Synthroid should ideally be taken on an empty stomach with a full glass of water, 30 to 60 minutes before food. Except for water, drinks like coffee, tea, and juice should not be consumed at the same time as Synthroid as they could potentially decrease absorption of the drug.
Both the rate and extent of absorption for Synthroid is well known to be negatively affected by a number of medications and food.
Nearly every study concerning Synthroid states that it is best absorbed in a fasted state, and the prescribing information for the drug recommends for it to be taken as follows:
Administer SYNTHROID as a single daily dose, on an empty stomach, one-half to one hour before breakfast.
One of the reasons as to why food and other drugs can affect Synthroid absorption is simply due to the extremely low dosages used.
Remember that Synthroid is dosed in micrograms, not milligrams. One microgram is 1/1000th of one milligram, so we are talking very low doses here.
The key to optimal therapy and finding the right dose is consistency in administration. You want to take Synthroid the same way every day.
Dosage adjustments for Synthroid are usually done in 12.5 to 25 mcg intervals, so even a minor change in how your body absorbs it can make a significant difference in your thyroid hormone levels.
Coffee, both caffeinated and decaffeinated, have been shown time and again in studies to decrease total Synthroid absorption.
One study reported that coffee decreases the total absorption of levothyroxine by about 30%.
Even the medical guidelines for the treatment of hypothyroidism touches on coffee:
Absorption studies performed in these patients and in volunteers support the role of coffee in reducing LT4 [levothyroxine] absorption. Compared with water, coffee reduced both the maximum concentration (Cmax) and the AUC documented during these absorption studies.
With a decrease in absorption, you could expect TSH (thyroid stimulating hormone) levels to increase, which may be noticeable in your lab results.
It doesn't appear as though the caffeine content in coffee is the main reason as to why it decreases absorption. Decaffeinated coffee has also been shown to have a negative effect.
How Long To Wait
In terms of how long to wait to take Synthroid after drinking coffee, one study evaluated the effects of coffee on a 200 mcg dose of levothyroxine.
The study found that compared with water, coffee did significantly decrease levothyroxine concentrations if consumed at the same time. However, coffee taken 60 minutes before or after levothyroxine had no significant effect on absorption.
Other Dosage Forms
Interestingly enough, several studies have reported that non-tablet versions of levothyroxine may not be affected by coffee.
Specifically, studies have reported that both the liquid and soft gel formulations of levothyroxine (Tirosint) are unlikely to have their absorption significantly affected by coffee and most other foods.
One study reported the following results:
The main finding of this study is that both the liquid and soft gel capsule formulations of L-T4 [levothyroxine] can be taken with breakfast. Priority should however be given to the liquid L-T4 formulation in those patients where even a small change in fT4 and fT3 levels is to be avoided.
Until we have more data on which formulation of levothyroxine may be safest to take with coffee, the recommendation to take levothyroxine on an empty stomach still remains, however.
SummaryCoffee could potentially decrease Synthroid (levothyroxine) absorption. It is recommended to be taken on an empty stomach, about 30 to 60 minutes before food or drink (except water).
- ^ Elsevier ClinicalKey: Synthroid Monograph. ClinicalKey
- RxAbbvie Synthroid Prescribing Information.
- PubMed Altered intestinal absorption of L-thyroxine caused by coffee.
- PubMed Guidelines for the Treatment of Hypothyroidism: Prepared by the American Thyroid Association Task Force on Thyroid Hormone Replacement.
- PubMed Clinical relevancy of the levothyroxine-continuous enteral nutrition interaction.
- PubMed Thyroid Hormone Profile in Patients Ingesting Soft Gel Capsule or Liquid Levothyroxine Formulations with Breakfast.