Short answer: The Cytomel label has no missed-dose instructions. It describes tablets taken by mouth once daily, usually 25 to 75 mcg for adults with hypothyroidism. Liothyronine (T3) has a biological half-life of about 2 and a half days, shorter than levothyroxine, but a single missed tablet still lowers levels gradually. Ask your prescriber or pharmacist what to do.
| Situation | What the label says |
|---|---|
| Schedule | Once daily by mouth (2.1); usual adult maintenance 25 to 75 mcg (2.2) |
| Missed-dose rule | None in the label |
| Half-life | About 2 and a half days (12.3) |
| Heart symptoms | Dose reduced or held for one week, then restarted lower (5.1) |
No. We checked the Cytomel prescribing information from Pfizer on DailyMed. It has no missed-dose section and no separate patient leaflet. Section 2.1 says Cytomel is taken by mouth once daily, with the dose set for each person and adjusted from checkups and lab tests.
Section 12.3 says the biological half-life is about 2 and a half days. It also says levothyroxine (T4) binds more tightly to blood proteins than T3, which partly explains T4's longer half-life. So T3 levels move faster than T4 levels, but they still do not drop to zero in a day.
This page summarizes FDA labeling. It is not personalized medical advice; confirm what to do with your prescriber or pharmacist.