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Allopurinol: Indications, Dosing, Side Effects and Interactions
Allopurinol clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 4 min read
Allopurinol: Indications, Dosing, Side Effects and Interactions
Allopurinol clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Prophylaxis of gout and of uric acid and calcium oxalate renal stones,Prophylaxis of hyperuricaemia associated with cancer chemotherapy**
- **Adult** (By Mouth): Initially 100 mg once daily, to be taken preferably after food, for maintenance adjust dose according to plasma- or urinary-uric acid concentration.
**Prophylaxis of gout and of uric acid and calcium oxalate renal stones (usual maintenance in mild conditions),Prophylaxis of hyperuricaemia associated with cancer chemotherapy (usual maintenance in mild conditions)**
- **Adult** (By Mouth): 100-200 mg once daily, to be taken preferably after food.
**Prophylaxis of gout and of uric acid and calcium oxalate renal stones (usual maintenance in moderately severe conditions),Prophylaxis of hyperuricaemia associated with cancer chemotherapy (usual maintenance in moderately severe conditions)**
- **Adult** (By Mouth): 300-600 mg once daily, to be taken preferably after food, if once-daily dose exceeds 300 mg consider dividing the dose to reduce gastro-intestinal intolerance.
**Prophylaxis of gout and of uric acid and calcium oxalate renal stones (usual maintenance in severe conditions),Prophylaxis of hyperuricaemia associated with cancer chemotherapy (usual maintenance in severe conditions)**
- **Adult** (By Mouth): 700-900 mg daily in 3 divided doses, to be taken preferably after food.
**Prophylaxis of hyperuricaemia associated with cancer chemotherapy, Prophylaxis of hyperuricaemic nephropathy, Enzyme disorders causing increased serum urate e.g Lesch-Nyhan syndrome for allopurinol**
- **Child 1 month-14 years** (By mouth): 10-20 mg/kg once daily (max. per dose 400 mg), to be taken preferably after food, if once-daily dose exceeds 300 mg consider dividing the dose to reduce gastro-intestinal intolerance.
- **Child 15-17 years** (By mouth): Initially 100 mg once daily, to be taken preferably after food, increased if necessary up to 300 mg 3 times a day, to be taken preferably after food, dose to be adjusted according to response.
Cautions
Ensure adequate fluid intake (2-3 litres/day); for hyperuricaemia associated with cancer therapy, allopurinol treatment should be started before cancer therapy; thyroid disorders Cautions, further information Initiation or up-titration of treatment may precipitate an acute attack of gout-for information on prophylaxis see Gout
Contraindications
Not a treatment for acute gout but continue if attack develops when already receiving allopurinol, and treat attack separately
Side effects
Common or very common Rash (discontinue therapy; if rash mild re-introduce cautiously but discontinue immediately if recurrence) Uncommon Hypersensitivity; nausea; vomiting Rare or very rare Agranulocytosis; alopecia; angina pectoris; angioedema; angioimmunoblastic T-cell lymphoma; aplastic anaemia; asthenia; ataxia; boil; bradycardia; cataract; coma; depression; diabetes mellitus; drowsiness; erectile dysfunction; fever; gastrointestinal disorders; gynaecomastia; haemorrhage; hair colour changes; headache; hepatic disorders; hyperlipidaemia; hypertension; infertility male; maculopathy; malaise; oedema; paraesthesia; paralysis; peripheral neuropathy; severe cutaneous adverse reactions (SCARs); skin reactions; stomatitis; taste altered; thrombocytopenia; vertigo; visual impairment
Interactions
**Severe interactions:**
- Serum concentrations of 6-mercaptopurine or azathioprine may reach toxic levels with consequent life-threatening pancytopenia and myelosuppression when these medicinal products are given...
**Other interactions (23):**
- 6 -Mercaptopurine and Azathioprine Azathioprine is metabolised to 6-mercaptopurine, which is inactivated by the action of xanthine oxidase.
- When 6-mercaptopurine or azathioprine is given concurrently with allopurinol, a xanthine oxidase inhibitor, inhibition of xanthine oxidase will prolong their activity.
- Therefore, concomitant use of allopurinol with 6-mercaptopurine or azathioprine should be avoided.
- If it is determined that co-administration with 6-mercaptopurine or azathioprine is clinically needed, dosing should be reduced to one quarter (25%) of the usual dose of 6-mercaptopurine or...
- Vidarabine (Adenine Arabinoside) Evidence suggests that the plasma half-life of vidarabine is increased in the presence of allopurinol.
- Salicylates and uricosuric agents Oxipurinol, the major metabolite of allopurinol and itself therapeutically active, is excreted by the kidney in a similar way to urate.
Pregnancy
Toxicity not reported. Manufacturer advises use only if no safer alternative and disease carries risk for mother or child.
Breast feeding
Present in milk-not known to be harmful.
Hepatic impairment
Manufacturer advises monitor liver function periodically during early stages of therapy. Dose adjustments Manufacturer advises reduce dose.
Renal impairment
Use with caution (risk of accumulation). M Increased risk of hypersensitivity skin reactions. Dose adjustments Max. initial dose 100 mg daily, increased only if response inadequate; in severe impairment, reduce daily dose below 100 mg, or increase dose interval; if facilities available, adjust dose to maintain plasma-oxipurinol concentration below 100 micromol/litre. M
Medicinal forms
Solution
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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