Drug interactions
Levothyroxine + Rifampin
Severity: Moderate
Levothyroxine and Rifampin: moderate 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
Rifampin is a strong enzyme inducer and can increase levothyroxine clearance. Patients on replacement therapy may develop elevated TSH and hypothyroid symptoms.
What this interaction means in plain words
Levothyroxine and Rifampin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Induction of hepatic metabolism and biliary excretion of thyroid hormone increases levothyroxine clearance.
What to do
Check TSH 4 to 6 weeks after starting or stopping rifampin and increase the levothyroxine dose as required.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Levothyroxine
Frequently asked questions
Can I take Levothyroxine with Rifampin?
MediHelp rates the interaction as moderate. Levothyroxine and Rifampin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Rifampin is a strong enzyme inducer and can increase levothyroxine clearance. Patients on replacement therapy may develop elevated TSH and hypothyroid symptoms.
How serious is the interaction between Levothyroxine and Rifampin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Check TSH 4 to 6 weeks after starting or stopping rifampin and increase the levothyroxine dose as required.
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.
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