Understanding Indomethacin: A Potent NSAID
Indomethacin is a nonsteroidal anti-inflammatory drug (NSAID) prescribed to relieve moderate to severe pain, stiffness, and swelling [1.2.3]. It is used for various conditions, including several types of arthritis (rheumatoid, osteoarthritis, gouty), ankylosing spondylitis, and shoulder pain from bursitis or tendinitis [1.6.1]. It functions by inhibiting cyclooxygenase (COX) enzymes, which stops the body's production of prostaglandins—substances that cause pain, fever, and inflammation [1.6.1, 1.6.5]. While effective, indomethacin is considered one of the more potent NSAIDs and carries a significant risk of adverse effects [1.7.3].
The Major Side Effects: A Two-Pronged Risk
Indomethacin has two major categories of serious side effects that carry FDA warnings: gastrointestinal (GI) complications and cardiovascular events [1.2.3, 1.9.2].
1. Gastrointestinal (GI) Risks All NSAIDs can irritate the stomach lining, but indomethacin is associated with a higher risk of GI problems compared to some others like ibuprofen [1.7.3, 1.5.2].
- Ulcers and Bleeding: The most significant GI risk is the development of ulcers, bleeding, or perforations (holes) in the stomach or intestines. These events can occur at any time during treatment, may happen without any warning signs, and can be fatal [1.2.3, 1.9.4]. Symptoms to watch for include severe stomach pain, black or tarry stools, and vomit that looks like coffee grounds [1.2.1].
- Increased Risk Factors: The risk is higher for those who take NSAIDs for a long time, are older, have poor health, or consume significant amounts of alcohol [1.2.3]. A prior history of peptic ulcer disease increases the risk for a GI bleed by more than 10-fold [1.10.2].
2. Cardiovascular Risks NSAIDs, including indomethacin, may increase the risk of serious and potentially fatal cardiovascular thrombotic events like heart attack and stroke [1.2.2, 1.9.2].
- Increased Blood Pressure: Indomethacin can lead to the onset of new high blood pressure or worsen pre-existing hypertension [1.10.2].
- Heart Failure: The medication can cause fluid retention and edema (swelling), which can exacerbate or lead to heart failure [1.10.4].
- Contraindications: Due to these risks, indomethacin is contraindicated right before or after coronary artery bypass graft (CABG) surgery [1.9.1]. It should be avoided in patients who have had a recent heart attack unless the benefits are deemed to outweigh the risks by a doctor [1.9.2].
Other Serious and Common Side Effects
Beyond the primary GI and cardiovascular warnings, indomethacin can affect other body systems.
- Central Nervous System (CNS): Headache is a very common side effect, reported in up to 11.7% of patients [1.3.5]. Dizziness, drowsiness, confusion, and vertigo are also frequently reported [1.9.4, 1.3.3]. In older adults, indomethacin may cause confusion or, rarely, psychosis [1.10.2].
- Kidney (Renal) Effects: Long-term use can lead to renal injury, including renal papillary necrosis [1.10.2]. Patients at the greatest risk include the elderly and those with pre-existing impaired renal function, heart failure, or liver dysfunction [1.10.2].
- Liver (Hepatic) Effects: While rare, severe liver reactions, including jaundice and fatal hepatitis, have been reported [1.9.4]. Up to 15% of patients may experience borderline elevations in liver tests [1.9.4].
Comparison with Other NSAIDs
Not all NSAIDs carry the same level of risk. A comparison helps put indomethacin's side effect profile into perspective.
| Feature | Indomethacin | Ibuprofen |
|---|---|---|
| Potency | Considered one of the most potent NSAIDs [1.7.3] | Lower potency, often available over-the-counter [1.5.1] |
| GI Risk | Associated with an intermediate to high risk of GI complications [1.5.1, 1.5.2] | Associated with the lowest relative risk at typical doses [1.5.1] |
| Cardiovascular Risk | Considered to carry a high risk for cardiovascular side effects [1.7.3] | Risk is present, particularly at higher doses, but generally considered lower than indomethacin [1.5.1] |
| Common Uses | Moderate to severe arthritis, gout, ankylosing spondylitis [1.6.1] | Mild to moderate pain, fever, and inflammation |
How to Minimize Risks
If your doctor prescribes indomethacin, you can take steps to mitigate potential side effects:
- Use the Lowest Effective Dose: Always use the smallest dose needed to control your symptoms for the shortest possible duration [1.7.3, 1.10.2].
- Take with Food: Taking indomethacin with food, immediately after meals, or with antacids can help reduce stomach irritation [1.2.3, 1.7.2].
- Avoid Alcohol: Alcohol can worsen stomach irritation and increase the risk of bleeding [1.8.1].
- Inform Your Doctor: Disclose your full medical history, especially of any heart disease, high blood pressure, kidney or liver problems, or a history of stomach ulcers [1.2.3]. Provide a full list of all other medications you take, including over-the-counter drugs and supplements, to avoid harmful interactions [1.8.1].
Conclusion
The major side effects of indomethacin are serious gastrointestinal and cardiovascular events, including stomach bleeding, ulcers, heart attack, and stroke [1.2.2, 1.2.3]. While it is a potent and effective anti-inflammatory medication for specific conditions, its high-risk profile means it must be used with extreme caution. Patients should follow their doctor's instructions precisely, use the lowest effective dose for the shortest time, and immediately report any concerning symptoms such as severe abdominal pain, chest pain, shortness of breath, or black, tarry stools [1.2.1, 1.9.2].
Authoritative Link: For more detailed patient information, consult the MedlinePlus page on Indomethacin [1.2.3].
