How NSAIDs Work

NSAIDs work by blocking enzymes known as cyclooxygenase (also known as COX). COX-1 and COX-2 are two very closely related variants of this enzyme.

In the study of genetics, COX is officially referred to by the long name prostaglandin-endoperoxide synthase (PTGS).

COX enzymes are used in the body to produce chemicals that cause the swelling and pain of arthritis. By blocking the COX enzymes, NSAIDs can reduce swelling and pain, and increase day-to-day function in arthritis patients.

Side Effects of NSAIDs

In general, NSAIDs are fairly well tolerated by patients.

We have put together a special guide to help patients learn more about the relative risks of taking NSAIDs compared to common lifestyle risk factors like smoking: NSAIDs & Osteoarthritis: Putting Risks Into Perspective.

MORE COMMON side-effects include:

  • Bloating, nausea, stomach pain, and heartburn.
  • Diarrhea or constipation

RARE side-effects include:

  • Allergic reactions such as skin rashes or wheezing
  • Headaches, dizziness, or ringing in the ears (tinnitus)
  • Unusual bruising or bleeding
  • Gastrointestinal Problems – NSAIDs can cause irritation to the lining of the stomach, esophagus, and intestine. Patients should notify their doctor if they experience any of the following:
    • Any stomach pain, nausea, or vomiting
    • Heartburn or indigestion
    • Black or bloody stools
    • Vomiting blood or “coffee ground” material
  • Fluid Retention – In some patients NSAIDs can cause fluid retention with swelling of the ankles and legs. They can also worsen a condition called congestive heart failure (CHF). Patients should tell your doctor if you have CHF or if they develop leg swelling.
  • Increase in Blood Pressure – Patients’ blood pressure should be monitored periodically by a doctor while taking NSAIDs, specially if they have high blood pressure.
  • Heart attack and stroke – Patients who have had a recent heart attack or stroke or experienced serious chest pain from heart disease should not take NSAIDs.
  • Allergic rash – NSAIDs can rarely cause an allergic rash. Patients should stop the medicine and tell their doctor if they develop a rash, hives, or blisters.

Patients should talk to their doctor if they are concerned about any side effects.

NSAIDs can simply be stopped and do not need to be “weaned off” like some other medications.

Who Should NOT Take NSAIDs

People that should NOT be taking NSAIDs include:

  • Those with asthma that is made worse when taking Aspirin (ASA)
  • Patients who have had a recent ulcer in the stomach or small bowel
  • Patients who have kidney or liver disease should use with caution and talk to their doctor
  • Patients who have significant congestive heart failure
  • Patients who have had a recent heart attack, stroke, or experienced serious chest pain related to heart disease should avoid NSAIDs and COXIBs

Certain groups of people that need to be careful while taking NSAIDs include:

  • Elderly patients (over age 65)
  • Patients who have had a previous stomach ulcer
  • Patients who are taking blood thinners such as warfarin (Coumadin)
  • Patients who have significant risk factors for heart attack or stroke should be aware that using NSAIDs and COXIBs may increase this risk. These patients and anyone who lives with them are advised to learn how to identify the signs of heart attack and stroke.

When to Call a Doctor

Patients taking NSAIDs should call their doctor if they feel sick and want to stop, or if they are concerned about any side effects.

Other reasons to call a doctor while taking NSAIDs include:

  • Rash
  • Severe leg swelling
  • Shortness of breath or chest pain
  • Stomach pain, nausea, vomiting, black or bloody stools
  • Allergic reaction

NSAIDs Video

Watch Dr. Andy Thompson, a Canadian rheumatologist, introduce NSAIDs.