Side Effects of Pain Medicines

All medicines have side effects. But many side effects can be managed so that you can still take the medicine. Talk to your doctor if you have any side effects. Your doctor may change your dose or the type of medicine you take.

Examples of side effects of over-the-counter medicines

• Acetaminophen (Tylenol)

  This medicine may cause:

  • Nausea.
  • Rash.
  • Liver damage (with high doses).
• Nonsteroidal anti-inflammatory drugs (such as Advil, Motrin, and Aleve)

  These may cause:

  • Stomach upset, heartburn, and nausea. Taking the medicine with food may help prevent these problems.
  • Stomach ulcers and kidney problems (with long-term use).
  • Allergic reaction (rare).
  • Increased risk of heart attack and stroke. These risks are greater if the medicine is taken at higher doses or for longer than recommended.

  No one younger than 20 should take aspirin. It has been linked to Reye syndrome, a serious illness.

Examples of side effects of prescription medicines

• Anticonvulsant medicines

  These may cause:

  • Dizziness.
  • Drowsiness.
  • Fatigue.
  • Headache.
  • Confusion.
  • Skin rash.

• Corticosteroids

  These may cause:

  • Nausea and vomiting.
  • Swelling of hands and feet.
  • Increased appetite.
  • Increased risk of infection.
  • Osteoporosis (with long-term use).
  • Cataracts (with long-term use).

  Because of the chance of side effects, doctors usually try to prescribe steroid medicines only for a short time.

• Opiate pain relievers

  These may cause:

  • Constipation.
  • Dizziness, lightheadedness, or feeling faint.
  • Drowsiness.
  • Nausea or vomiting.

If you take opiate pain relievers for longer than a week or so, they can cause your body to keep expecting the medicine. This is called drug dependency. This is not the same as addiction.

Addiction is a behavioral problem that happens when a person has a craving for the drug. This craving may not even be related to the level of pain. But opiate pain relievers rarely cause addiction when they are used under a doctor's care. Talk to your doctor if you are worried about addiction.

• Tricyclic and tetracyclic antidepressants

  These may cause:

  • Blurred vision.
  • Confusion.
  • Constipation.
  • Drowsiness and fatigue.
  • Dry mouth.
  • Loss of sexual desire or ability.

• Serotonin and norepinephrine reuptake inhibitor (SNRI) antidepressants

  These may cause:

  • Constipation.
  • Cough.
  • Dizziness.
  • Dry mouth.
  • Headache.
  • Nausea and loss of appetite.
  • Decrease in sexual desire or ability.
  • Sleep problems.
  • Weight loss.

• Selective serotonin reuptake inhibitor (SSRI) antidepressants

  These may cause:

  • Nausea.
  • Loss of appetite.
  • Diarrhea.
  • Anxiety.
  • Sleep problems.
  • Loss of sexual desire or ability.
  • Headaches.
  • Weight gain.

The U.S. Food and Drug Administration (FDA) has issued an advisory on antidepressant medicines and the risk of suicide. The FDA does not recommend that people stop using these medicines. Instead, a person taking antidepressants should be watched for warning signs of suicide. This is especially important at the beginning of treatment or when the doses are changed.

For more information, see the topic Dealing With Medicine Side Effects and Interactions.