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THYROXINE - a patient's guide


Thyroxine is used in the treatment of an underactive thyroid gland. This article discusses how it is used and its possible side effects.

BRAND NAME: Eltroxin

USE: Thyroid hormone (hypothyroidism)

This medicine is primarily indicated for the treatment of hypothyroidism (underactive thyroid gland), where thyroxine is used as replacement therapy in people having a lower thyroid function than normal. Treatment is usually long term as it is replacing thyroid hormone the body is not producing. The dosage is usually adjusted according to response and blood test results.


Patients with heart disease (angina) should start the medication cautiously on a low dose and build up as needed under medical supervision.

Other cautions to be aware of include:

  • Adrenal insufficiency
  • Breastfeeding
  • Thyrotoxic crisis ('thyroid storm')
  • Elderly - slowly on a low dose and build up if needed.
  • Diabetics (raises sugar levels)

Side effects:

Dose related:
  • chest pain (also an increase in heartbeat)
  • muscle cramps
  • stomach upset
  • weight loss
  • restlessness and insomnia
  • headache
  • sweating and hot flushes

Side effects usually reside after a dose reduction is made by your doctor.


Results in excess irritability, confusion, sweating and other side effects (seek urgent medical help).


Thyroxine increases the effect of warfarin, tricyclic antidepressants and amiodarone.

Oral contraceptives, anticonvulsants, cholestyramine and rifampicin may reduce efficacy.

Patient information:

Follow the instructions on the label of this medicine.

Used as maintenance therapy therefore should be taken regularly (do not stop taking this medicine unless directed by your doctor). If you miss a dose, it is not necessary to take an extra dose, as the drug is very long-acting.

Contact your doctor or seek medical help if side effects are severe or ongoing.

See also:

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