The following points highlight the two main drugs used for the treatment of leprosy. The drugs are: 1. Dapsone 2. Clofazimine.
Drug # 1. Dapsone:
Dapsone is the principal drug to treat leprosy and is chemically related to sulfonamides. It is bacteriostatic for M. leprae, and its mechanism of action is similar to that of sulfonamides. Dapsone is slowly, but completely absorbed from the gut. It undergoes intestinal reabsorption from the bile, resulting in a sustained level of the drug in the circulation. It is concentrated in skin (especially lepromatous skin), muscle, liver and kidney. It is metabolized and excreted by kidney.
Side effects are generally uncommon. The most common side effects include hemolysis, methemoglobinemia, nausea, vomiting, rashes and anorexia. Lepra reactions (neurotic pain or erythema nodosum leprosum) should be treated with prednisolone or aspirin or chloroquine. The drug should be discontinued, if dapsone syndrome (rash with fever and eosinophilia) develops.
Drug # 2. Clofazimine:
Clofazimine is a dye with leprostatic and anti-inflammatory properties. It binds to mycobacterium DNA, thereby inhibiting template function. Clofazimine is orally active, 50% of an oral dose reaches the systemic circulation. It is lipophilic and accumulates in adipose tissue and reticuloendothelial cells. The elimination half-life after repeated oral dosing is 70 days.
Clofazimine, red-purple dye, is taken up and concentrated by macrophages of the skin, causing increased skin pigmentation. It is also deposited in the small intestines, where at high concentrations it causes segmental thickening associated with crampy pain and diarrhea. If clofazimine is unacceptable to patients, minocyclin or ofloxacin should be substituted.