Piroxicam is used to treat rheumatoid arthritis and osteoarthritis. It is in a class of medications known as non-steroidal anti-inflammatory drugs (NSAIDs).
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.
 Avoid: Adverse interaction—Avoid these supplements when taking this medication because taking them together may cause undesirable or dangerous results. | Lithium* Potassium* |
 Check: Other—Before taking any of these supplements or eating any of these foods with your medication, read this article in full for details. | Folic acid* Willow* |
| Depletion or interference | None known |
| Side effect reduction/prevention | None known |
| Supportive interaction | None known |
| Reduced drug absorption/bioavailability | 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
Potassium
An 85-year-old man developed higher than normal blood levels of potassium following several months of treatment with piroxicam.1 Until more is known, people taking piroxicam for long periods should have their blood checked regularly for high potassium levels and may need to avoid high potassium intake with the guidance of a health practitioner.
Folic acid
Piroxicam may prevent inflammation by blocking the activity of enzymes that depend on folic acid.2 However, other studies show that people taking NSAIDs such as aspirin have lower than normal levels of folic acid in their red blood cells.3 Further research is needed to determine whether supplemental folic acid prevents a deficiency of the vitamin or indirectly reduces the beneficial effects of piroxicam.
Lithium
Lithium is a mineral that is present in some supplements and is also used in large amounts to treat mood disorders such as bipolar disorder (manic depression). Blood levels of lithium may increase in people taking NSAIDs and lithium supplements together (compared with lithium alone),4 possibly resulting in unwanted side effects such as diarrhea, nausea, muscle weakness, and lack of coordination. More research is needed to determine whether piroxicam specifically increases lithium blood levels. Until more is known, people should avoid lithium supplementation except when it is prescribed by a doctor.
Interactions with Herbs
Willow (Salix alba)
Willow bark contains salicin, which is related to aspirin. Both salicin and aspirin produce anti-inflammatory effects after they have been converted to salicylic acid in the body. Taking aspirin significantly lowers blood levels of piroxicam and increases the potential for adverse side effects.5 Though no studies have investigated interactions between willow bark and piroxicam, people taking the drug should avoid the herb until more information is available.
Interactions with Foods and Other Compounds
Food
Taking piroxicam with a meal may delay the speed, but not the overall amount, of drug absorption.6 Therefore, it may be taken with food if stomach upset occurs when taking the drug on an empty stomach.
References
1. Miller KP, Lazar EJ, Fotino S. Severe hyperkalemia during piroxicam therapy. Arch Int Med 1984;144:2414–5.
2. Baggott JE, Morgan SL, Ha T, et al. Inhibition of folate-dependent enzymes by non-steroidal anti-inflammatory drugs. Biochem J 1992;282:197–202.
3. Alter HJ, Zvaifler NJ, Rath CE. Interrelationship of rheumatoid arthritis, folic acid, and aspirin. Blood 1971;38:405–16.
4. Sifton DW, ed. Physicians Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 2342–4.
5. Sifton DW, ed. Physicians Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 2342–4.
6. Sifton DW, ed. Physicians Desk Reference. Montvale, NJ: Medical Economics Company, Inc., 2000, 2342–4.
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2006-09-07
