Uricosurics.

Sulfinpyrazone [sulphinpyrazone]

The active ingredient is 1,2-Diphenyl-3,5-dioxo-4-(2-phenylsulphinylethyl)- pyrazolidine (= sulfinpyrazone B.P.) Each coated tablet contains 100 mg or 200 mg sulfinpyrazone.

Coated tablets.

Chronic, including tophaceous gout; recurrent gouty arthritis; hyperuricaemia.

Anturan is administered orally in tablet form with meals or milk.

Adults: 100-200mg daily increasing gradually (over the first two or three weeks) to 600mg daily (rarely 800mg), and maintained until the serum urate level has fallen within the normal range. Subsequent dosage should be reduced, to the lowest level which maintains serum urate within the normal range. Maintenance dose may be as low as 200mg daily. Reduced dose required in renal impairment. Not to be used in severe renal impairment.

Paediatric usage not established.

Acute attacks of gout. Treatment with Anturan should not be initiated during an acute attack of gout.

Gastric and duodenal ulcer (overt or case-history).

Known hypersensitivity to sulfinpyrazone and other pyrazolone derivatives. Sulfinpyrazone is contra-indicated in patients in whom attacks of asthma, urticaria, or acute rhinitis are precipitated by acetylsalicylic acid or by other drugs with prostaglandin-synthetase inhibiting activity.

Severe parenchymal lesions of the liver or kidneys (also in the case history). Porphyria. Blood dyscrasias (also in the case history). Haemorrhagic diatheses (e.g. blood coagulation disorders).

In the treatment of chronic gout salicylates antagonise the action of Anturan and should not be given concurrently.

During the early stages of treatment in patients with hyperuricaemia or gout, acute attacks of gout may be precipitated. To help prevent episodes of urolithiasis or renal colic, ensure adequate fluid intake and alkalinisation of the urine during initial stages of therapy.

Since Anturan may cause salt and water retention, caution is called for in patients with overt or latent heart failure.

For the early detection of a haematological abnormality, careful clinical supervision and full blood count should be done before and at regular intervals during treatment.

Use with caution in patients with impaired renal function.

In patients with an elevated plasma uric acid level and/or with a history of nephrolithiasis or renal colic, and also when resuming treatment after interruption of the medication, a cautious incremental dosage schedule should be adopted. As with any form of long-term uricosuric medication, renal function tests should be performed regularly, particularly in cases where there is pre-existing evidence of renal failure.

Since Anturan may potentiate the action of coumarin-type anticoagulants, frequent estimation of prothrombin time should be undertaken when these drugs are given concurrently, and the dosage of anticoagulant adjusted accordingly.

Anturan may also potentiate the action of other plasma protein binding drugs such as hypoglycaemic agents and sulphonamides, which may necessitate a modification in dosage.

Penicillins (e.g. penicillin G): Inhibition of tubular secretion may raise the plasma concentrations of penicillins.

Theophylline: Activation of microsomal liver enzymes and resultant acceleration of metabolism lowers the plasma concentration of theophylline.

Phenytoin: Displacement of phenytoin from its plasma protein-binding sites as well as inhibition of microsomal liver enzymes delays the metabolism of phenytoin, thus prolonging its half-life and raising its plasma concentration.

Substances affecting haemostasis: Such substances, e.g. non-steroidal antirheumatic drugs, may exert a synergistic effect on the blood coagulation system and thus increase the risk of haemorrhage.

Gastro-intestinal tract:

Frequent: mild transient gastro-intestinal upsets, such as nausea, vomiting, diarrhoea.

In isolated cases: gastro-intestinal bleeding and ulcers.

Urogenital system:

Rare: acute renal failure (mostly reversible), especially with high initial dosages.

In isolated cases: salt and water retention.

Skin:

Rare: allergic skin reactions (e.g. drug rash, urticaria).

Blood:

In isolated cases: leucopenia, thrombocytopenia, agranulocytosis, aplastic anaemia.

Liver:

In isolated cases: hepatic dysfunction (increase in transaminases and alkaline phosphatase), jaundice, and hepatitis

Amdipharm

(POM)

04 June 2009