Drug interactions
Apalutamide + Levothyroxine
Severity: Moderate
Apalutamide and Levothyroxine: 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
Apalutamide induces drug-metabolizing enzymes, including UGT, which can speed up the clearance of levothyroxine. Thyroid hormone levels may fall and hypothyroidism may emerge or worsen in patients on a stable dose.
What this interaction means in plain words
Apalutamide and Levothyroxine 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.
Apalutamide belongs to Endocrine; Levothyroxine belongs to Endocrine.
Why it happens
Induction of UGT-mediated glucuronidation increases hepatic clearance of levothyroxine.
What to do
Check TSH and free T4 about 6 to 8 weeks after apalutamide is started or stopped. Increase the levothyroxine dose as needed and reduce it again if apalutamide is discontinued.
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
Other interactions of Apalutamide
- Apalutamide + Cabotegravir Contraindicated
- Apalutamide + Cobicistat Contraindicated
- Apalutamide + Doravirine Contraindicated
- Apalutamide + Elbasvir / grazoprevir Contraindicated
- Apalutamide + Ensitrelvir Contraindicated
- Apalutamide + Fostemsavir Contraindicated
Frequently asked questions
Can I take Apalutamide with Levothyroxine?
MediHelp rates the interaction as moderate. Apalutamide and Levothyroxine 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. Apalutamide induces drug-metabolizing enzymes, including UGT, which can speed up the clearance of levothyroxine. Thyroid hormone levels may fall and hypothyroidism may emerge or worsen in patients on a stable dose.
How serious is the interaction between Apalutamide and Levothyroxine?
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 and free T4 about 6 to 8 weeks after apalutamide is started or stopped. Increase the levothyroxine dose as needed and reduce it again if apalutamide is discontinued.
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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