Cetirizine (Zyrtec) and Ketamine Therapy | Tovani Health
Zyrtec (Cetirizine) — Second-generation antihistamine (H1 antagonist)
Verdict at Tovani Health
Compatible; mildly sedating in some patients but no other concern.
Cetirizine and ketamine have no clinically significant interaction. Cetirizine is mildly sedating in some patients (more than loratadine, much less than diphenhydramine) but does not stack meaningfully with ketamine.
If you take Zyrtec regularly and are considering at-home ketamine therapy, the combination is generally safe at therapeutic doses. This page covers the brief pharmacologic context and what we do at intake.
How Zyrtec interacts with ketamine
Cetirizine is a peripherally-selective H1 antagonist with limited CNS penetration. Some patients experience mild drowsiness; most do not.
What we do at intake
If you find Zyrtec sedating, take it at night rather than the morning of a session.
Bottom line
Cetirizine and ketamine have no clinically significant interaction. Cetirizine is mildly sedating in some patients (more than loratadine, much less than diphenhydramine) but does not stack meaningfully with ketamine.
Frequently Asked Questions
Is Zyrtec OK before my session?
Yes. If you notice drowsiness from it personally, take it the night before instead.
Ready to find out if at-home ketamine fits your situation?
We’ll note that you’re on Zyrtec (Cetirizine) at intake. The eligibility check takes 5 minutes and gives you an honest answer about whether at-home ketamine fits your specific situation.
FL and NJ residents only. Benjamin Soffer, DO — Tovani Health.
Sources
The verdict and clinical guidance on this page are based on the following peer-reviewed literature and FDA prescribing information.
- Ketamine: A Review of Clinical Pharmacokinetics and Pharmacodynamics in Anesthesia and Pain Therapy. Peltoniemi MA, Hagelberg NM, Olkkola KT, Saari TI.. Clinical Pharmacokinetics. 2016. PMID: 27028535
Comprehensive clinical pharmacokinetics/pharmacodynamics review of ketamine including CYP-mediated drug interactions (CYP3A4, CYP2B6).
Clinically reviewed
Reviewed by Benjamin Soffer, DO on May 16, 2026. Dr. Soffer is a board-certified physician (American Board of Internal Medicine) licensed in Florida and New Jersey, prescribing at-home ketamine therapy through Tovani Health.
This page is general information about how this medication interacts with at-home ketamine therapy at Tovani Health. It is not a substitute for medical advice from your prescribing physician about your specific situation. Always discuss medication changes with the doctor who prescribed them.