Product Information

Registration Status: Active

ALLOPURINOL TABLET 100mg is approved to be sold in Singapore with effective from 1991-08-05. It is marketed by BEACONS PHARMACEUTICALS PTE LTD, with the registration number of SIN05804P.

This product contains Allopurinol 100mg in the form of TABLET. It is approved for ORAL use.

This product is manufactured by BEACONS PHARMACEUTICALS PTE LTD in SINGAPORE.

It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.



A xanthine oxidase inhibitor that decreases uric acid production. It also acts as an antimetabolite on some simpler organisms. Allopurinol is considered a standard treatment of hyperuricemia associated with gout. In August 2017, an oral combination agent Duzallo was approved by FDA as a dual-mechanism treatment of hyperuricemia in patients with uncontrolled gout. Duzallo contains allopurinol and [DB11560], a recently FDA-approved URAT1 inhibitor indicated for the treatment of hyperuricemia associated with gout.


For the treatment of hyperuricemia associated with primary or secondary gout. Also indicated for the treatment of primary or secondary uric acid nephropathy, with or without the symptoms of gout, as well as chemotherapy-induced hyperuricemia and recurrent renal calculi.

Mechanism of Action

Allopurinol and its active metabolite, oxypurinol, inhibits the enzyme xanthine oxidase, blocking the conversion of the oxypurines hypoxanthine and xanthine to uric acid. Elevated concentrations of oxypurine and oxypurine inhibition of xanthine oxidase through negative feedback results in a decrease in the concentrations of uric acid in the serum and urine. Allopurinol also facilitates the incorporation of hypoxanthine and xanthine into DNA and RNA, leading to a feedback inhibition of de novo purin synthesis and a decrease in serum uric acid concentrations as a result of an increase in nucleotide concentration.


Approximately 80-90% absorbed from the gastrointestinal tract.


LD50=214 mg/kg (in mice)

Active Ingredient/Synonyms

1,5-Dihydro-4H-pyrazolo(3,4-d)pyrimidin-4-one | 1,5-Dihydro-4H-pyrazolo(3,4-d)pyrimidine-4-one | 1H-Pyrazolo(3,4-d)pyrimidin-4-ol | 4-HPP | 4-Hydroxy-1H-pyrazolo(3,4-d)pyrimidine | 4-Hydroxy-3,4-pyrazolopyrimidine | 4-Hydroxypyrazolo(3,4-d)pyrimidine | 4-Hydroxypyrazolopyrimidine | 4-Hydroxypyrazolyl(3,4-d)pyrimidine | 4'-Hydroxypyrazolol(3,4-d)pyrimidine | 4H-Pyrazolo(3,4-d)pyrimidin-4-one | Allopurinolum | Alopurinol | Allopurinol |

Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.


  1. Health Science Authority of Singapore - Reclassified POM
  2. Drugbank