Carbimazole 5mg
Tablets
Antithyroid preparation Composition:
Each tablet contains:
Carbimazole 5 mg. Properties:
Carbimazole: is a thiourea derivative used in the treatment of hyperthyroidism.
Carbimazole: blocks the production of thyroid hormones through inhibition of thyroid peroxidase and inhibition of the coupling of iodotyrosines to form iodothyronines .
Carbimazole: does not block the release of stored thyroid hormones . Pharmacokinetics :
Carbimazole is rapidly absorbed after oral administration and completely metabolized to methimazole the active antithyroid metabolite in the blood.
No plasma protein binding.
Apparent plasma half life for methimazole is 3 to 6 hours.
Methimazole is widely distributed throughout the body ,it crosses the placenta and is excreted in milk.
Carbimazole is almost completely excreted in urine in 24 hours as methimazole or its conjugates. Indications & usage :
To control hyperthyroidism in the following three ways :
- As a definitive treatment to control hyperthyroidism .
- In conjunction with radioactive iodine .
- To control the disorder in preparation for surgical treatment .
N.B. The clinical effects may not be apparent for several days until stores of
thyroid hormones are depleted . Contra-indications :
- Hypersensitivity to carbimazole
- Tracheal obstruction .
- Breast feeding. Side effects:
The drug may induce some adverse effects in some people ,they occur most
commonly in the first 2 months of treatment and include :
Mild leucopenia, skin rashes, pruritis, headache, arthralgia, gastrointestinal
disorders and hepatic dysfunction but they can be treated with antihistaminic without discontinuing treatment . Skin , bone marrow suppression including (pancytopenia & agranulocytosis)
are the most serious adverse effect but its incidence may be reduced with
doses below 30 mg daily) . Drug interactions :
Carbimazole increases the clearance of prednisolone .
Carbimazole produces rise in thyophylline half life.
Warnings & precautions:
· Used cautiously in Pregnancy & lactation.
· Patients should be instructed to seek a physician in the following conditions:
- Immediately the development of mouth ulcers, sore throat, fever or rashes
which may be indicated abnormalities in the blood. Treatment should be
discontinued if there is any clinical or laboratory evidence of neutropenia .
- The use of the drug should be very cautious in patients with a pre-existing
blood disorder or impairment of hepatic function
- Total and differential leucocytic counts are recommended at periodic
intervals. Dosage & administration:
The usual initial dosage is 2-3 tablets every 8 hours to be maintained until the patient becomes euthyroid which usually occur after 4-8 weeks then the dose is gradually reduced to the maintenance doses which are 5-15 mg daily in divided doses. Children may be given carbimazole in an initial dose of 250 mcg/kg 3 times daily adjusted according to response, treatment in children should be undertaken by a specialist. Packing :
Carton box containing 50 tablets . Storage :
Store at a cool and dry place | 
