Thyroid hormone replacement
Levothyroxine with antibiotics: interactions and safety
Antibiotic courses are common, short-term and often combined with chronic medications such as Levothyroxine (Levothyroxine). Most antibiotics do not interfere meaningfully with Levothyroxine at 25mcg, 50mcg, 75mcg, 100mcg, 150mcg, but a few classes do, and a small number of combinations are best avoided.
Common antibiotic interactions
Macrolides (clarithromycin, erythromycin) and certain antifungals can inhibit hepatic metabolism (CYP3A4) and raise plasma levels of many medications including some Thyroid hormone replacement agents. Rifampicin has the opposite effect, accelerating metabolism. Most penicillins, cephalosporins, fluoroquinolones and tetracyclines have no clinically meaningful interaction with Levothyroxine at 25mcg, 50mcg, 75mcg, 100mcg, 150mcg.
Practical guidance
According to the prescribing information for Levothyroxine, an antibiotic course should be reviewed by the prescriber or pharmacist for known interactions before Levothyroxine is co-administered. Adjusted 25mcg, 50mcg, 75mcg, 100mcg, 150mcg dosing or temporary substitution is sometimes preferred for the duration of the antibiotic course.
Frequently asked questions
Can I take Levothyroxine during an antibiotic course? ▾
For most common antibiotics, yes. A few classes — notably macrolides and azole antifungals — alter how Levothyroxine is metabolised and may need a temporary 25mcg, 50mcg, 75mcg, 100mcg, 150mcg adjustment. The prescribing pharmacist should review any new antibiotic against the existing Levothyroxine regimen.
Will antibiotics make Levothyroxine stop working? ▾
Most antibiotics do not affect Levothyroxine efficacy. Rifampicin and a few others can lower Levothyroxine levels and reduce effect; in those cases the prescriber may adjust the dose during and shortly after the antibiotic course.
Products containing Levothyroxine
More on Levothyroxine
- With alcoholLevothyroxine and alcohol — is it safe to drink?
- With foodShould Levothyroxine be taken with food?
- Side effectsLevothyroxine side effects: common, rare and warning signs
- Dosage guideLevothyroxine dosage guide: how much to take and when
- OnsetHow fast does Levothyroxine start working?
- DurationHow long does Levothyroxine last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.