Zyrtec (Cetirizine) and Panadeine (Paracetamol/Codeine): Interaction Risk

Combining These Medications

Concurrent use may increase central nervous system depression.

Mechanism

• Cetirizine: second-generation antihistamine; low sedation but some CNS penetration.
• Codeine: opioid metabolized to morphine → sedation, respiratory depression.
• Additive drowsiness, dizziness, impaired psychomotor performance.

Recommendation

Avoid driving/operating machinery. Consult pharmacist/physician before combining, especially if elderly, on other sedatives, or with respiratory conditions. Alternative analgesics (ibuprofen, paracetamol alone) may be safer.