Phenylbutazone

Brand Names: Apo-Phenylbutazone, Apotex

Clinical Names: Phenylbutazone

Summary

generic name: Phenylbutazone

trade names: Apo-Phenylbutazone®, Apotex®

type of drug: Nonsteroidal anti-inflammatory drug (NSAID); anti-inflammatory; antiarthritic.

used to treat: Painful arthritic or musculoskeletal syndromes, such as osteoarthritis, arthritis, bursitis, posterior weakness or paralysis, rheumatism, inflammation of the skin and other soft tissues.

overview of interactions:
• nutrient affected by drug: Folic Acid




Interactions

nutrient affected by drug: Folic Acid

• mechanism: Phenylbutazone impairs folate absorption and inhibits the membrane transport of folate compounds.
(Hodges R. 1980:323-331.)

• nutritional support: Individuals who take phenylbutazone over an extended period of time would benefit from folate supplementation to protect against depletion of folate. This could be in the form of a folate supplement or as part of a multivitamin/mineral formula. Folic aid supplementation at levels of 400 mcg per day would compensate for any drug depletion effect. Eating a diet rich in dark green leafy vegetables can also provide a healthy source of folic acid. Too much folic acid is not a concern in these situations as the nutrient is essentially non-toxic.

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The information presented in Interactions is for informational and educational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, case reports, and/or traditional usage with sources as cited in each topic. The results reported may not necessarily occur in all individuals and different individuals with the same medical conditions with the same symptoms will often require differing treatments. For many of the conditions discussed, treatment with conventional medical therapies, including prescription drugs or over-the-counter medications, is also available. Consult your physician, an appropriately trained healthcare practitioner, and/or pharmacist for any health concern or medical problem before using any herbal products or nutritional supplements or before making any changes in prescribed medications and/or before attempting to independently treat a medical condition using supplements, herbs, remedies, or other forms of self-care.


References

Branda RF, Nelson NL. Inhibition of 5-methyltetrahydrofolic acid transport by amphipathic drugs. Drug Nutr Interact 1981;1(1):45-53.
Abstract: Numerous chemically unrelated drugs after the membrane transport of folate compounds. To investigate drug structure-activity relationships, we measured the effect of amphipathic drugs (that is, compounds with polar-apolar character) on 5-methyltetrahydrofolic acid permeability of human erythrocytes. All drugs tested were inhibitory, but only compounds that exist at least partially in the anionic form were highly active. Ethacrynic acid, sulfinpyrazone, phenylbutazone, sulfasalazine, and furosemide were effective transport inhibitors in micromolar concentrations. In contrast, compounds that are capable of forming cations at physiologic pH, such as chlorpromazine, procaine, tetracaine, and papaverine, were inhibitory only in millimolar concentrations or caused hemolysis before major inhibition was seen. Inhibitory activity correlated with drug dissociation constant (r = 0.87). A double-reciprocal plot analysis of drug effect on 5-methyltetrahydrofolic acid transport showed changes in both Km and Vmax (indicating a mixture of competitive and noncompetitive inhibition) by ethacrynic acid, sulfasalazine, and phlorizin. Inhibitory activity of a series of eight phenoxyacetic derivatives, including ethacrynic acid, correlated highly with measurements of liposolubility (r = 0.87) but only weakly with the Hammet substituent constant (r = 0.56). These results suggest that the effect of amphipathic drugs on 5-methyltetrahydrofolic acid transport is influenced by drug pKa and by the presence of hydrophobic substituents, but is relatively independent of electron-attracting groups.

Hodges R. Drug-nutrient interaction. In: Nutrition in Medical Practice. Philadelphia: W.B. Saunders, 1980:323-331.

Muscat-Baron JM, Freeman DM. Toxic hepatitis following phenylbutazone therapy. Br J Clin Pract. 1966 Aug;20(8):437-439.