Precautions and Warnings With Liothyronine

There are numerous precautions and warnings with liothyronine to be aware of before starting treatment, including information on who should not take this drug. Liothyronine may worsen heart problems and affect your blood sugar levels, so tell your healthcare provider if you have any heart problems or diabetes. Warnings and precautions with liothyronine also apply to people with untreated adrenal insufficiency or untreated hyperthyroidism.

What Should I Tell My Healthcare Provider Before Taking Liothyronine?

You should talk with your healthcare provider prior to taking liothyronine sodium (Cytomel®) if you have:
Also, let your healthcare provider know if you are:
  • Pregnant or thinking of becoming pregnant
  • Breastfeeding.
Make sure to tell your healthcare provider about any other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.

Specific Warnings and Precautions for Liothyronine

Warnings and precautions to be aware of prior to taking liothyronine include the following:
  • People who do not have thyroid problems should never use liothyronine to lose weight. A liothyronine dosage high enough to cause weight loss in such people is often high enough to cause serious or even life-threatening problems.
  • Thyroid hormone medications (including liothyronine) should not be used to treat infertility in people who do not have thyroid problems, as they are not effective for such use.
  • The medication can make heart problems worse. Therefore, if you have heart problems, your healthcare provider should start you at a low liothyronine dosage and slowly increase it. If you notice that liothyronine makes your heart symptoms worse, let your healthcare provider know right away.
  • If you have diabetes, it is a good idea to check your blood sugar more often when starting or stopping liothyronine, or when changing your dose, as the medication can affect your blood sugar.
  • Liothyronine can potentially interact with many other medications (see Drug Interactions With Liothyronine).
  • Liothyronine is considered a pregnancy Category A medication. This means it is safe for use during pregnancy (see Cytomel and Pregnancy).
  • Liothyronine does pass through breast milk in humans, although it is not likely to cause problems. Therefore, if you are breastfeeding or plan to start, discuss this with your healthcare provider prior to taking the drug (see Cytomel and Breastfeeding).
Last reviewed by: Kristi Monson, PharmD
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