How Do NSAIDs Work?

Reviewed on 9/21/2021

How do NSAIDs work?

NSAIDs are non-steroidal anti-inflammatory drugs prescribed to treat inflammation and associated symptoms. NSAIDs reduce inflammation, bring down fever, and relieve pain. NSAIDs also reduce blood clotting time, and some NSAIDs such as aspirin are protective against heart disease.

NSAIDs control inflammation by inhibiting the activity of enzymes known as cyclooxygenases (COX-1 and COX-2), essential for the biosynthesis of prostaglandin. Prostaglandin is a fatty compound that promotes inflammation, which results in pain, fever, and other symptoms.

COX-1 produces prostaglandins which have many functions that include initiating inflammation, protecting the stomach lining from stomach acids, maintaining kidney function, and regulating blood clotting. COX-2 produces prostaglandins when joints are injured.

Traditional NSAIDs inhibit both COX-1 and COX-2, but COX-2 inhibitors are a category of NSAIDs that inhibit only COX-2 activity. Both types of COX inhibitors provide pain relief (analgesia), but COX-2 inhibitors do not usually cause NSAID side effects such as stomach upset or bleeding issues. COX-2 inhibitors also do not protect against heart disease.

How are NSAIDs used?

NSAIDs are available in several formulations, strengths, and forms which include the following:

  • Oral formulations such as tablets, capsules, and solutions
  • Periarticular installation in which NSAID is injected in combination with a local anesthetic for pain relief after certain surgical procedures
  • Rectal suppository inserted into the rectum
  • Intravenous (IV) injection
  • Intramuscular (IM) injection
  • An oral film that is applied inside the mouth
  • Intranasal medication that is sprayed into the nostrils

NSAIDs may be prescribed to treat acute or chronic pain, fever, and inflammation. NSAIDs are used to treat inflammation and pain in the following conditions:

Other conditions some of the NSAIDs are used to treat include:

  • Patent ductus arteriosus (PDA): A normal fetal connection between the aorta and pulmonary artery that persists abnormally in newborn babies. Intravenous NSAID closes the PDA by blocking the prostaglandins that keep the ductus arteriosus open and enable normal blood circulation. NSAIDs typically used include ibuprofen and indomethacin.
  • Familial adenomatous polyposis: An inherited genetic disorder that causes the growth of multiple polyps in the colon raising the risk for colorectal cancer. NSAIDs such as celecoxib, sulindac, and aspirin have been found to reduce the size and number of polyps.
  • Nephrogenic diabetes insipidus: An inherited genetic kidney disorder that causes excessive water loss due to the inability of the kidneys to reabsorb fluid. Indomethacin is used as an antidiuretic to reduce urine output.
  • Malignant glioma: Glioma is a type of brain or spinal tumor. Clinical trials show that etodolac may slow down tumor growth and has orphan designation to treat malignant glioma.
  • Cardiovascular conditions: Aspirin is commonly used to reduce the clotting action and improve blood flow in conditions with reduced blood flow to the heart. Low-dose aspirin may be prescribed as prophylaxis for people at high risk for cardiovascular diseases.
  • Ischemic stroke/transient ischemic stroke (TIA): Aspirin is used to improve blood flow after strokes caused by the reduced blood supply to the brain.

NSAIDs must be used with caution in people with kidney/liver impairment or gastrointestinal issues. Some NSAID formulations are combined with other drugs for specific reasons. The NSAID combinations include:


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What are side effects of NSAIDs?

Side effects of NSAIDs may include the following:

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

What are names of some NSAID drugs?

Generic and brand names of NSAID drugs include:


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