.
Piroxicam is used to treat rheumatoid arthritis and osteoarthritis. It is in a class of medications known as non-steroidal anti-inflammatory drugs (NSAIDs).
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.
Summary of Interactions for Piroxicam
| Depletion or interference | None known |
|---|---|
| Adverse interaction | Lithium* Potassium* |
| Side effect reduction/prevention | None known |
| Supportive interaction | None known |
| Reduced drug absorption/bioavailability | None known |
| Other (see text) | Folic acid* Willow* |
For the convenience of the reader, the information in the summary is categorized as follows: “Depletion or interference” indicates the drug may deplete or interfere with the absorption or function of the supplement or herb. “Adverse interaction” indicates that the supplement or herb used together with the drug may result in undesirable effects. “Side effect reduction/prevention” indicates the supplement or herb may reduce the likelihood and/or severity of a potential side effect caused by the drug. “Supportive interaction” indicates the supplement or herb may support or aid the function of the drug. “Reduced drug absorption/bioavailability” indicates that the supplement or herb may decrease the absorption and/or activity of the drug in the body. An asterisk (*) next to an item in the summary indicates that the interaction is supported only by weak, fragmentary, and/or contradictory scientific evidence.
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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The information presented in VitaminLore is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over-the-counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.