dry substance, the drug is administered parenterally (past the intestine). As a monopreparation, the antibiotic, which is the only representative of the monobactams, is represented in German-speaking countries under the trade names Azactam and Cayston.
Pharmacologic action
In its chemical structure, aztreonam belongs to the subgroup of betalactam antibiotics. Penicillins are also part of this group. Thus, aztreonam has the property of binding to the same proteins to which penicillin can dock. The monobactam antibiotic is able to significantly disrupt the structure of bacterial cell walls. This in turn results in the dissolution of the bacterial cell. Aztreonam binds to the penicillin-binding protein and blocks it with its lactam ring in such a way that mucopeptides can no longer form compounds with each other. This results in a growth arrest, which helps aztreonam to achieve its bactericidal effect. In addition, aztreonam is effective against aerobic (oxygen-loving) gram-negative bacteria, including Pseudomonas aeruginosa. This germ is considered very dangerous and is difficult to treat, often causing life-threatening infections. The bioavailability of aztreonam is 100 percent. In the blood, 56 percent of the antibiotic binds to plasma proteins. The drug is metabolized by the liver. The plasma half-life is 1.7 hours on average. Subsequently, aztreonam is cleared from the body via the kidneys.
Medical use and application
Aztreonam is used primarily for the treatment of cystic fibrosis. This cystic fibrosis is a hereditary metabolic disease. An excess of viscous mucus is formed in the respiratory tract of the affected person. The mucus cannot be coughed up naturally, providing an ideal breeding ground for bacteria. For this reason, the risk of contracting an infection is considered to be particularly high in cystic fibrosis patients. Aztreonam is extremely effective in treating chronic pneumonia caused by the bacterium Pseudomonas aeruginosa. The antibiotic can be administered from the age of six. In combination with metronidazole, aztreonam is also used against infections within the abdominal cavity. Together with clindamycin, the monobactam antibiotic is considered helpful against gynecological infections. Aztreonam can be administered by inhalation or intravenous or intramuscular injection. In this case, the antibiotic is absorbed into the body bypassing the gastrointestinal tract.
Risks and side effects
Treatment with aztreonam sometimes causes side effects in some patients. These primarily include complaints of sore throat, pain in the throat, nasal congestion, whistling breath sounds, cough, breathing problems, and fever. It is not uncommon to also experience a bloody cough, runny nose, bronchial spasms, chest pain, joint pain, and rashes on the skin. Pulmonary function tests show decreased values in some sufferers. In some cases, swelling of joints is noted. If aztreonam is administered via the vein, there is a risk of undesirable side effects such as allergic shock, severe skin reactions, pinpoint hemorrhages, bleeding in the subcutis, sweating, itching and urticaria. Aztreonam should not be used at all if the patient is hypersensitive to the monobactam antibiotic.Careful consideration by the treating physician is required if there is an allergy to betalactam antibiotics such as cephalosporins, penicillins or carbapenems, if the patient is prone to bloody cough or bronchial spasms when aerosols are administered, or if there is poor lung function or impaired kidney function. The same applies in the case of a pre-existing infestation with resistant germs such as Pseudomonas aeruginosa and Burkholderia cepacia. There are no findings to date on the administration of aztreonam during pregnancy. Nevertheless, it is recommended that the antibiotic be administered only if the physician considers it absolutely necessary. Because aztreonam passes into the child’s body only in small amounts during breastfeeding in the case of inhalation, its use is permitted during breastfeeding. In children under six years of age, aztreonam should not be administered because there is no evidence of its effect on young children. Interactions between aztreonam and other medications are not known. In addition, absorption of the active ingredient into the body is unlikely to occur with inhalation.
