Capreomycin is a peptide antibiotic of the aminoglycoside group, derived from a species of bacteria called Streptomyces capreolus. It has potent bactericidal effects towards a broad range of gram-positive and gram-negative aerobic bacteria, including mycobacteria such as mycobacterium tuberculosis which causes the deadly disease tuberculosis.
Uses of capreomycin
Capreomycin is mainly used as an anti-mycobacterial agent, and is primarily used in the treatment of resistant tuberculosis. Tuberculosis has been known and feared since antiquity when there was no treatment and the disease would invariably lead to death, prompting mass fear and isolation of its victims. The first real hope for sufferers of tuberculosis came in 1944 when streptomycin was found to be effective against the disease.
The use of streptomycin marked a breakthrough where it became possible to finally treat and in most cases cure tuberculosis. Unfortunately, overuse of antibiotics like streptomycin and penicillin have lead to resistance in the bacteria they were once effective against, and many diseases including tuberculosis are now much harder to cure.
Capreomycin is used as a third line drug against tuberculosis in combination with cycloserine, viomycin, kanamycin and amikacin. It is given daily in a dosage of 1 gram by intravenous or intramuscular injection with at least one other third line drug and is only used when first and second line drugs are either ineffective or unavailable. Capreomycin and the other third line drugs have a high toxicity and a few unwanted side effects that can be serious.
Side effects of capreomycin
Capreomycin has a few dangerous side effects and is only used when the benefits will outweigh this danger. One of the greatest risks is that of severe nephrotoxicity, with 36 per cent of patients given the drug suffering some degree of kidney damage and urinary complaints. This can also lead to electrolyte imbalances such as hyperkalemia that cause other problems.
Like the other aminoglycosides, capreomycin is ototoxic and causes damage to hearing. This ototoxicity occurs in response to mitochondrial protein synthesis being disrupted, causing the production of free radicals that destroy the cochlear hair cells and damage the 8th cranial nerve which transmits sound signals to the brain. It is these hair cells that allow a person to detect sounds, and up to 11 per cent of patients receiving capreomycin will suffer from hearing loss.
In some patients, the use of capreomycin can also cause other side effects. Possible liver damage has been noted in some people, and the drug can cause a reduction in the amount of white blood cells, leading to an increased risk of infection. It is also possible to be allergic to the drug, or have a reaction due to cross-allergy with any of the other aminoglycosides which are all similar in structure.
Whilst the side effects are dangerous, when used appropriately, capreomycin is a useful and beneficial agent in the treatment of resistant tuberculosis and should always be taken under the guidance of an experienced doctor to ensure it is used correctly and this danger is minimised.