Carbimazole
Indications
Carbimazole is used for:
Grave's disease, Hyperthyroidism, Diabetic nephropathy, Preparation for thyroidectomy
Adult Dose
Oral
Hyperthyroidism, Adjunct to radio-iodine therapy, Grave's disease, Preparation for thyroidectomy
Adult: Initially, 20-60 mg daily as a single or divided dose, reduced gradually once euthyroidism is achieved. Maintenance: 5-15 mg daily for at least 1 yr or 18 mth.
Hepatic impairment: Severe: Contraindicated.
Child Dose
Oral
Hyperthyroidism; Adjunct to radio-iodine therapy; Preparation for thyroidectomy
Child: 3-17 yr Initially, 15 mg daily, adjusted according to response.
Renal Dose
Administration
May be taken with or without food. Take consistently w/ or w/o meals.
Contra Indications
Hyperthyroidism due to nodular goitre.
Precautions
Liver diseases, pregnancy, lactation.
Pregnancy-Lactation
Interactions
Increased serum levels of theophylline or may develop toxicity. May enhance the effect of anticoagulants.
Potentially Fatal: Increased sensitivity to warfarin in hyperthyroidism and careful control required as patient is rendered euthyroid.
Adverse Effects
Side effects of Carbimazole :
Mild leucopaenia, sore throat, mouth ulcers, fever, bruising, malaise; rarely cholestatic jaundice; nephrotic syndrome. Nausea, loss of taste, headache, arthralgia, alopoecia.
Potentially Fatal: Agranulocytosis, aplastic anaemia, hypoprothrombinaemia, neutropaenia; hypothyroidism and goitre.
Mechanism of Action
Carbimazole is metabolised to methimazole which is responsible for its antithyroid action. It blocks the production of thyroid hormones by inhibiting thyroid peroxidase.