Methimazole is present in breast milk. However, several studies found no effect on clinical status in nursing infants of mothers taking methimazole. A long-term study of 139 thyrotoxic lactating mothers and their infants failed to demonstrate toxicity in infants who are nursed by mothers receiving treatment with methimazole. Monitor thyroid function at frequent (weekly or biweekly) intervals.
Because of postmarketing reports of severe liver injury in pediatric patient treated with propylthiouracil, methimazole is the preferred choice when an antithyroid drug is required for a pediatric patient (see DOSAGE AND ADMINISTRATION).
Major adverse reactions (which occur with much less frequency than the minor adverse reactions) include inhibition of myelopoiesis (agranulocytosis, granulocytopenia, thrombocytopenia, and 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. There have been postmarketing case reports of acute pancreatitis.
There are reports of a vasculitis, often associated with the presence of anti-neutrophilic cytoplasmic antibodies (ANCA), resulting in severe complications (see WARNINGS).
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.
Symptoms may include nausea, vomiting, epigastric distress, headache, fever, joint pain, pruritus, and edema. Aplastic anemia (pancytopenia) or agranulocytosis may be manifested in hours to days. Less frequent events are hepatitis, nephrotic syndrome, exfoliative dermatitis, neuropathies, and CNS stimulation or depression. No information is available on the median lethal dose of the drug or the concentration of methimazole in biologic fluids associated with toxicity and/or death.
To obtain up-to-date information about the treatment of overdose, a good resource is your certified Regional Poison Control Center. In managing overdosage, consider the possibility of multiple drug overdoses, interaction among drugs, and unusual drug kinetics in the patient.
In the event of an overdose, appropriate supportive treatment should be initiated as dictated by the patient’s medical status.
Adult — The initial daily dosage is 15 mg for mild hyperthyroidism, 30 to 40 mg for moderately severe hyperthyroidism, and 60 mg for severe hyperthyroidism, divided into 3 doses at 8-hour intervals. The maintenance dosage is 5 to 15 mg daily.
Pediatric — Initially, the daily dosage is 0.4 mg/kg of body weight divided into 3 doses and given at 8-hour intervals. The maintenance dosage is approximately 1/2 of the initial dose.
Methimazole tablets, USP 5 mg — round, white to off white bi-convex tablet. Debossed HP bisect 70 on one side and plain on the reverse side.
They are available in:
Bottles of 100 NDC 60429-380-01
Methimazole tablets, USP 10 mg — round, white to off white bi-convex tablet. Debossed HP bisect 71 on one side and plain on the reverse side.
They are available in:
Bottles of 100 NDC 60429-381-01
Bottles of 1000 NDC 60429-381-10 DISCONTINUED
Store at 20° to 25°C (68° to 77°F); excursions permitted between 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature].
Dispense in tight, light-resistant container.
Avet Pharmaceuticals Inc.
East Brunswick, NJ 08816
Camarillo, CA USA 93012
Methimazole 5mg Tablets 100
Methimazole 10mg Tablets 1000
| METHIMAZOLE |
| METHIMAZOLE |
|Labeler — Golden State Medical Supply (603184490)|
|Golden State Medical Supply||603184490||relabel (60429-380), repack (60429-380), relabel (60429-381), repack (60429-381)|
Revised: 08/2020 Golden State Medical Supply
All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.