Can I take Benylin dry coughs and Clozapine together?

Why this happens

Both medicines affect the central nervous system (brain) and have 'anticholinergic' effects. When taken together, their sedative effects add up, making you much sleepier than usual. Additionally, the active ingredient in this Benylin (diphenhydramine) can slow down how quickly your liver breaks down clozapine, potentially leading to higher levels of clozapine in your blood.

What you should do

You should avoid taking Benylin Dry Coughs while you are on clozapine If you have a cough, speak to your pharmacist or doctor about safer alternatives that do not cause drowsiness (such as simple linctus). If you have already taken both and feel extremely sleepy or have trouble breathing, seek medical help immediately.

Important precautions

Infection or flu-like symptoms

You must have regular blood tests because clozapine can cause a serious drop in white blood cells (agranulocytosis). Contact your doctor immediately if you develop a fever, sore throat, or any signs of infection.

Constipation

Clozapine can cause severe constipation which may lead to serious bowel obstruction. You must tell your doctor if you are constipated or if your bowel habits change.

Concurrent use of both medicines

Do not take these together without medical advice. Benylin Dry Coughs contains ingredients that can increase the levels of clozapine in your blood, significantly increasing the risk of serious side effects like seizures.

Food and drink warnings

Caffeine (coffee, tea, cola, energy drinks)

Caffeine can increase the levels of clozapine in your blood, which may increase the risk of side effects. If you suddenly stop or significantly reduce your caffeine intake, your clozapine levels may drop, potentially making the medicine less effective. Try to keep your caffeine consumption consistent and inform your doctor if you plan to change your habits.

Alcohol

You should avoid drinking alcohol while taking these medicines. Alcohol can significantly increase the sedative effects (drowsiness and dizziness) of both clozapine and the ingredients in Benylin, which can impair your ability to drive or operate machinery and may affect your breathing.

Using other medicines

Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.

Disclaimer

This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.