Carbimazole

It acts at 3 steps in the synthesis of thyroid hormone, inhibit oxidatio of iodide, iodination of tyrosine residues, coupling of iodotyrosine residues to form T3 & T4. It does not interfere with trapping of iodide and do not modify the action of T3 and T4 on peripheral tissues or on pituitary. Goiter is not the result of potentiation of TSH action on thyroid, but is due to increased TSH release as a consequence of reduction in feed back inhibition.

Indications

Primary or secondary thyrotoxicosis, thyrotoxicosis prior to thyroidectomy, intractable congestive cardiac failure, angina pectoris, and paroxysmal tachycardia.

Dosage

Mild cases. Initially 15-20 mg daily in divided dosage. Moderate cases : 30 mg daily in divided dosage. Severe cases 40-45 mg daily in divided dosage. Maint. : 2.5-25 mg daily divided dosage.

Contra-Indications

Tracheal obstruction.Lactation.

Special Precautions

Stop medication & report to physician in case symptoms like sore throat fever or rash appear, pregnancy.

Side Effects

Bone marrow depression, mouth ulcers, rashes, nausea, headache, arthralgia. Loss or graying of hair, fever & liver damage, agranulocytosis.

Drug Interactions

Increased sensitivity to warfarin in hyprthyroidism.