Tamiflu with antibiotics: interactions and safety

Antibiotic courses are common, short-term and often combined with chronic medications such as Tamiflu (Oseltamivir). Most antibiotics do not interfere meaningfully with Oseltamivir at 30mg, 45mg, 75mg, 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 Antiviral Medications agents. Rifampicin has the opposite effect, accelerating metabolism. Most penicillins, cephalosporins, fluoroquinolones and tetracyclines have no clinically meaningful interaction with Oseltamivir at 30mg, 45mg, 75mg.

Practical guidance

According to the prescribing information for Oseltamivir, an antibiotic course should be reviewed by the prescriber or pharmacist for known interactions before Tamiflu is co-administered. Adjusted 30mg, 45mg, 75mg dosing or temporary substitution is sometimes preferred for the duration of the antibiotic course.

Frequently asked questions

Can I take Tamiflu during an antibiotic course? ▾

For most common antibiotics, yes. A few classes — notably macrolides and azole antifungals — alter how Oseltamivir is metabolised and may need a temporary 30mg, 45mg, 75mg adjustment. The prescribing pharmacist should review any new antibiotic against the existing Tamiflu regimen.

Will antibiotics make Tamiflu stop working? ▾

Most antibiotics do not affect Tamiflu efficacy. Rifampicin and a few others can lower Oseltamivir levels and reduce effect; in those cases the prescriber may adjust the dose during and shortly after the antibiotic course.

More on Tamiflu

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