JAMP METHIMAZOLE

1 Dosing Considerations • JAMP Methimazole treatment can cause hypothyroidism and adjustments in dosing are necessary to maintain a euthyroid state (see Endocrine and Metabolism, Hypothyroidism). JAMP Methimazole (methimazole tablets) Product Monograph Page 5 of 22 Excess dosage should be avoided as it can lead to sub-clinical or clinical hypothyroidism and goitre growth (see Respiratory).

Periodic monitoring of thyroid function should be performed with dosage adjustments as necessary and with more careful monitoring in patients with large goitres (see Monitoring and Laboratory Tests). 4 Drug-Drug Interactions). • JAMP Methimazole can only be administered during pregnancy after a strict individual benefit/risk assessment and only at the lowest effective dose, without additional administration of thyroid hormones.

1 Pregnant Women). 2 Recommended Dose and Dosage Adjustment Adult (≥18 years of age): The initial daily dose is 15 mg for mild hyperthyroidism, 30 to 40 mg for moderately severe hyperthyroidism, and 60 mg for severe hyperthyroidism, divided into three doses at eight-hour intervals.

The maintenance dosage is 5 to 15 mg daily.

Geriatric (≥65 years of age):

Clinical studies of methimazole did not include sufficient numbers of subjects aged 65 or over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

3 Pediatrics).

Hepatic impairment:

The dose should be kept as low as possible, and patients should be closely monitored as the plasma clearance of methimazole is reduced (see Monitoring and Laboratory Tests).

Renal impairment:

The dose should be kept as low as possible and careful individual dose adjustment under close monitoring is recommended as there is a lack of data regarding the pharmacokinetic behaviour of methimazole in patients with renal impairment.

4 Administration • JAMP Methimazole is administered orally. • JAMP Methimazole is usually given in three equal doses per day at approximately eight-hour intervals. 5 Missed Dose JAMP Methimazole (methimazole tablets) Product Monograph Page 6 of 22 If a dose is missed, patients should contact their healthcare professional.

1 Adverse Reaction Overview Serious adverse reactions (which occur less frequently than the minor less serious 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. Cholestatic jaundice, fulminant hepatitis, encephalopathy, hepatic necrosis, and death have been rarely reported. See 7 WARNINGS AND PRECAUTIONS. Less serious 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, anorexia, JAMP Methimazole (methimazole tablets) Product Monograph Page 11 of 22 right upper-quadrant pain, and lymphadenopathy.

4 Abnormal Laboratory Findings: Hematologic, Clinical Chemistry and Other Quantitative Data Clinical Trial Findings It should be noted that about 10% of patients with untreated hyperthyroidism have leucopenia (white- blood-cell count of less than 4,000/mm3), often with relative granulopenia.

5 Post-Market Adverse Reactions The following adverse reactions have been reported from marketing experience with methimazole. Acute pancreatitis (see 7 WARNINGS AND PRECAUTIONS, Hepatic/Biliary/Pancreatic). Vasculitis (see 7 WARNINGS AND PRECAUTIONS, Cardiovascular).

1 Pregnant Women).

, Hepatic/Biliary/Pancreatic 09/2023 TABLE OF CONTENTS Sections or subsections that are not applicable at the time of authorization are not listed. 1 Pediatrics ...............................................................................................................

2 Geriatrics ............................................................................................................... 1 Dosing Considerations ...........................................................................................

2 Recommended Dose and Dosage Adjustment ....................................................... 4 Administration ....................................................................................................... 5 Missed Dose...........................................................................................................

1 Special Populations ................................................................................................ 1 Pregnant Women ...................................................................................................

2 Breast-feeding ..................................................................................................... 3 Pediatrics .............................................................................................................

4 Geriatrics ............................................................................................................. 10 8 ADVERSE REACTIONS .................................................................................................

1 Adverse Reaction Overview ................................................................................. 4 Abnormal Laboratory Findings: Hematologic, Clinical Chemistry and Other JAMP Methimazole (methimazole tablets) Product Monograph Page 3 of 22 Quantitative Data Clinical Trial Findings ..............................................................

Methimazole is contraindicated in: • Patients who are hypersensitive to this drug or to any ingredient in the formulation, including any non-medicinal ingredient, or component of the container. For a complete listing, see 6 Dosage Forms, Strengths, Composition and Packaging.

• Breastfeeding women, as the drug is excreted in breast milk. • Patients with history of acute pancreatitis after administration of methimazole.