Patient Medication Information: uses, side effects, how to take - Mar-Methimazole
What is MAR-METHIMAZOLE used for?
Mar-Methimazole is used in adults:
- to treat hyperthyroidism (overactive thyroid gland).
- to treat and prepare for thyroidectomy (removal of the thyroid gland) or for radioactive iodine treatment.
- when the overactive thyroid gland cannot be removed.
How does MAR-METHIMAZOLE work?
Mar-Methimazole is a type of medication called antithyroid agents. It works by stopping the thyroid gland from making thyroid hormones.
What are the ingredients in MAR-METHIMAZOLE?
Medicinal ingredient: Methimazole
Non-medicinal ingredients: Lactose monohydrate, magnesium stearate, starch and talc.
MAR-METHIMAZOLE comes in the following dosage forms:
Tablets: 5 mg and 10 mg
Do not use MAR-METHIMAZOLE if:
- you are allergic to methimazole or any of the ingredients in Mar-Methimazole.
- you are breastfeeding. Mar-Methimazole can be transferred into your breast milk.
- you have or have had problems with your pancreas after taking methimazole.
Serious Warnings and Precautions
- Agranulocytosis (decrease in white blood cell count): Treatment with Mar-Methimazole can cause agranulocytosis. Your healthcare professional will monitor your health for signs and symptoms of agranulocytosis.
- Liver toxicity (injury or damage to the liver): Treatment with Mar-Methimazole can cause liver toxicity problems. This can lead to fulminant hepatitis (inflammation of the liver), hepatic necrosis (death of liver cells), encephalopathy (a neurological disorder), and cholestatic jaundice (yellowing of the skin or whites of eyes). If you notice any signs and symptoms of liver toxicity, tell your healthcare professional, they will also monitor your liver function.
See the Serious side effects and what to do about them table, below, for more information on these and other serious side effects.
To help avoid side effects and ensure proper use, talk to your healthcare professional before you take Mar-Methimazole. Talk about any health conditions or problems you may have, including if you:
- have a low white blood cell count.
- have joint pain.
- have liver problems.
- have skin problems.
- are intolerant to some sugars (e.g., lactose, a milk sugar which is a component of Mar-Methimazole).
- have a large goitre (swelling in the front neck), the goitre may grow during treatment making it difficult to breath.
- are taking medications that are known to cause agranulocytosis (decrease in white blood cell count).
Other warnings you should know about:
Mar-Methimazole can cause the following:
- Arthralgia (joint pain): The development of arthralgia may indicate severe transient migratory polyarthritis also known as antithyroid arthritis syndrome (pain that spreads from one joint to another). Your healthcare professional will stop your treatment if this occurs.
- Acute pancreatitis (inflammation of the pancreas): Mar-Methimazole therapy has been reported to cause acute pancreatitis. If you notice any signs and symptoms of acute pancreatitis, your healthcare professional will immediately stop your treatment with methimazole.
- Exfoliative dermatitis (severe inflammation of the entire skin surface): Tell your healthcare professional right away if you notice signs of exfoliative dermatitis such as redness or peeling of the skin over large areas of your body. Your treatment with Mar-Methimazole should be stopped.
- Vasculitis (inflammation and narrowing of blood vessels): This can cause long-term organ damage or even be life-threatening. Tell your healthcare professional if you notice or develop any symptoms of vasculitis. They will stop your treatment and may initiate an appropriate intervention.
Other blood problems: Mar-Methimazole therapy can cause:
- leukopenia (low white blood cells),
- thrombocytopenia (low blood platelets), and
- aplastic anemia (when cells meant to develop into mature blood cells are damaged).
Your healthcare professional may monitor your health (including your bone marrow function) and may stop your treatment if this occurs.
See the Serious side effects and what to do about them table, below, for more information on these and other serious side effects.
Pregnancy:
- If you are able to get pregnant or think you are pregnant, there are specific risks you must discuss with your healthcare professional.
- Treatment with Mar-Methimazole may harm your unborn baby, especially in the first trimester of pregnancy. Your healthcare professional will decide if taking Mar-Methimazole is right for you and your baby.
- You should use effective methods of birth control during your treatment.
- If you become pregnant or think you are pregnant while taking Mar-Methimazole, tell your healthcare professional right away.
Check-ups and testing: Your healthcare professional will monitor your health before and during your treatment. This may include having regular blood tests. This will tell your healthcare professional how Mar-Methimazole is affecting you.
Driving and using machines: MAR-METHIMAZOLE can cause tiredness and a sense of spinning dizziness. Before you drive or do tasks that require special attention, wait until you know how you respond to MAR-METHIMAZOLE.
Tell your healthcare professional about all the medicines you take, including any drugs, vitamins, minerals, natural supplements or alternative medicines.
The following may interact with Mar-Methimazole:
- medicines known as anticoagulants (blood thinners) such as warfarin.
How to take MAR-METHIMAZOLE:
- Take Mar-Methimazole exactly as prescribed by your doctor.
- Mar-Methimazole is usually taken orally three times a day (every 8 hours).
- Patients should wash their hands with soap and water after handling the tablet, particularly if they have to break the tablet.
- Mar-Methimazole should not be handled by pregnant women and children.
Usual Dose:
The initial dose is 15 mg to 60 mg per day depending on your condition. The maintenance dose is 5 mg to 15 mg per day.
Overdose:
If you take too many Mar-Methimazole tablets, you may experience:
|
|
|
|
|
|
|
|
Missed Dose:
Talk to your healthcare professional if you miss one of your scheduled doses of Mar-Methimazole. You should not take a double dose to make up for a forgotten dose. Take your next scheduled dose as usual.
What are possible side effects from using Mar-Methimazole?
These are not all the possible side effects you may have when taking Mar-Methimazole. If you experience any side effects not listed here, tell your healthcare professional.
Some common side effects include:
|
|
|
|
|
|
|
|
If you think you, or a person you are caring for, have taken too much Mar-Methimazole, contact a healthcare professional, hospital emergency department, or regional poison control centre immediately, even if there are no symptoms.
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help | |
|---|---|---|---|
| Only if severe | In all cases | ||
| UNCOMMON | |||
| Agranulocytosis (decrease in white blood cell count): frequent infection with fever, chills, sore throat. | ✓ | ||
| Liver problems (including hepatitis): abdominal pain, yellowing of your skin and eyes (jaundice), right upper stomach area pain or swelling, nausea, vomiting, unusual dark urine, unusual tiredness. | ✓ | ||
| RARE | |||
| Aplastic anemia (when cells meant to develop into mature blood cells are damaged): fatigue, weakness, pale skin, fevers, frequent infection, tendency to bruise and bleed easily. | ✓ | ||
Drug fever: fever greater than 40.5°C (105˚F). | ✓ | ||
| Nephritis (inflammation of the kidney): decreased appetite, difficulty breathing, fatigue, frequent urination, itchiness, nausea, vomiting. | ✓ | ||
| VERY RARE | |||
| Vasculitis (inflammation of blood vessels): fever, headache, fatigue, weight loss, night sweats, rash, blood in urine, coughing up blood, shortness of breath. | ✓ | ||
| UNKNOWN | |||
| Acute pancreatitis (inflammation of the pancreas): upper abdominal pain, severe stomach pain that last and gets worse when you lie down, rapid heart beat, fever, nausea, vomiting. | ✓ | ||
| Arthralgia (joint pain). | ✓ | ||
| Exfoliative dermatitis (severe inflammation of the entire skin surface): redness or peeling of the skin over large areas of your body. | ✓ | ||
| Hypoprothrombinemia (abnormally low levels of prothrombin, used for blood- clotting): bleeding problems, easy bruising. | ✓ | ||
| Hypothyroidism (underactive/low thyroid): Weight gain, tiredness, hair loss, muscle weakness, feeling cold, dry skin, constipation, puffy face, heavier than | ✓ | ||
Serious side effects and what to do about them
| Symptom / effect | Talk to your healthcare professional | Stop taking drug and get immediate medical help | |
|---|---|---|---|
| Only if severe | In all cases | ||
| normal or irregular menstrual periods, enlarged thyroid gland. | |||
| Insulin autoimmune syndrome (an immune response against your body’s own cells that causes low blood sugar): numbness in the extremities, low levels of blood sugar. | ✓ | ||
| Lupus-like syndrome (when your body’s immune system attacks your own tissues and organs, including your joints, skin, kidneys, blood cells, heart and lungs): fatigue, fever, joint pain, stiffness and swelling, rash on the face that covers the cheeks and the bridge of the nose or rashes elsewhere on the body, skin lesions, shortness of breath, chest pain, dry eyes, headaches, confusion, memory loss. | ✓ | ||
| Periarteritis (inflammation of the tissue surrounding an artery): pain in the muscles and joints. | ✓ | ||
If you have a troublesome symptom or side effect that is not listed here or becomes bad enough interfere with your daily activities, tell your healthcare professional.
Storage:
Store at room temperature (15 °C to 30 °C). Protect from light. Keep the bottle tightly closed. Keep out of reach and sight of children.
If you want more information about MAR-METHIMAZOLE:
- Talk to your healthcare professional
- Find the full product monograph that is prepared for healthcare professionals and includes this Patient Medication Information by visiting the Health Canada website: (https://www.canada.ca/en/health-canada/services/drugs-health-products/drug-products/drug- product-database.html); Marcan Pharmaceuticals Inc.’s website www.marcanpharma.com, or by calling 1-855-627-2261.
Last Revised: October 10, 2023
Reporting Side Effects
You can report any suspected side effects associated with the use of health products to Health Canada by:
- Visiting the Web page on Adverse Reaction Reporting (https://www.canada.ca/en/health- canada/services/drugs-health-products/medeffect-canada/adverse-reaction-reporting.html) for information on how to report online, by mail or by fax; or
- Calling toll-free at 1-866-234-2345.
NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.