Triazole antifungal
Fluconazole with thyroid medication (levothyroxine)
Levothyroxine is one of the most prescribed medications worldwide, and many adults on it also use chronic medications such as Fluconazole (Fluconazole). The combination is generally safe, but levothyroxine's narrow therapeutic index and finicky absorption mean a few practical points matter more than for most other co-administered drugs at 50mg, 100mg, 150mg, 200mg.
How Fluconazole affects thyroid medication
Levothyroxine absorption is sensitive to timing relative to food, calcium, iron and several medications. Whether Fluconazole interferes depends on Fluconazole — most agents in Triazole antifungal have no clinically meaningful effect on thyroid hormone levels, but a small number affect TSH or T4 free fraction. Fluconazole is a triazole antifungal that inhibits the cytochrome P450-dependent enzyme lanosterol 14-alpha-demethylase, blocking the synthesis of ergosterol from lanosterol.
Practical timing
According to standard endocrine practice, levothyroxine is taken on an empty stomach at least 30 minutes before food and 4 hours from interacting medications. Fluconazole at 50mg, 100mg, 150mg, 200mg can usually be taken at any time relative to the levothyroxine dose, but the prescribing information for Fluconazole should be checked for specific timing instructions.
Frequently asked questions
Will Fluconazole affect my thyroid levels? ▾
Most Triazole antifungal medications do not directly affect thyroid hormone levels at 50mg, 100mg, 150mg, 200mg. Some affect TSH testing, hormone-binding proteins or T4 free fraction in subtle ways. Routine thyroid function tests every few months catch any meaningful drift.
When should I take Fluconazole relative to levothyroxine? ▾
Levothyroxine is taken on an empty stomach with at least a 30-minute fast and 4-hour separation from interacting medications. Fluconazole at 50mg, 100mg, 150mg, 200mg usually has no specific timing constraint relative to levothyroxine; the pharmacist confirms based on the prescribing information for Fluconazole.
Products containing Fluconazole
More on Fluconazole
- With alcoholFluconazole and alcohol — is it safe to drink?
- With foodShould Fluconazole be taken with food?
- Side effectsFluconazole side effects: common, rare and warning signs
- Dosage guideFluconazole dosage guide: how much to take and when
- OnsetHow fast does Fluconazole start working?
- DurationHow long does Fluconazole last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.