COMPOSITION: Each tablet contains 300 mg Allopurinol.
PHARMACOLOGICAL CLASSIFICATION: A 3.3 Antigout preparations.
PHARMACOLOGICAL ACTION: Allopurinol inhibits xanthine oxidase, the enzyme responsible for the terminal steps in uric acid biosynthesis.
INDICATIONS: Urinol is indicated for the treatment of gout and hyperuricaemia associated with other conditions. It reduces the concentration of uric acid in plasma with gradual resolution of tophi and reduces the risk of the formation of uric acid calculi. It may be effective in patients with impaired renal function.
Urinol is also used in the treatment of hyperuricaemia associatedwith leukaemia or resulting from radiotherapy or the use of anti-neoplastic agents such as mercaptopurine or during treatment with diuretics of the thiazide or similar type.
CONTRAINDICATIONS: Urinol is contra-indicated in patients who have exhibited serious adverse effects from the medication, lactating mothers, and children, except those with malignancy.
Not to be used in acute gout.
DOSAGE AND DIRECTIONS FOR USE: In gout, it is usual to commence with 50 mg twice daily and to increase this dose as required up to 200 to 400 mg daily in divided doses. In severe conditions, doses of up to 600 mg may be necessary.
In hyperuricaemia associated with leukaemia a suggested initial dose is 200 mg thrice daily commencing if possible 2 or 3 days before radiotherapy or the commencement of treatment with anti-neoplastic agents, and adjusted as requested to a maintenance dose usually of 300 to 400 mg daily.
For children the suggested initial dose is 8 mg per kg body mass daily.
Fluid intake should be sufficient to maintain daily urinary volume above 2 litres.
Dosage must be reduced in patients with renal impairment in proportion to the reduction inglomerular filtration.
SIDE-EFFECTS AND SPECIAL PRECAUTIONS: Reactions may include hypersensitivity responses of the skin and blood e.g. skin eruptions, fever, chills, leucopenia or leucocytosis and eosinophilia; arthralgia and vasculitis leading to renal and hepatic damage. These reactions may be severe, even fatal and patients with renal impairment or taking thiazide diuretics are at special risk. These reactions usually subside a few days after administration is stopped.
More serious allergic reactions may occur and include exfoliative rashes, the Stevens Johnson syndrome, and toxic necrolysis. Allopurinol should therefore be withdrawn immediately if a rash occurs.
Headache, drowsiness, alopecia, nausea, vomiting, abdominal pain, vertigo, peripheral neuritis, diarrhoea, and gastric irritation are noted but do not require that therapy be stopped. Cataract formation has been reported.
A possibility of xanthine stone formation exists in children with Lesch-Nyhan syndrome and can be minimised by alkalinisation of the urine and increasing daily fluid intake.
Allopurinol should not be used for the treatment of an acute attack of gout.
The inactivation of mercaptopurine and azathioprine is inhibited by allopurinol and the dosage of mercaptopurine must be reduced when the medicines are given concomitantly.
There may be an increase in the toxicity of cyclophosphamide and other anti-neoplastic medicines. Similarly allopurinol can reduce the clearance of theophylline and other xanthines and their dosage might have to be reduced to avoid toxicity.
Allopurinol should not be administered concomitantly with chlorpropamide since there may be competition in the renal tubule for the excretion of chlorpropamide. When renal function is poor this may lead to a prolonged chlorpropamide hypoglycaemic action.
KNOWN SYMPTOMS OF OVERDOSAGE AND PARTICULARS OF ITS TREATMENT: The most likely reaction would be gastro-intestinal intolerance.
Administer sufficient fluids to maintain maximum diuresis since this in turn facilitates excretion of allopurinol and its metabolites.
Treatment is symptomatic and supportive.
White, biconvex tablets, engraved with a mortar and pestle on one side, and bisected on the other, with a diameter of 11,11 mm.
PRESENTATION: 300 mg:Securitainers of 30 and 250 tablets.STORAGE INSTRUCTIONS: Keep container tightly closed. Store below 25°C.
KEEP OUT OF REACH OF CHILDREN.
REGISTRATION NUMBERS: 27/3.3/0498
NAME AND BUSINESS ADDRESS OF APPLICANT: Lennon Limited, 7 Fairclough Road, PORT ELIZABETH 6001
DATE OF PUBLICATION OF THIS PACKAGE INSERT: 18/08/1993