Zyrtec with antibiotics: interactions and safety
Antibiotic courses are common, short-term and often combined with chronic medications such as Zyrtec (Cetirizine). Most antibiotics do not interfere meaningfully with Cetirizine at 5mg, 10mg, 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 Allergy and Antihistamines agents. Rifampicin has the opposite effect, accelerating metabolism. Most penicillins, cephalosporins, fluoroquinolones and tetracyclines have no clinically meaningful interaction with Cetirizine at 5mg, 10mg.
Practical guidance
According to the prescribing information for Cetirizine, an antibiotic course should be reviewed by the prescriber or pharmacist for known interactions before Zyrtec is co-administered. Adjusted 5mg, 10mg dosing or temporary substitution is sometimes preferred for the duration of the antibiotic course.
Frequently asked questions
Can I take Zyrtec during an antibiotic course? ▾
For most common antibiotics, yes. A few classes — notably macrolides and azole antifungals — alter how Cetirizine is metabolised and may need a temporary 5mg, 10mg adjustment. The prescribing pharmacist should review any new antibiotic against the existing Zyrtec regimen.
Will antibiotics make Zyrtec stop working? ▾
Most antibiotics do not affect Zyrtec efficacy. Rifampicin and a few others can lower Cetirizine levels and reduce effect; in those cases the prescriber may adjust the dose during and shortly after the antibiotic course.
More on Zyrtec
- With alcoholZyrtec and alcohol — is it safe to drink?
- With foodShould Zyrtec be taken with food?
- Side effectsZyrtec side effects: common, rare and warning signs
- Dosage guideZyrtec dosage guide: how much to take and when
- OnsetHow fast does Zyrtec start working?
- DurationHow long does Zyrtec last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.