Information about Matazor

Each tablet contains: 5 or 10 mg Methimazole.

Pharmacological properties:

Methimazole inhibits the synthesis of thyroid hormones and thus is effective in the treatment of hyperthyroidism. The drug does not inactivate existing thyroxine and triiodothyronine that are stored in the thyroid or circulating in the blood nor does it interfere with the effectiveness of thyroid hormones given by mouth or by injection.

Methimazole is readily absorbed in the gastrointestinal tract, metabolized inthe liver, and excreted in the urine.


Methimazoleis indicated:

In patients with Graves’ disease with hyperthyroidism ortoxic multinodular goiter for whom surgery or radioactive iodine therapy is not an appropriate treatment option.

To ameliorate symptoms of hyperthyroidism in preparationfor thyroidectomy or radioactive iodine therapy.


Methimazoleis contraindicated in the presence of hypersensitivity to the drug or any ofthe other product components.


First Trimester Use of Methimazoleand Congenital Malformations:

Methimazole crosses the placental membranes and can cause fetal harm when administered in the first trimester ofpregnancy. Rare instances of congenital defects have occurred in infants bornto mothers who received Methimazole in the first trimester of pregnancy. If Methimazole is used, the lowest possible dose to control the maternal disease should be given.


The drug should be discontinued inthe presence of agranulocytosis, aplastic anemia (pancytopenia),(ANCA)-positive vasculitis, hepatitis, or exfoliative dermatitis, and thepatient’s bone marrow indices should be monitored.

Liver Toxicity:

Drug treatment should bediscontinued promptly in the event of clinically significant evidence of liver abnormality including hepatic transaminase values exceeding 3 times the upper limit of normal.


Methimazole can cause hypothyroidism necessitating routine monitoring of TSH and free T4 levels with adjustments in dosing to maintain a euthyroid state.


Patients who receive Methimazole should be under close surveillance and should be cautioned to report immediately any evidence of illness, particularly sore throat, skin eruptions,fever, headache, or general malaise. In such cases, white-blood-cell and differential counts should be obtained to determine whether agranulocytosis has developed.Particular care should be exercised with patients who are receiving additional drugs known to cause agranulocytosis.

Informationfor Patients:

Patients should be advised that if they become pregnant or intend to become pregnant while taking an antithyroid drug, they should contact their physician immediately about their therapy.

Pregnancy,Category D:

If Methimazole is used during thefirst trimester of pregnancy or if the patient becomes pregnant while takingthis drug, the patient should be warned of the potential hazard to the fetus.

Due to the occurrence risk ofcongenital malformations associated with Methimazole use, it may be appropriateto use an alternative anti-thyroid medication in pregnant women requiring treatment for hyperthyroidism, particularly in the first trimester of pregnancy.


Methimazole is present in breast milk. Several studies found no effect on clinical status in nursing infants of mothers taking Methimazole.


Because of postmarketing reports of severe liver injury in pediatric patients treated with propylthiouracil, Methimazole is the preferred choice when an anti-thyroiddrug is required for a pediatric patient.


Because Methimazole may cause hypoprothrombinemia and bleeding, prothrombin time should be monitored during therapy, especially before surgical procedures. Thyroid function tests should be monitored periodically during therapy.

Drug interaction:

Oral Anticoagulants: Due to potential inhibition ofvitamin K activity by Methimazole, the activity of oral anticoagulants (e.g.,warfarin) may be increased; additional monitoring of PT/INR should be considered, especially before surgical procedures.

ß-adrenergic blocking agents: Hyperthyroidism may cause anincreased clearance of beta blockers. A dose reduction of beta-adrenergic blockers may be needed.

Digitalis glycosides: a reduced dosage of digitalis glycosides may be needed.

Theophylline: a reduced dose of theophylline may be needed.

Side effect:

Major adverse reactions:

include inhibitionof myelopoiesis (agranulocytosis, granulocytopenia, thrombocytopenia, andaplastic anemia), drug fever, a lupus-like syndrome, insulin autoimmune syndrome (which can result in hypoglycemic coma), hepatitis (jaundice may persist for severalweeks after discontinuation of the drug), periarteritis, andhypoprothrombinemia. Nephritis occurs very rarely.

Minor adverse reactions:

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

Dosage and Administration:

The total daily dosage is usually given in 3 divided doses at approximately 8-hour intervals.

Adults: The initial daily dosage is 15 mgfor 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 0.4mg/kg of body weight divided into 3 doses and given at 8-hour intervals.

Themaintenance dosage is approximately 1/2 of the initial dose.


Symptoms may include nausea,vomiting, epigastric distress, headache, fever, joint pain, pruritus, andedema. Aplastic anemia (pancytopenia) or agranulocytosis may be manifested inhours to days.

Treatment: In managing over dosage, considerthe possibility of multiple drug overdoses and interaction among drugs.In the event of an overdose, appropriate supportive treatment should beinitiated as dictated by the patient’s medical status.


Store at room temperature, 15° to 30°C.


Carton pack contains 30 tablets.