Carbimazole vs methimazole: why the milligrams differ
A different name and number on the box? Carbimazole becomes methimazole, but doses differ. What to check when changing medicine or moving abroad.
Neo-Mercazole: a guide to carbimazole
Neo-Mercazole is carbimazole, a medicine for an overactive thyroid. Find clear answers on what it does, doses, side effects and the next steps.
Start with the ingredient
What Neo-Mercazole is
Neo-Mercazole contains carbimazole, a prescription medicine that reduces new thyroid hormone production. It is used for an overactive thyroid, including Graves’ disease and toxic nodular goitre.
The box gives you a name. The next questions are usually more practical: when will it help, why has the dose changed, and what does the next blood test tell you? Start with the question you have today.
Neo-Mercazole at a glance
- Ingredient: carbimazole; the body converts it into methimazole, also called thiamazole.
- Job: reduce new hormone production. It contains no thyroid hormone itself.
- Dose: guided by tests and the prescription, not just the number printed on one tablet.
- Pregnancy: arrange a review before trying; if already pregnant, keep taking the prescribed medicine and contact the doctor as soon as possible.
Start here
Taking Neo-Mercazole
What it does and why feeling better can take time.
Doses and missed tablets
Tablet strength, daily dose and changing instructions.
Side effects
Common problems, practical tips and urgent signs.
Pregnancy and breastfeeding
Planning a review and understanding the options.
Understanding blood tests
Thyroid tests and safety checks do different jobs.
Checking online listings
Partner pharmacy listings and what to check before you order.
Explore the guides
Overactive thyroid: making sense of the diagnosis
A racing heart, feeling hot or losing weight? How an overactive thyroid is checked, why the cause matters, and where carbimazole fits into treatment.
Hyperthyroidism in cats: signs and treatment choices
Eating more but losing weight? How vets check for hyperthyroidism in cats, compare treatment options, and watch kidney function as thyroid levels fall.
Graves’ disease: treatment, remission and what comes next
Why can Graves’ disease return after tablets stop? The autoimmune cause, treatment choices, antibody tests and what remission means day to day.
Questions people ask
Is Neo-Mercazole the same as carbimazole?
Neo-Mercazole is a brand name; carbimazole is the ingredient. Different packs can have different strengths. The name guide helps decode the box.
How long does it take to work?
The NHS says improvement may begin in one to three weeks, with fuller effect in one to two months. Stored hormone helps explain the wait. Read what to expect.
Is carbimazole the same as methimazole?
Carbimazole becomes methimazole in the body, but the prescribed milligrams differ. A switch needs new instructions from the prescriber. Read why the numbers change.
How long will I need to take it?
The cause and response matter. A first adult Graves’ course is often 12–18 months, while some people continue longer. Children’s plans differ. Duration and planned stopping explains the next questions.
About this guide
Neomercazole is an independent guide, written and edited by Peter Dunk and checked against its sources rather than by a doctor. About covers where the facts come from and how to report a mistake.
Where to buy
The online-listing guide links partner pharmacies with carbimazole and methimazole listings. It explains the limits of the checks; a product page is not proof of stock, registration or lawful supply to your country.