Rifampicin and Isoniazid Tablets Anti-tuberculous
COMPOSITION:
Each Tablet contains 150 mg rifampicin and 75 mg isoniazid.
PHARMACOLOGICAL ACTION:
Rifampicin is an antibiotic with bactericidal activity against M. tuberculosis. It has the ability to kill intracellular and extracellular micro-organisms.
Rifampicin is about 89% protein bound and has a half-life of 2 - 5 hours.
Isoniazid is bacteriostatic for resting bacilli, but is bactericidal for rapidly dividing organisms. Isoniazid is not bound appreciably to plasma proteins.
INDICATIONS:
Rifampicin and isoniazid is indicated for the treatment of all forms of tuberculosis, including fresh, advanced and chronic cases.
CONTRA-INDICATIONS:
Rifampicin and isoniazid is contra- indicated in jaundice, acute porphyria and in patients with a history of hypersensitivity to rifamycins or isoniazid. Rifampicin ran cause thrombocytopenia and purpura, usually with intermittent tuberculosis regimens, further administration is contra-indicated.
Rifampicin and isoniazid have been reported to cross the placental barrier and a appear in cord blood. Rifampicin and isoniazid should be used in pregnant women or in women of childbearing potential only if the potential benefit justifies the potential risk to the foetus. During the first trimester of pregnancy, Rifampicin and isoniazid must only be used in life-threatening conditions and where no other suitable alternative treatment is available.
DOSAGE AND DIRECTIONS FOR USE:
Other antituberculosis agents may be given concurrently until the susceptibility of the infecting organism to rifampicin and isoniazid has been confirmed. Adult patients should be given the following daily dose at least 30 minutes before a meal or 2 hours after a meal:
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Patients weighing less than 50 kg: 3 tablets (450 mg rifampicin and 225 mg isoniazid). |
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Patients weighing 50 kg or greater: 4 tablets (600 mg rifampicin and 300 mg isoniazid). |
The choice of either the 450 mg or 600 mg dose of rifampicin should be based on a schedule of 8 - 12 mg/kg body mass. Doses towards the lower end of this range are recommended for frail and elderly patients. A dose of 8 mg/kg body mass should not be exceeded in patients with impaired liver function. Rifampicin and isoniazid Tablets is unsuitable for children under 12 years of age.
SIDE EFFECTS AND SPECIAL PRECAUTIONS:
Rifampicin and isoniazid is a combination of two drugs, each of which has been associated with liver dysfunction. Patients with current chronic liver disease, impaired liver function or severe renal dysfunction should only be given Rifampicin and isoniazidp in cases of necessity and then with caution and under strict medical supervision.
Rifampicin:
Cutaneous reactions, which are self- limiting, may occur and do not appear to be hypersensitivity reactions.
Gastro- intestinal reactions consist of anorexia, nausea, vomiting, abdominal discomfort, diarrhoea and pseudomembranous colitis.
Disseminated intravascular coagulation has also been reported.
Isoniazid:
Polyneuritis associated with isoniazid presenting as paraesthesia, muscle weakness, loss of tendon reflexes, etc. may occur. Various haematological disturbances including eosinophilia, agranulocytosis, thrombocytopenia and anaemia may occur. Gastrointestinal reactions may include nausea, vomiting and epigastric distress. High doses of isoniazid can cause convulsions. The frequency of seizures may be increased in patients with epilepsy.
STORAGE INSTRUCTIONS:
Store below 25°C in a dry place, out of reach of children.
