Carbimazole

Endocrinology

Endocrinology · Thionamide

Carbimazole

Dose

15–40 mg OD until euthyroid (4–8 wk) then taper to 5–15 mg OD, or block-and-replace with levothyroxine.

Use

Graves' disease and toxic nodular hyperthyroidism.

Monitoring

TFTs q4–6 wk; FBC urgently if sore throat/fever; LFTs if jaundiced.

Side effects

  • Agranulocytosis (rare, urgent FBC)
  • Rash, urticaria
  • Cholestatic jaundice
  • Arthralgia

Pregnancy safety

Switch to propylthiouracil in first trimester (aplasia cutis risk).

Related in WardRound

Always confirm dose against your local formulary / BNF before prescribing.

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