Action

Unknown. Thought to inhibit cyclo-oxygenase, an enzyme needed for prostaglandin synthesis.

Availability

Capsules: 25 mg, 50 mg

Capsules (sustained-release): 75 mg

Oral suspension: 25 mg/5 ml

Indications and dosages

➣ Rheumatoid arthritis; osteoarthritis; ankylosing spondylitis

Adults: 25 to 50 mg P.O. two or three times daily, not to exceed 200 mg daily; or one 75-mg sustained-release capsule P.O. once or twice daily

➣ Acute gouty arthritis

Adults: 50 mg P.O. t.i.d. until pain is tolerable; then reduce dosage rapidly and, finally, discontinue drug. Don't give sustained-release form.

➣ Acute bursitis or tendinitis of shoulder

Adults: 75 to 150 mg P.O. daily in three or four divided doses. Discontinue once inflammation is controlled.

Off-label uses

• Bartter's syndrome

• Pericarditis

Contraindications

• Hypersensitivity to drug, its components, or other NSAIDs

• Active GI bleeding

• Concurrent diflunisal use

Precautions

Use cautiously in:

• severe cardiovascular, renal, or hepatic disease

• history of ulcer disease

• elderly patients

• pregnant or breastfeeding patients

• children ages 14 and younger (efficacy not established).

Administration

• Give with food, full glass of water, or antacids to reduce GI upset.

• Don't open or crush capsules.

• For arthritis, give up to 100 mg of daily dose at bedtime as needed to reduce nighttime pain and morning stiffness.

• Don't give sustained-release form to patients with gouty arthritis.

Adverse reactions

CNS: headache, dizziness, drowsiness, fatigue, vertigo, depression, seizures

EENT: tinnitus

GI: nausea, vomiting, diarrhea, constipation, abdominal pain or cramps, dyspepsia, ulcers, GI bleeding

Other: allergic reactions including anaphylaxis

Interactions

Drug-drug. Antihypertensives, diuretics: decreased efficacy of these drugs

Corticosteroids, other NSAIDs: additive adverse GI reactions

Cyclosporine: increased risk of nephrotoxicity

Diflunisal: potentially fatal GI hemorrhage

Lithium, methotrexate, zidovudine: increased risk of toxicity from these drugs

Probenecid: increased risk of indomethacin toxicity

Drug-diagnostic tests. Dexamethasone suppression test: false-negative result

Drug-herbs. Anise, arnica, chamomile, clove, dong quai, feverfew, garlic, ginger, ginkgo, ginseng: increased bleeding risk

Patient monitoring

• Assess for dizziness, drowsiness, headache, fatigue, and exacerbation of depression, epilepsy, or parkinsonism.

• Monitor for drug efficacy, indicated by improved joint mobility, pain relief, and decreased inflammation.

• Monitor urine output for marked reduction.

• Watch for signs and symptoms of GI bleeding and ulcers.

Patient teaching

• Tell patient to take with food, full glass of water, or antacid to reduce GI upset.

• Advise patient not to open or crush capsules.

• Inform breastfeeding patient that indomethacin enters breast milk and may cause seizures in infant. Advise her to use a different infant feeding method during therapy.

• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, balance, and alertness.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.