(1991; 44 pages) [French] [Spanish]
Group: antimycobacterial agent
Capsule or tablet 150 mg, 300 mg
A semisynthetic derivative of rifamycin, a complex macrocyclic antibiotic that inhibits ribonucleic acid synthesis in a broad range of microbial pathogens.
Rifampicin is lipid-soluble. Following oral administration, it is rapidly absorbed and distributed throughout the cellular tissues and body fluids; if the meninges are inflamed, significant amounts enter the cerebrospinal fluid. A single dose of 600 mg produces a peak serum concentration of about 10 micrograms/ml in 2-4 hours, which subsequently decays with a half-life of 2-3 hours. It is extensively recycled in the enterohepatic circulation, and metabolites formed by deacetylation in the liver are eventually excreted in the faeces.
Since resistance readily develops, rifampicin must always be administered in combination with other effective antimycobacterial agents.
Treatment of paucibacillary and multibacillary leprosy in combination with other antileprosy drugs.
Dosage and administration
Administration of rifampicin should always be supervised. The drug should preferably be given at least 30 minutes before meals, since absorption is reduced when it is taken with food.
Paucibacillary leprosy (in combination with dapsone)
Adults: 600 mg once a month for at least 6 months.
Children: 10 mg/kg once a month for at least 6 months.
Multibacillary leprosy (in combination with dapsone and clofazimine)
Adults: 600 mg once a month for at least 2 years.
Children: 10 mg/kg once a month for at least 2 years.
• Known hypersensitivity to rifamycins.
• Hepatic dysfunction.
Serious immunological reactions resulting in renal impairment, haemolysis or thrombocytopenia are on record in patients who resume taking rifampicin after a prolonged lapse of treatment. In this rare situation it should be immediately and definitively withdrawn.
Careful monitoring of liver function is required in the elderly and in patients who are alcohol-dependent or have hepatic disease.
Patients should be warned that treatment may produce a reddish discoloration of urine, tears and saliva and that contact lenses may be irreversibly stained.
Use in pregnancy
Since leprosy is exacerbated during pregnancy it is important that treatment should be continued.
Vitamin K should be administered to the infant at birth because of the risk of postnatal haemorrhage.
Rifampicin is well tolerated by most patients at currently recommended dosages, although gastrointestinal intolerance can be unacceptably severe. Other adverse effects (rashes, fever, influenza-like syndrome and thrombocytopenia) are more likely to occur during intermittent (three times weekly) administration, as sometimes used in the treatment of tuberculosis. Temporary oliguria, dyspnoea and haemolytic anaemia have also occasionally been reported in these circumstances, but they have never been associated with the monthly dosage schedules advocated in leprosy.
Moderate rises in serum concentrations of bilirubin and transaminases, which are common at the outset of treatment, are often transient and without clinical significance. However dose-related hepatitis can occur, which is potentially fatal. It is consequently important not to exceed the maximum recommended daily dose of 10 mg/kg (600 mg).
Rifampicin is a potent inducer of hepatic enzymes when it is administered daily. The dosage of other drugs metabolized in the liver may need to be increased when they are taken concomitantly. These include corticosteroids, steroid contraceptives, oral hypoglycaemic agents, oral anticoagulants, phenytoin, cimetidine, quinidine, ciclosporin and digitalis glycosides. However, this effect is less pronounced when rifampicin is administered monthly.
Because enzyme induction reduces the reliability of steroid contraceptives, patients should be strongly advised to use a nonhormonal method of birth control throughout treatment and for at least 1 month subsequently.
Biliary excretion of radiocontrast media and sulfobromophthalein sodium may be reduced and microbiological assays for folic acid and vitamin B12 disturbed.
Gastric lavage may be of value if undertaken within a few hours of ingestion. Very large doses may depress central nervous function. There is no specific antidote and treatment is supportive.
Capsules and tablets should be kept in tightly closed containers, protected from light.