Levothyroxine (T4)

Main indications

• Hypothyroidism
• Hypopituitarism

Mechanism of action

• Manufactured form of thyroxine

Contraindications and cautions

• Some medications can impair absorption, including PPIs, iron tablets and calcium tablets
• Dose requirements may increase by 25-50% in pregnancy (increased TBG)

Adverse effects

• Usually occur when dose is too high, resulting in hyperthyroidism - increased appetite, weight loss, increased sweating etc.

Administration

• PO before breakfast

Carbimazole

Main indications

• First line for hyperthyroidism

Mechanism of action

• Inhibition of TPO thereby blocking thyroid hormone synthesis

Contraindications and cautions

• Risk of aplasia cutis in early pregnancy