Drug interactions
Cetirizine + Fentanyl
Severity: Moderate
Cetirizine and Fentanyl: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Fentanyl is a potent opioid causing sedation and respiratory depression, and sedating antihistamines can add to CNS depression. Cetirizine is less sedating than older antihistamines, but additive drowsiness and impaired alertness can occur.
What this interaction means in plain words
Cetirizine and Fentanyl can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Cetirizine belongs to Respiratory; Fentanyl belongs to Musculoskeletal.
Why it happens
Additive CNS depressant effects.
What to do
Monitor sedation and respiratory status, particularly when starting or increasing fentanyl; use the lowest effective doses of both.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Cetirizine
- Acrivastine + Cetirizine Moderate
- Amisulpride + Cetirizine Moderate
- Asenapine + Cetirizine Moderate
- Avapritinib + Cetirizine Moderate
- Benzhydrocodone / acetaminophen + Cetirizine Moderate
- Brexpiprazole + Cetirizine Moderate
Other interactions of Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Frequently asked questions
Can I take Cetirizine with Fentanyl?
MediHelp rates the interaction as moderate. Cetirizine and Fentanyl can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Fentanyl is a potent opioid causing sedation and respiratory depression, and sedating antihistamines can add to CNS depression. Cetirizine is less sedating than older antihistamines, but additive drowsiness and impaired alertness can occur.
How serious is the interaction between Cetirizine and Fentanyl?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor sedation and respiratory status, particularly when starting or increasing fentanyl; use the lowest effective doses of both.
What other medicines interact with Cetirizine?
MediHelp also lists interactions of Cetirizine with, for example, Acrivastine, Amisulpride, Asenapine. The full list is on the Cetirizine page.
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