The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.
Common Side Effects
Up to 10% of people taking this medication have reported the following side effects:
- Raised, itchy rash
- Nausea
- Vomiting
- Stomach upset
Less Common Side Effects
- Loss of taste
- Unusual hair loss
- Drowsiness
- Vertigo (feeling like your surroundings are spinning)
- Headache
- Muscle pain
- Joint pain
Methimazole serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Low white blood cells (agranulocytosis): fever, fatigue, chills, sore throat
- Inflamed blood vessels (vasculitis): rash, nerve pain, chest pain, stomach pain
- Unusual bleeding or bruising: black stools, blood in urine, bleeding or bruising that doesn’t go away
- Liver problems: upper right stomach pain, loss of appetite, yellowing of skin or whites of eyes (jaundice)
Source: DailyMed
The following Methimazole side effects have also been reported
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:
Incidence not known
Black, tarry stools
bleeding gums
bleeding under the skin
bloody or cloudy urine
burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
chills
dark urine
difficulty in breathing
dizziness or lightheadedness
drowsiness
feeling of constant movement of self or surroundings
general feeling of discomfort, illness, or weakness
headache
hoarseness
itching, skin rash
light-colored stools
loss of appetite and weight
loss of consciousness
lower back or side pain
painful or difficult urination
pinpoint red spots on the skin
redness, soreness, or itching skin
sensation of spinning
soreness of the muscles
sores, ulcers, or white spots on the lips or in the mouth
sores, welts, or blisters
stomach pain
swelling of the face, feet, or lower legs
swollen or painful glands
swollen salivary glands
swollen, painful, or tender lymph glands in the neck, armpit, or groin
tightness in the chest
unusual bleeding or bruising
unusual tiredness or weakness
unusual weight gain
upper right abdominal pain
yellow eyes or skin
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:
Incidence not known
Abnormal loss of hair
changes in skin coloring
difficulty in moving
joint pain or swelling
loss of taste
muscle pain, cramps, or stiffness
pain or discomfort in the chest, upper stomach, or throat
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.
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