|Formulary choice||Levothyroxine tablets 25micrograms, 50micrograms, 100 micrograms|
- Prior to treatment, it is important to establish that thyroid stimulating hormone (TSH) is elevated, thus confirming primary hypothyroidism. A normal or low TSH may suggest pituitary or hypothalamic disease for which specialist referral is necessary.
- TSH should be checked 6 weeks after starting levothyroxine or after any change in dose, then annually once stable.
- Alteration in levothyroxine absorption may occur with introduction of other medication such as iron and calcium preparations or drugs altering gastric acid, such as proton pump inhibitors. Thyroid function should be checked 6 weeks after starting such treatment.
- Pregnant women with hypothyroidism should be seen by a specialist for titration of levothyroxine regimens. Upon confirmation of pregnancy it is recommended that, due to the early increase in levothyroxine requirements, levothyroxine dosage is doubled on Saturdays and Sundays until review by a specialist.
- There is insufficient evidence to support the use of liothyronine or Armour® Thyroid for the treatment of hypothyroidism and they are high cost medicines. See PrescQIPP for further details.