Carbimazole Products | Cleanchem - Carbimazole is an antithyroid medication used to treat hyperthyroidism, particularly in conditions like Graves' disease. It works by inhibiting the production of thyroid hormones, helping to normalize thyroid function. Carbimazole is typically used to control symptoms of hyperthyroidism before thyroid surgery or radioactive iodine therapy. Side effects can include skin rashes, joint pain, and, in rare cases, liver toxicity.