Allopurinol

Also indexed as: Apo-Allopurinol®, Caplenal®, Cosuric®, Lopurim®, Rimapurinol®, Xanthomax®, Zyloprim®, Zyloric®

Allopurinol is a xanthine oxidase inhibitor used to prevent gout and to lower blood levels of uric acid in certain people taking drugs for cancer.

Summary of Interactions with Vitamins, Herbs, and Foods
In some cases, an herb or supplement may appear in more than one category, which may seem contradictory. For clarification, read the full article for details about the summarized interactions.

Beneficial May be Beneficial: Supportive interaction—Taking these supplements may support or otherwise help your medication work better.

L-tryptophan
Check Check: Other—Before taking any of these supplements or eating any of these foods with your medication, read this article in full for details.

L-carnitine

Vitamin D
Depletion or interference

None known
Side effect reduction/prevention

None known
Reduced drug absorption/bioavailability

None known
Adverse interaction

None known

An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.

Interactions with Dietary Supplements

Vitamin D
Individuals with gout have low blood concentration of the active form of vitamin D (1,25 dihydroxycholecalciferol), and allopurinol corrects this problem.1

L-Carnitine
People who have Duchenne muscular dystrophy have low levels of L-carnitine in their muscles. Allopurinol restores L-carnitine to normal levels, resulting in improved muscle strength.2 Whether L-carnitine supplementation might improve this effect of allopurinol has not been investigated.

L-tryptophan
In a preliminary study, seven of eight individuals with severe mental depression showed improvement when they took L-tryptophan and allopurinol;3 of these seven, five experienced full remission. Controlled research is necessary to determine whether this combination might be more effective for severe depression than standard treatment.

Interactions with Foods and Other Compounds

Food
Allopurinol may be taken with food to prevent stomach upset.4

Protein
Compared with people on high-protein diets, people on low-protein diets excrete less allopurinol, resulting in a threefold increase in the time it takes for the drug to be removed from the body.5 Vegetarians and those who eat low-protein diets (20 grams of protein a day or less) should discuss this possible interaction with their healthcare practitioner before taking allopurinol.

Alcohol
According to animal research, alcohol reduces the activity of antioxidant systems involving vitamin E, vitamin C, and selenium, leading to tissue damage in the cerebellum; however, allopurinol reverses this effect.6 Drinking alcoholic beverages also increases the removal of allopurinol from the body, thereby reducing the effectiveness of the drug.7 Therefore, people taking allopurinol should avoid alcohol.

References

1. Takahashi S, Yamamoto T, Moriwaki Y, et al. Decreased serum concentrations of 1, 25 (OH)2-vitamin D3 in patients with gout. Metabolism 1998;47:336–8.

2. Camina F, Novo-Rodriguez MI, Rodriguez-Segade S, Castro-Gago M. Purine and carnitine metabolism in muscle of patients with Duchenne muscular dystrophy. Clin Chim Acta 1995;243:151–64.

3. Stern SL, Mendels J. Drug combinations in the treatment of refractory depression: a review. J Clin Psychiatry 1981;42:368–73.

4. Threlkeld DS, ed. Central Nervous System Drugs, Antiemetic/Antivertigo Agents, Miscellaneous, Agents For Gout. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparison, 1999, 1523–7.

5. Murrell GA, Rapeport WG. Clinical pharmacokinetics of allopurinol. Clin Pharmacokinet 1986;11:343–53.

6. Nordmann R, Ribiere C, Rouach H. Ethanol-induced lipid peroxidation and oxidative stress in extrahepatic tissues. Alcohol Alcohol 1990;25:231–7.

7. Kaneko K, Fujimori S, Ishizuka I, Akaoka I. Effects of ethanol on metabolism of the hypourecemic agents allopurinol and benzbromarone. Clin Chim Acta 1990;193:181–6.