Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes Tapazole (Methimazole). If you are concerned about side effects, discuss the risks and benefits of Tapazole (Methimazole) with your doctor.

The following side effects have been reported by at least 1% of people taking Tapazole (Methimazole). Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• change in skin colour
• dizziness
• drowsiness
• hair loss
• headache
• heartburn
• loss of appetite
• loss of taste sensation
• nausea
• skin rash or itching
• stomach pain
• vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

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

• kidney inflammation (e.g., backache, decreased urine, cloudy or bloody urine)
• lupus-like symptoms (e.g., Fever, general feeling of being unwell, joint pain, confusion, muscle aches, skin rash)
• muscle or joint pain
• numbness or tingling of fingers, toes, or face
• pinpoint-sized red spots on skin
• shortness of breath
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
• swelling of feet or lower legs
• swollen lymph nodes
• swollen salivary glands
• symptoms of liver damage (e.g., yellow skin or eyes, abdominal pain, dark urine, clay-coloured stools, loss of appetite, nausea and vomiting, or itching)
• symptoms of low blood sugar (e.g., cold sweat, cool pale skin, headache, fast heartbeat, weakness)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• increased frequency of infections (fever or chills, severe Diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• severe skin rash
• signs of pancreatitis (e.g., abdominal pain on the upper left side, back pain, nausea, fever, chills, rapid heartbeat, swollen abdomen)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Tapazole (Methimazole).