Medicines & Supplements A to Z > Quetiapine

Quetiapine

Last updated on 18/03/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions   |   Tips   |   Where To Buy  

GENERIC NAME: Quetiapine

CHINESE NAME: 喹硫平

BRAND NAME(S) IN HONG KONG: Seroquel 仙樂快, Seroquel XR (extended-release)

DRUG CLASS: Antipsychotic (second generation) 

USED FOR: Bipolar disorder, depression, schizophrenia 

OTHER DRUGS IN THE SAME CLASS: Amisulpride, Aripiprazole, Clozapine, Olanzapine, Risperidone

What is Quetiapine for?

Quetiapine is second-generation antipsychotic. It works by balancing the chemicals in your brain and hence improves your mood, mind, and behaviour. Quetiapine is therefore used to treat different mood disorders, including schizophrenia, both mania and depression in bipolar disorder and major depression.

How to use it?

Quetiapine can be taken orally as conventional tablets, extended-release tablets, and prolonged-release tablets. The dosages for different uses, preparations, and age groups are listed below: 

For schizophrenia 

Orally using conventional tablets 

Adult
Day 1: 25 mg twice daily
Day 2: 50 mg twice daily
Day 3: 100 mg twice daily
Day 4: 150 mg twice daily 

The dose should be adjusted according to your response. The usual dose is 300-450 mg daily in 2 divided doses and the maximum daily dose is 750 mg. The dose should be increased slowly and the dose used in elderly should be lower.

Orally using extended-release / modified-release tablets 

Adult
Day 1: 300 mg once daily
Day 2: 600 mg once daily

The dose should be adjusted according to your response. The usual dose is 600 once daily, while the maximum daily dose is 800 mg and it can only be used under specialist supervision. 

Elderly
Start with 50 mg daily. The dose should be adjusted in steps of 50 mg according to your response. 

For mania in bipolar disorder 

Orally using conventional tablets 

Adult
Day 1: 50 mg twice daily
Day 2: 100 mg twice daily
Day 3: 150 mg twice daily
Day 4: 200 mg twice daily 

The dose should be adjusted in steps of up to 200 mg daily according to your response. The usual dose is 400-800 mg daily in 2 divided doses, while the maximum daily dose is 800 mg. The dose should be increased slowly and the dose used in elderly should be lower.

Orally using extended-release / modified-release tablets 

Adult
Day 1: 300 mg once daily
Day 2: 600 mg once daily

The dose should be adjusted according to your response. The usual dose is 400-800 mg once daily. 

Elderly
Start with 50 mg daily. The dose should be adjusted in steps of 50 mg according to your response. 

For depression in bipolar disorder

Orally using conventional tablets 

Adult
Day 1: 50 mg once daily at bedtime
Day 2: 100 mg once daily at bedtime
Day 3: 200 mg once daily at bedtime 

The dose should be adjusted according to your response. The usual dose is 300 mg once daily, while the maximum daily dose is 600 mg. The dose should be increased slowly and the dose used in elderly should be lower.

Orally using extended-release / modified-release tablets 

Adult
Day 1: 50 mg once daily at bedtime
Day 2: 100 mg once daily at bedtime
Day 3: 200 mg once daily at bedtime
Day 4: 300 mg once daily at bedtime

The dose should be adjusted according to your response. The usual dose is 300 mg once daily, while the maximum daily dose is 600 mg. 

For prevention of mania and depression in bipolar disorder 

Orally using conventional tablets 

Adult
The dose used should be the lowest effective dose. The usual dose is 300-800 mg daily in 2 divided doses. 

Orally using extended-release / modified-release tablets 

Adult
The dose used should be the lowest effective dose. The usual dose is 300-800 mg once daily. 

As an adjunct for major depression 

Orally using conventional tablets 

Adult
50 mg once daily at bedtime for 2 days, followed by 150 mg once daily for 2 days. The dose should be adjusted according to your response and the usual dose is 150-300 mg once daily. 

Orally using extended-release / modified-release tablets 

Adult
Start with 50 mg once daily for 3 days. The dose can be increased to 100 mg once daily for 4 days if necessary, followed by dose adjustment in steps of 50 mg. The dose should be adjusted according to your response. The usual dose is 50-300 mg once daily. Before day 22, the dose must be less than 300 mg.

What are the side effects of Quetiapine?

Common side effects of Quetiapine include irregular heart rhythms, constipation, dizziness, drowsiness, dry mouth, erectile dysfunction, high prolactin levels, low white blood cell count, movement disorders, parkinsonism, rash, seizure, tremor, urinary retention, vomiting, and increased weight. Metabolic changes may also be observed including high blood pressure, high sugar levels, and high lipid levels.

Who should not take Quetiapine?

Anyone who has an allergy to Quetiapine or any component of the product.

Pharmacist Tips:

– Avoid alcohol while you are taking Quetiapine.
– Do not discontinue Quetiapine abruptly on your own. This can result in withdrawal symptoms, such as insomnia and headache. Always discuss with your doctor or pharmacist. 

Common dosing schedule:
Quetiapine can be taken with or without food. 

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

Some common medications quetiapine may interact:
– Antidiabetic agents, e.g. Metformin, Insulin
– Azelastine
– Blood pressure lowering drugs, e.g. Atenolol, Lisinopril, Nifedipine
– Bupropion
– Kava Kava
Metoclopramide 

This medication interacts with a number of drugs, please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Quetiapine in Hong Kong?

In Hong Kong, Quetiapine 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 Quetiapine 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.