Short answer: The Tirosint label has no missed-dose instructions, in either the prescribing information or the Patient Information. It describes one dose a day on an empty stomach, half an hour to an hour before breakfast, with the capsule swallowed whole. Levothyroxine has a half-life of 6 to 7 days. Ask your prescriber or pharmacist what to do.
| Situation | What the label says |
|---|---|
| Schedule | Once daily on an empty stomach, one-half to one hour before breakfast; swallowed whole (2.1) |
| Missed-dose rule | None in the prescribing information or Patient Information |
| Half-life of T4 | 6 to 7 days with normal thyroid levels (12.3, Table 6) |
| Poor response at high doses | May point to missed doses, poor absorption or drug interactions (2.3) |
No. We checked the Tirosint prescribing information and Patient Information from IBSA on DailyMed. Neither says what to do after a missed dose. Section 2.1 says Tirosint is taken once daily on an empty stomach, one-half to one hour before breakfast, and at least 4 hours before or after drugs that interfere with its absorption. Capsules are swallowed whole, not cut, crushed or chewed.
Table 6 in section 12.3 gives a half-life for levothyroxine (T4) of 6 to 7 days in people with normal thyroid levels, 3 to 4 days with an overactive thyroid and 9 to 10 days with an underactive one. Levels fall only a small part of the way in one day.
Section 2.3 says a poor response to more than 300 mcg a day is rare and may point to missed doses, poor absorption, drug interactions or a mix of these.
This page summarizes FDA labeling. It is not personalized medical advice; confirm what to do with your prescriber or pharmacist.