> Western Medicines > Clozapine


Used for: Parkinson's disease, Schizophrenia
Chinese name:

What is Clozapine for?

Clozapine belongs to a class of medications called atypical antipsychotics. It works by balancing the chemicals in your brain and hence restores normal mood, mind, and behaviour. Clozapine is therefore used to treat schizophrenia and Parkinson’s disease.

How to use it?

Clozapine can be taken by mouth. It may be taken with or without food.


12.5 mg once or twice on day 1, followed by 25 mg once or twice on day 2. Then, may increase dose in increments of 25-50 mg daily within 14-21 days up to 300 mg daily in divided doses. Subsequent increments of 50-100 mg once or twice a week if required. Usual dose is 200-450 mg daily, maximum dose is 900 mg daily.

12.5 mg on day 1, increase subsequently in increments of up to 25 mg daily.


Psychoses in Parkinson’s disease
12.5 mg at bedtime, increased in increments of 12.5 mg up to twice weekly up to maximum of 50 mg, according to response. Usual dose is 25-37.5 mg at bedtime, maximum dose is 100 mg daily.


Suicidal behaviour in schizophrenia
Initially 12.5 mg once or twice daily, increase in increments of 25-50 mg daily if tolerated, up to target dose of 300-400 mg daily within 2 weeks. Subsequent increments of up to 100 mg once or twice a week. Maximum dose is 900 mg daily

What are the side effects of Clozapine?

Common side effects of Clozapine include reduced appetite, headache, fever, abnormal sweating, blurred vision, agitation, amenorrhoea, constipation, dizziness, drowsiness, dry mouth, erectile dysfunction, insomnia, Parkinsonism, seizure, tremor and vomiting.

Who should not take Clozapine?

  • People who are allergic to Clozapine or any component of the formulation.

Pharmacist Tips:

  • This medication may cause seizures. Avoid driving or operating machinery until you know how you respond to Clozapine.
  • Avoid abrupt discontinuation to limit withdrawal effects.
  • Do not consume alcohol while on this medication.

Common dosing schedule:
Clozapine is taken once or twice daily. It may be taken with or without food.


This schedule is for reference only, adjustments may be made according to individual needs.


Some common medications Clozapine may interact with:

Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Clozapine in Hong Kong?

In Hong Kong, Clozapine is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.


For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Clozapine in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.

Brands in Hong Kong
Available dosage
  • 25mg / 100mg (Tablets)
Drug class
Sub class
Atypical Antipsychotics
Other drugs in same class