Tapazole (methimazole) Dosage and Side Effects
TAPAZOLE is used to treat an overactive thyroid known as hyperthyroidism. TAPAZOLE belongs to a group of drugs known as anti-thyroid agents. It works by interfering with the production of thyroid hormones — an action that decreases levels of these hormones in the body.
Warnings and Precautions
Don't take TAPAZOLE if you're allergic to the drug or any of its ingredients.
Women should avoid taking TAPAZOLE while breastfeeding.
Talk to your doctor before taking TAPAZOLE if you:
- Are pregnant
- Have low counts of red blood cells, white blood cells, or platelets
- Are taking Clozaril (clozapine) or Propyl-Thyracil (propylthiouracil, or PTU)
- Are receiving radiation treatment
Pregnancy and TAPAZOLE
Studies show that TAPAZOLE may cause birth defects.
Manufacturers of the drug state that it's not safe to take during pregnancy.
But your doctor may feel that the benefits of taking the drug during pregnancy outweigh the risks in certain situations.
TAPAZOLE is passed into breast milk, and its safety for nursing babies has been a topic of debate. Talk to your doctor before taking the drug while breastfeeding.
It's always a good idea to talk to your doctor about all medications you're taking if you're pregnant, planning a pregnancy, or breastfeeding.
TAPAZOLE for Cats
Veterinarians prescribe TAPAZOLE for overactive thyroids in cats, and treatment success rates are as high as 95 percent in cats.
Your veterinarian may ask you to give your cat TAPAZOLE twice a day for up to a year.
TAPAZOLE for cats comes in pill and liquid forms, and as a paste that you apply to the inside of your cat's outer ear.
Common Side Effects
Tell your doctor if any of the following side effects are severe or don't go away:
- Itching, hives, or a rash
- Darkening of the skin or jaundice (yellowing of the skin, nails, and whites of the eyes)
- Nausea and vomiting
- Altered taste and heartburn
- Headache, drowsiness, or dizziness
- Joint pain, inflamed nerves, and swelling
- Swelling of lymph nodes or salivary glands
Serious Side Effects
The following serious side effects require urgent medical attention:
- Low platelet, white blood cell, or red blood cell count
- Lack of new blood cell production by bone marrow
- Liver damage
- Kidney infection or inflammation
- Poor or slow blood clotting
- Inflammation of the lining of the arteries
Interactions with this medication
Tell your doctor(s) and pharmacist about all prescription, over-the-counter, illegal, recreational, herbal, nutritional, or vitamin-containing drugs and supplements you're taking.
Fortunately, TAPAZOLE doesn't interact with many drugs.
But talk to your doctor or pharmacist about TAPAZOLE if you're taking Coumadin or Jantoven (warfarin).
You may need to get your blood tested, or your warfarin dose adjusted, when you start taking TAPAZOLE.
Also, be careful with TAPAZOLE if you're taking herbal supplements like kava or black cohosh.
TAPAZOLE and Alcohol
Try to avoid or limit drinking alcohol while taking TAPAZOLE.
TAPAZOLE and Grapefruit Juice
Avoid eating grapefruit and drinking grapefruit juice while taking TAPAZOLE.
Grapefruit slows down the body's breakdown of TAPAZOLE, which could result in dangerously high levels of the drug in the bloodstream.
Proper Use of this medication
Always take TAPAZOLE with food. Don't take more than your doctor tells you to take.
If you suspect an overdose of TAPAZOLE, contact an emergency room or poison control center right away.
Missed Dose of TAPAZOLE
If you miss a dose of TAPAZOLE, take it as soon as you remember.
But if it's almost time for your next dose, skip the missed dose and take your next dose at the regular time.
Don't double up on doses to make up for a missed one.
Other related products
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.