Leprosy (Hansen's disease) is a chronic disease caused by Mycobacterium leprae; it affects the peripheral nervous system, the skin, and some other tissues. It is transmitted from person to person when bacilli are shed from the nose and skin lesions of infected patients, but most individuals are naturally immune, and symptoms are suppressed. For treatment purposes patients may be classified as having paucibacillary (PB) or multibacillary (MB) leprosy. The 2 forms may be distinguished by skin smears, but facilities are not always available to process them and their reliability is often doubtful.

Drugs recommended are dapsone, rifampicin and clofazimine.

A three - drug regimen is recommended for multibacillary leprosy (lepromatus, borderline-lepromatous, and borderline leprosy) and a two - drug regimen for paucibacillary leprosy (borderline tuberculoid, tuberculoid, and indeterminate).

Any patient with a positive skin smear should be treated with the multidrug therapy regimen for MB leprosy. The regimen for PB leprosy should never be given to a patient with MB leprosy. If diagnosis in a particular patient is not possible the multi drug therapy regimen for MB leprosy must be used.

Multibacillary leprosy (3 - drug regimen)

Multibacillary leprosy should be treated for at least 2 years. Treatment should be continued unchanged during both type I (reversal) or type II (erythema nodosum leprosum) reactions. During reversal reactions neuritic pain or weakness can herald the rapid on set of permanent nerve damage. Treatment with prednisolone (initially 40 - 60mg daily) should be instituted at once. Mild type II reactions may respond to aspirin or chloroquine. Severe type II reactions may require corticosteroids; thalidomide is also useful in men and post menopausal women who have become corticosteroid dependent, but it would be used under specialist supervision and it should never be used in women of child bearing potential (significant teratogenic risk). Increase doses of clofazimine 100mg 3 times daily for the first month with subsequent reductions, are also useful but may take 4 - 6 weeks to attain full effect.

Paucibacillary leprosy (2 - drug regimen)

Paucibacillary leprosy should be treated for 6 months. If treatment is interrupted the regimen should be recommended where it was left off to complete the full courses.

Neither the multibacillary nor the paucibacillary antileprosy regimen is sufficient to treat tuberculosis.

Dapsone
Tablet, 25mg, 50mg, 100mg
Injection, 20% in 50ml ampoule

Indications: - paucibacillary (PB) and multibacillary (MB) leprosy (see notes above)

Cautions: - cardiac or pulmonary disease; anaemia (treat severe anaemia before starting); G6PD deficiency (including breastfeeding affected infants); pregnancy; breast-feeding; porphyria.

Note: - on long term treatment patients and their carers should be told how to recognize blood disorders and advised to seek immediate medical attention if symptoms such as fever, sore throat, rash, mouth ulcers, purpura, bruising or bleeding develop.

Drug interactions: - rifamycins, amprenavir, and probenecid.

Contraindications: - hypersensitivity to sulfones; severe anaemia.

Side effects: - (dose-related and uncommon at doses used for leprosy), haemolysis, methaemoglobinaemia, neuropathy, allergic dermatitis (rarely including toxic epidermal necrolysis and Stevens-Johnson syndrome), anorexia, nausea, vomiting, tachycardia, headache, insomnia, psychosis, hepatitis, agranulocytosis; dapsone syndrome (rash with fever and eosinophilia) - discontinue immediately (may progress to exfoliative dermatitis, hepatitis, hypoalbuminaemia, psychosis and death)

Dose and Administration

Leprosy, 1 - 2mg/kg daily, see notes above

Storage: - at room temperature, in a well - closed, light - resistant containers.

Clofazimine
Capsule, 50mg, 100mg

Indications: - multibacillary (MB) leprosy; type II lepra reactions.

Cautions: - pre-existing gastrointestinal symptoms (reduce dose, increase dose interval or discontinue if symptoms develop during treatment); liver and renal impairment; pregnancy and breast-feeding; may discolour soft contact lenses.

Note: - Patients should be warned that Clofazimine might cause a reddish - brown discolouration of skin, conjunctiva, tears, sputum, sweat, urine, and faces.

Side effects: - reversible discoloration of skin, hair, cornea, conjunctiva, tears, sweat, sputum; symptoms including pain, nausea, vomiting and diarrhoea; severe mucosal and submucosal oedema with prolonged treatment with high doses - may be severe enough to cause sub acute small bowel obstruction.

Dose Administration

Leprosy, see notes above

Lepromatous lepra reactions, dosage increased to 300mg daily for max. of 3 months.

Rifampicin
Capsule, 150mg, 300mg, and 600mg

Indications: - Paucibacillary leprosy; multibacillary leprosy; tuberculosis (section 7.1.3)

Cautions, Drug interactions, Side effects, Contraindications; see under section 7.1.3.

Dose and Administrations: see notes above.