Side Effects

Drug information provided by: Merative, Micromedex®

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

  1. Cough
  2. fever or chills (continuing or severe)
  3. general feeling of discomfort, illness or weakness
  4. hoarseness
  5. mouth sores
  6. pain, swelling, or redness in joints
  7. throat infection


  1. Yellow eyes or skin

Check with your doctor as soon as possible if any of the following side effects occur:

More common

  1. Fever (mild and temporary)
  2. skin rash or itching


  1. Backache
  2. black, tarry stools
  3. blood in urine or stools
  4. increase in bleeding or bruising
  5. increase or decrease in urination
  6. numbness or tingling of fingers, toes, or face
  7. pinpoint red spots on skin
  8. shortness of breath
  9. swelling of feet or lower legs
  10. swollen lymph nodes
  11. swollen salivary glands

Symptoms of overdose

  1. Changes in menstrual periods
  2. coldness
  3. constipation
  4. dry, puffy skin
  5. headache
  6. listlessness or sleepiness
  7. muscle aches
  8. swelling in the front of the neck
  9. unusual tiredness or weakness
  10. weight gain (unusual)

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  1. Dizziness
  2. loss of taste (for methimazole)
  3. nausea
  4. stomach pain
  5. vomiting

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.