P : Caution when used during pregnancy
L : Caution when used during lactation
|| See TERMINOLOGY & ABBREVIATIONS ||
|Indication(s) & Dosage||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.
Child: 4-12 yr: Initially, 15 mg daily.
|Administration||May be taken with or without food.
|Contraindications||Hyperthyroidism due to nodular goitre.|
|Special Precautions||Liver diseases, pregnancy, lactation.|
|Adverse Drug Reaction(s)||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.
|Drug Interactions||Potentially Fatal: Increased sensitivity to warfarin in hyperthyroidism and careful control required as patient is rendered euthyroid. Please consult detailed drug interactions before prescribing.|
|Pregnancy Category (FDA)||Category D: There is positive evidence of human foetal risk, but the benefits from use in pregnant women may be acceptable despite the risk (e.g., if the drug is needed in a life-threatening situation or for a serious disease for which safer drugs cannot be used or are ineffective).|
|Storage||Oral: Store below 25Â°C.|
|Pharmacology||Carbimazole is metabolised
to methimazole which is responsible for its antithyroid action. It blocks the production of thyroid hormones by inhibiting thyroid peroxidase.
Absorption: Rapid from the GIT (oral); peak plasma concentrations after 1-2 hrs.
Distribution: High concentrations in the thyroid gland; crosses the placenta; enters breast milk.
Metabolism: Hepatic; converted to methimazole.
Excretion: Urine (<12% unchanged drug); 3-6 hrs (elimination half-life).
|ATC Classification||H03BB01 - carbimazole; Belongs to the class of sulfur-containing imidazole derivative agents. Used in the management of thyroid diseases.|