What does it do?

Clozapine is used to treat and prevent schizophrenia. It is also sometimes used for other conditions.

Before you start

• Tell your doctor if you have heart, liver, blood, bowel, bladder or prostate problems.
• Tell your doctor if you have diabetes, Parkinson’s disease, angle-closure glaucoma, have ever had a seizure, blood clot, stroke or ‘mini-stroke’, or if you have experienced strange body movements with another medicine.
• Tell your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
• You will need a blood test before you start taking clozapine, then every week for 18 weeks, and then every four weeks after that while taking clozapine. This is because clozapine can sometimes lower the number of white cells in your blood, making it harder for your body to fight off infections.
• Your doctor may do a heart test (ECG) before you start and while you are taking clozapine.

How should you take it?

Take clozapine regularly as directed with a glass of water.

What if you forget a dose?

Take the missed dose as soon as possible. If it is close to the time for your next dose, skip the missed dose and carry on as normal. Do not take two doses at the same time.
If you miss more than two days in a row, talk to your doctor before you take any more. You will need to start again at a lower dose with weekly blood tests.

Can you take other medicines?

Some medicines available without a prescription may react with clozapine including:

• some antihistamines or anti-nausea medicines such as promethazine (e.g. Phenergan®), hyoscine (e.g. Scopoderm®), meclozine (e.g. Sea-legs®)
• trimethoprim

Tell your pharmacist or doctor about all medicines or treatments that you may be taking, including vitamins, herbal products (e.g. St John's wort, kava) or recreational drugs.

What side effects might you notice?

Side Effects	Recommended action
Reduced number of blood cells that fight infections in your body - symptoms include: fever, chills, sore throat or generally feeling unwell Confusion Feeling restless, strange or uncontrolled movements, tremor, stiffness Fast or irregular heartbeat, chest pain, fainting Symptoms of a blood clot including: sudden shortness of breath, swelling or pain in one leg Seizures Prolonged erection (longer than four hours)	Tell your doctor immediately
Constipation	Tell your doctor
Drowsiness, dizziness, weakness, headache, anxiety, blurred vision Weight gain More saliva than usual, drooling Stomach upset Peeing when you don’t want to, bed-wetting, trouble peeing Less interest in sex, impotence	Tell your doctor if troublesome

If you notice any other effects, discuss them with your doctor or pharmacist.

Other information:

• Clozapine can impair your ability to do tasks such as driving or using machines. Alcohol makes this worse. Discuss your risk with your health professional. (search NZTA - Are you safe to drive?)
• Smoking can change the effect of clozapine. Tell your doctor if you give up, cut down or start smoking.
• Clozapine reduces your body’s ability to maintain a normal temperature. Be careful of becoming too cold or too hot. When exercising, drink plenty of water.
• You have an increased risk of getting diabetes while taking clozapine. Discuss with your doctor.
• Do not stop taking clozapine without talking to your doctor first.