Allopurinol

The Basics

What is Allopurinol?

Used to decrease high blood uric acid levels, and specifically used to prevent gout, types of kidney stones and for the high uric acid levels that can occur with chemotherapy.

Brand names for Allopurinol

Zyloprim

How Allopurinol is classified

Antigout Agents, Enzyme Inhibitors, Gout Suppressants

Allopurinol During Pregnancy

Allopurinol pregnancy category

Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.

What we know about taking Allopurinol while pregnant

Reproductive studies have been performed in rats and rabbits at doses up to twenty times the usual human dose (5 mg/kg per day), and it was concluded that there was no impaired fertility or harm to the fetus due to allopurinol. There is a published report of a study in pregnant mice given 50 or 100 mg/kg allopurinol intraperitoneally on gestation days 10 or 13. There were increased numbers of dead fetuses in dams given 100 mg/kg allopurinol but not in those given 50 mg/kg. There were increased numbers of external malformations in fetuses at both doses of allopurinol on gestation day 10 and increased numbers of skeletal malformations in fetuses at both doses on gestation day 13. It cannot be determined whether this represented a fetal effect or an effect secondary to maternal toxicity. There are, however, no adequate or well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed. Experience with ZYLOPRIM (allopurinol) during human pregnancy has been limited partly because women of reproductive age rarely require treatment with ZYLOPRIM (allopurinol) . There are two unpublished reports and one published paper of women giving birth to normal offspring after receiving ZYLOPRIM (allopurinol) during pregnancy.

Taking Allopurinol While Breastfeeding

What are recommendations for lactation if you're taking Allopurinol?

Limited information indicates that a maternal doses of allopurinol of 300 mg daily provides near-therapeutic dose and plasma levels in an exclusively breastfed infant. If allopurinol is required by the mother, it is not a reason to discontinue breastfeeding, but exclusively breastfed infants should be monitored if this drug is used, including observation for allergic reactions (such as rash) and periodic CBC and differential blood counts. Lesinurad, which is available in the combination product Duzallo, has not been studied in nursing mothers.

Maternal / infant drug levels

Limited information indicates that a maternal doses of allopurinol of 300 mg daily provides near-therapeutic dose and plasma levels in an exclusively breastfed infant. If allopurinol is required by the mother, it is not a reason to discontinue breastfeeding, but exclusively breastfed infants should be monitored if this drug is used, including observation for allergic reactions (such as rash) and periodic CBC and differential blood counts. Lesinurad, which is available in the combination product Duzallo, has not been studied in nursing mothers.

Possible effects of Allopurinol on milk supply

Relevant published information was not found as of the revision date.

Possible alternatives to Allopurinol