Quetiapine — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Quetiapine?
Quetiapine is a second-generation (atypical) antipsychotic used for schizophrenia, bipolar disorder, and adjunct therapy in depression. This medication is funded by Pharmac under Special Authority for schizophrenia and bipolar disorder.
What is Quetiapine Used For?
Used for schizophrenia, acute mania in bipolar disorder, bipolar depression, and as an adjunct to antidepressants in major depressive disorder.
How Does Quetiapine Work?
Blocks dopamine D2/D3, serotonin 5-HT2A, histamine H1, and alpha-1 adrenergic receptors. Partial agonism at 5-HT1A may contribute to antidepressant effects.
How to Take Quetiapine
Immediate-release: taken 2–3 times daily. Extended-release (Seroquel XR®): once daily in the evening. Doses range from 50–750 mg/day. Titrate gradually to minimise sedation and hypotension.
Common Side Effects of Quetiapine
- Sedation (significant)
- Weight gain and metabolic effects
- Dry mouth
- Constipation
- Dizziness on standing (orthostatic hypotension)
- Elevated liver enzymes
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Metabolic syndrome (diabetes, hyperlipidaemia, obesity — monitor regularly)
- Tardive dyskinesia
- QT prolongation
- Neuroleptic malignant syndrome
- Hypothyroidism (long-term use)
Drug Interactions
Quetiapine may interact with other medicines. Always inform your doctor and pharmacist of all medications you are taking. Key interactions include:
- CYP3A4 inhibitors (ketoconazole, clarithromycin — increase levels)
- Carbamazepine, phenytoin (reduce levels significantly)
- QT-prolonging medicines
- CNS depressants
- Antihypertensives (additive hypotension)
New Zealand Prescribing Information
Quetiapine IR (25–300 mg tablets — Seroquel® and generics) and XR (50–400 mg — Seroquel XR®) are funded under Special Authority. Low-dose quetiapine is commonly prescribed off-label for insomnia in NZ — this carries metabolic and tardive dyskinesia risks and is not a Medsafe-approved indication.
Frequently Asked Questions
Is it safe to use quetiapine just for sleep?
Low-dose quetiapine for insomnia is not Medsafe-approved and carries metabolic risks. Non-pharmacological sleep approaches (CBT-I) should be tried first. Discuss the risks carefully with your doctor.
Does quetiapine cause diabetes?
Quetiapine increases the risk of type 2 diabetes and metabolic syndrome. Regular blood glucose and lipid monitoring, with weight management support, is essential for all long-term users.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: