Methimazole (Methimazole) - Side Effects and Adverse Reactions

ADVERSE REACTIONS

Major adverse reactions (which occur with much less frequency than the minor adverse reactions) include inhibition of myelopoiesis (agranulocytosis, granulocytopenia, and thrombocytopenia), aplastic anemia, drug fever, a lupus like syndrome, insulin autoimmune syndrome (which can result in hypoglycemic coma), hepatitis (jaundice may persist for several weeks after discontinuation of the drug), periarteritis, and hypoprothrombinemia. Nephritis occurs very rarely.

Minor adverse reactions include skin rash, urticaria, nausea, vomiting, epigastric distress, arthralgia, paresthesia, loss of taste, abnormal loss of hair, myalgia, headache, pruritus, drowsiness, neuritis, edema, vertigo, skin pigmentation, jaundice, sialadenopathy, and lymphadenopathy.

It should be noted that about 10% of patients with untreated hyperthyroidism have leukopenia (white-blood-cell count of less than 4,000/mm3), often with relative granulopenia.

REPORTS OF SUSPECTED METHIMAZOLE SIDE EFFECTS / ADVERSE REACTIONS

Possible Methimazole side effects / adverse reactions in 46 year old female

Reported by a consumer/non-health professional from United States on 2011-10-03

Patient: 46 year old female weighing 68.0 kg (149.7 pounds)

Reactions: Vomiting, Pruritus, Nausea, Chills, Chromaturia, Pyrexia, Headache, Somnolence, Abdominal Pain Upper, Arthralgia, Dizziness, Gait Disturbance, Asthenia, Decreased Appetite

Suspect drug(s):
Methimazole

Possible Methimazole side effects / adverse reactions in 44 year old female

Reported by a health professional (non-physician/pharmacist) from Taiwan, Province of China on 2011-10-05

Patient: 44 year old female

Reactions: Agranulocytosis, Impaired Healing, Blood Culture Positive, Pseudomonas Infection, Culture Throat Positive, Pyrexia, Oropharyngeal Pain, Hyperthyroidism, Leukopenia

Adverse event resulted in: hospitalization

Suspect drug(s):
Methimazole

Possible Methimazole side effects / adverse reactions in 53 year old male

Reported by a health professional (non-physician/pharmacist) from Netherlands on 2011-10-06

Patient: 53 year old male

Reactions: Blood Pressure Increased, Agranulocytosis, Malaise, Heart Rate Increased, Chills, Pyrexia, Pharyngeal Erythema

Adverse event resulted in: hospitalization

Suspect drug(s):
Methimazole

Other drugs received by patient: Levothyroxine Sodium