🩺 NHS Description
Olanzapine is a medicine that helps to manage symptoms of mental health conditions such as: seeing, hearing, feeling or believing things that others do not, feeling unusually suspicious or having muddled thoughts (schizophrenia) feeling agitated or hyperactive, very excited, elated, or impulsive (mania symptoms of bipolar disorder) If you have bipolar disorder, olanzapine can also stop your mania symptoms coming back. It's an antipsychotic medicine that works by affecting chemicals in your brain such as dopamine and serotonin. It does not cure your condition, but it can help with your symptoms. Olanzapine is only available on prescription. It comes as tablets, including tablets that dissolve in your mouth (orodispersible tablets), and an injection.
🩺 Main Uses
Schizophrenia, bipolar disorder (especially mania), short-term agitation.
🧪 The Science & Facts
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Half‑life (t½)
30 h
How long the drug hangs around. Longer half‑life = slower changes.
Time to Peak (Tmax)
6 h
Roughly when you feel the main effect after a dose.
What it hits (receptors)
Primary:
Secondary:
Profile explains sedation, weight gain and orthostasis
How your body processes it (metabolism)
Induces 1A2 → lower plasma levels (may lose effect when smoking stops) • Ritonavir may reduce levels via 1A2/UGT1A4 induction; monitor clinically
⚠️ Warnings
- Expect weight gain, hunger cravings, sleepiness, emotional flattening. Metabolic syndrome and diabetes risk are high. Watch blood sugar and lipids.
⏬ Taper & Withdrawal
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If you’re reducing
Go slow; anticholinergic rebound and insomnia/agitation are possible when reducing. Example: ~10% of current dose every 2–4 weeks; slower if long-term/high dose. Extra care around smoking cessation (levels rise).
Possible withdrawal
Possible cholinergic rebound (nausea, sweating, insomnia, agitation), flu-like malaise; generally milder than clozapine but real, especially after abrupt stops.
Info here is educational, not medical advice. Always taper with prescriber support if possible.
🧠 Trusted External Sources Last reviewed 22 Aug 2025, 21:01 by Connor O’Driscoll
🔗 Interaction Checker
Always verify drug interactions using the Drugs.com Checker.
Need Help Getting Off This?
Try your GP first. If that doesn't help, find local support services who understand tapering.
Find Support Near You →⚠️ Black Box Warning
⚠ Increased mortality in elderly patients with dementia-related psychosis. (Note: the long-acting injection has an additional boxed warning for post-injection delirium/sedation syndrome; this does not apply to oral tablets).
This is a plain‑English summary of headline safety warnings. Talk to a clinician before changing any medication.