NSAIDs are most effective for mild to moderate pain accompanied by swelling and inflammation. These drugs relieve pain by inhibiting an enzyme in your body called cyclooxygenase. This enzyme makes hormone-like substances called prostaglandins, which are involved in the development of pain and inflammation. NSAIDs are especially helpful for arthritis and pain resulting from muscle sprains, strains, back and neck injuries or cramps.

When taken as directed, NSAIDs are generally safe. But if more than the recommended dosage is taken — and sometimes even the recommended dosage — NSAIDs may cause nausea, stomach pain, stomach bleeding or ulcers. Large doses of NSAIDs can lead to kidney problems and fluid retention. Risk increases with age. If you regularly take NSAIDs, talk to your doctor so that he or she can monitor you for side effects.

NSAIDs have a so-called ceiling effect, or limit to how much pain they can control. This means that beyond a certain dosage, they don't provide additional benefit. If someone has moderate to severe pain, exceeding the dosage limit may not help relieve the pain.

Many NSAIDs require a prescription, but some lower-dose NSAIDs, such as aspirin and ibuprofen, are available over-the-counter.

Nabumetone (Relafen)

This drug is used to relieve pain, tenderness, swelling, and stiffness caused by osteoarthritis (arthritis caused by a breakdown of the lining of the joints) and rheumatoid arthritis (arthritis caused by swelling of the lining of the joints). Nabumetone comes as a tablet to take by mouth. It is usually taken once or twice a day with or without food. Take nabumetone at around the same time(s) every day.

Side effects.

Tell your doctor if any of these symptoms are severe or do not go away:

• diarrhea

• constipation

• gas or bloating

• dizziness

• headache

• dry mouth

• sores in the mouth

• nervousness

• difficulty falling asleep or staying asleep

• increased sweating

• ringing in the ears