Legal Classification of Medication
POM
Allopurinol tablets can only be obtained in accordance with a prescription given by an appropriate practitioner and therefore the legal status of the medication is prescription only medication (POM).
Allopurinol is available in tablet form. The tablets come in 100mg and 300mg strengths.
Class of Drug
Allopurinol is in a class of medications called xanthine oxidase inhibitors.
Indications
Prevention of gout and of uric acid and calcium oxalate stones.
Prevention of increased amounts of uric acid in blood associated with cancer chemotherapy.
How does it work?
Gout is a condition in which uric acid crystals are deposited in tissues, especially in the joints, provoking an inflammatory response that manifests as an extremely painful acute joint pain. Uric acid crystallizes in the tissues when the plasma (a constituent of blood) urate levels are high, as a result of either excessive production or reduced kidney excretion. Allopurinol stops the enzyme called xanthine oxidase, which converts purines (molecules released from the breakdown of DNA) into uric acid, thus reducing uric acid production.
How is it taken?
Allopurinol should be introduced at a low dose, i.e. 100mg per day after food, to reduce the risks of adverse reactions. The dose should only be increased if the serum urate levels are not satisfactory. Extra precaution should be exercised in patients with poor kidney function as a reduction in dose may be necessary.
Pregnancy and Breast feeding
There is inadequate evidence of safety of allopurinol in human pregnancy, although it has been in wide use for many years without apparent ill consequence.
Use in pregnancy only when there is no safer alternative and when the disease itself carries risk for the mother or unborn child.
Allopurinol can be safely be used in nursing mothers as there is no data concerning the adverse effects on the breast fed baby.
Contra-indications
Allopurinol should not be used in treatment of acute gout, as it will initially worsen the symptoms.
Side-effects
Skin reactions are the most common reactions and may occur anytime during the treatment. Allopurinol should be withdrawn immediately if any skin reactions occur. After recovery from skin reactions allopurinol may be reintroduced at a small. If skin reaction occurs after reintroducing the medication the therapy should be permanently stopped as more severe hypersensitivity can occur. Other side-effects include:
