Drug interactions
Caffeine + Levothyroxine
Severity: Minor
Caffeine and Levothyroxine: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Coffee and other caffeinated drinks taken with oral levothyroxine can reduce its absorption and lower thyroid hormone exposure. Additive stimulant effects such as tachycardia are also possible but are generally minor.
What this interaction means in plain words
Caffeine and Levothyroxine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Caffeine belongs to Miscellaneous; Levothyroxine belongs to Endocrine.
Why it happens
Caffeinated beverages impair intestinal absorption of levothyroxine, probably through binding or altered gut motility, and caffeine adds to sympathomimetic effects.
What to do
Take levothyroxine on an empty stomach with water, and wait 30 to 60 minutes before coffee or other caffeinated drinks. Monitor TSH if the patient's caffeine habits change substantially.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Caffeine and Levothyroxine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Levothyroxine
Other interactions of Caffeine
- Caffeine + Ephedrine Major
- Caffeine + Fezolinetant Major
- Caffeine + Methylenedioxymethamphetamine Major
- Caffeine + Selegiline transdermal Major
- Adenosine + Caffeine Moderate
- Benzphetamine + Caffeine Moderate
Frequently asked questions
Can I take Caffeine with Levothyroxine?
MediHelp rates the interaction as minor. Caffeine and Levothyroxine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Coffee and other caffeinated drinks taken with oral levothyroxine can reduce its absorption and lower thyroid hormone exposure. Additive stimulant effects such as tachycardia are also possible but are generally minor.
How serious is the interaction between Caffeine and Levothyroxine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Take levothyroxine on an empty stomach with water, and wait 30 to 60 minutes before coffee or other caffeinated drinks. Monitor TSH if the patient's caffeine habits change substantially.
What other medicines interact with Levothyroxine?
MediHelp also lists interactions of Levothyroxine with, for example, Cholestyramine, Sodium iodide i-131, Tiratricol. The full list is on the Levothyroxine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
