Phenylbutazone has 22 known drug interactions based on U.S. FDA drug labeling data. 3 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Levonorgestrel/Ethinyl Estradiol And Ethinyl Estradiol, Methotrexate, Norethindrone. Patients taking Phenylbutazone should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 22
- Major
- 3
- Moderate
- 17
- Minor
- 2
Major (3)
- Phenylbutazone + Levonorgestrel/Ethinyl Estradiol And Ethinyl Estradiol— Increases metabolism of contraceptive steroids, reducing contraceptive effectiveness and potentially resulting in uninte…
- Phenylbutazone + Methotrexate— May increase methotrexate toxicity by displacing the drug from serum albumin binding.
- Phenylbutazone + Norethindrone— May reduce contraceptive effectiveness and result in unintended pregnancy or breakthrough bleeding by increasing metabol…
Moderate (17)
- Phenylbutazone + Cholestyramine Light— Cholestyramine may delay or reduce the absorption of phenylbutazone.
- Phenylbutazone + Cholestyramine Powder For Suspension— Cholestyramine may delay or reduce the absorption of phenylbutazone.
- Phenylbutazone + Choleystyramine Light— Cholestyramine may delay or reduce absorption of phenylbutazone.
- Phenylbutazone + Desogestrel And Ethinyl Estradiol And Ethinyl Estradiol— Similar association with reduced efficacy and breakthrough bleeding suggested, though less marked than with rifampin.
- Phenylbutazone + Estradiol/Norethindrone Acetate Transdermal System— CYP3A4 inducer that may reduce plasma concentrations of estrogens, possibly decreasing therapeutic effects and altering …
- Phenylbutazone + Ethynodiol Diacetate And Ethinyl Estradiol— Similar association with reduced efficacy, though less marked than rifampin.
- Phenylbutazone + Etodolac— Phenylbutazone increases the free fraction of etodolac by approximately 80%. Coadministration is not recommended.
- Phenylbutazone + Heparin Sodium— Interferes with platelet aggregation and may induce bleeding. Use with caution; dose reduction of antiplatelet agent or …
- Phenylbutazone + Methylphenidate Hydrochloride— Methylphenidate may inhibit metabolism of phenylbutazone. Downward dosage adjustments may be required.
- Phenylbutazone + Norethindrone Acetate, Ethinyl Estradiol And Ferrous Fumarate— Phenylbutazone may reduce contraceptive effectiveness and increase incidence of breakthrough bleeding.
- Phenylbutazone + Norethindrone Acetate/Ethinyl Estradiol— Reduction in contraceptive effectiveness and increased incidence of breakthrough bleeding have been suggested.
- Phenylbutazone + Norethindrone And Ethinyl Estradiol— Associated with reduced contraceptive efficacy and increased breakthrough bleeding.
- Phenylbutazone + Penicillin G— Competes with penicillin G for renal tubular secretion, prolonging serum half-life.
- Phenylbutazone + Penicillin G Potassium— Competes with penicillin G for renal tubular secretion, prolonging serum half-life of penicillin.
- Phenylbutazone + Penicillin G Sodium— Competes with penicillin G for renal tubular secretion, prolonging serum half-life of penicillin.
- Phenylbutazone + Salicylic Acid— Salicylate inhibits the uricosuric effect of phenylbutazone.
- Phenylbutazone + Salicylic Acid 10%— Salicylate inhibits the uricosuric effect of phenylbutazone.
Minor (2)
- Phenylbutazone + Prazosin— Prazosin has been administered without adverse drug interaction with phenylbutazone in limited clinical experience.
- Phenylbutazone + Prazosin Hydrochloride— Administered without adverse drug interaction in limited clinical experience.