Olanzapine
Olanzapine is an atypical antipsychotic indicated for schizophrenia, bipolar I disorder (manic or mixed episodes), and as maintenance treatment for bipolar disorder. It is also available as a long-acting injection and in combination with fluoxetine for treatment-resistant depression and bipolar depression.
Clinical Overview
Primary Clinical Applications
Olanzapine is indicated for schizophrenia in adults and adolescents (13-17 years), acute treatment of manic or mixed episodes in bipolar I disorder, and maintenance treatment of bipolar disorder. It shows particular efficacy in preventing mood episodes and managing agitation.
Mechanism and Clinical Benefits
Olanzapine antagonizes multiple neurotransmitter receptors including dopamine D2, serotonin 5-HT2A, histamine H1, and muscarinic receptors. This broad receptor profile contributes to its efficacy but also to its side effect profile, particularly metabolic effects.
Formulation Options
Available as oral tablets, orally disintegrating tablets, intramuscular injection for agitation, and long-acting injection (Zyprexa Relprevv) for maintenance treatment. Each formulation offers specific advantages for different clinical situations.
Key Clinical Points
Heaviest metabolic burden in the class
Weight gain, hyperglycaemia, and dyslipidaemia are more pronounced than with most alternatives. Baseline and ongoing weight, glucose, and lipid monitoring is essential, particularly in adolescents.
Efficacy is the counterweight
Olanzapine remains among the more effective agents for schizophrenia and acute mania, which is why it persists in use despite the metabolic profile. The trade-off should be explicit with patients.
Fluvoxamine raises levels substantially
CYP1A2 inhibition by fluvoxamine increases olanzapine concentrations, while carbamazepine lowers them. Smoking status also matters, as tobacco smoke induces CYP1A2.
Intramuscular form for acute agitation
10 mg IM with additional 5 to 10 mg doses to a daily maximum of 30 mg. A separate long-acting injection exists but carries its own post-injection monitoring requirements.
Licensed from age 13
Approved for adolescents with schizophrenia at 2.5 to 20 mg daily, though weight and metabolic monitoring matters even more in this group given the developmental stage.
Prescribing Information
Dosing & Administration
Schizophrenia – Adults:
- Initial: 5-10 mg daily
- Target: 10 mg daily
- Range: 10-20 mg daily
Schizophrenia – Adolescents:
- Initial: 2.5-5 mg daily
- Target: 10 mg daily
- Range: 2.5-20 mg daily
Bipolar I Disorder – Manic Episodes:
- Initial: 10-15 mg daily
- Range: 5-20 mg daily
Bipolar Maintenance:
- Range: 5-20 mg daily
Agitation (IM):
- Initial: 10 mg IM
- Additional doses: 5-10 mg IM (maximum 30 mg/day)
Indications
- Schizophrenia (adults and adolescents ≥13 years)
- Bipolar I disorder – manic or mixed episodes
- Bipolar disorder maintenance treatment
- Agitation associated with schizophrenia or bipolar I disorder
Contraindications
- Known hypersensitivity to olanzapine
Warnings & Precautions
- Boxed Warning: Increased mortality in elderly patients with dementia-related psychosis
- Metabolic changes: Weight gain, hyperglycemia, dyslipidemia
- Neuroleptic malignant syndrome: Discontinue if suspected
- Tardive dyskinesia: Risk increases with duration
- Orthostatic hypotension: Monitor blood pressure
- Seizures: Use caution in patients with seizure history
Drug Interactions
- CNS depressants: Enhanced sedation
- Anticholinergic drugs: Additive anticholinergic effects
- Dopamine agonists: Antagonistic effects
- Fluvoxamine: Increased olanzapine levels
- Carbamazepine: Decreased olanzapine levels
Adverse Reactions
Common (≥5%):
- Weight gain, somnolence, dizziness, increased appetite
Metabolic:
- Hyperglycemia, dyslipidemia, hyperprolactinemia
Special Populations
- Elderly: Increased mortality risk in dementia patients
- Pregnancy: Use only if benefits outweigh risks
- Hepatic impairment: Consider lower starting dose
- Adolescents: Monitor weight and metabolic parameters closely
Frequently Asked Questions
What is Olanzapine used for?
Olanzapine is an atypical antipsychotic indicated for schizophrenia, bipolar I disorder (manic or mixed episodes), and as maintenance treatment for bipolar disorder. It is also available as a long-acting injection and in combination with fluoxetine for treatment-resistant depression and bipolar depression.
What class of drug is Olanzapine?
Olanzapine is classified as: Atypical Antipsychotic.
Heaviest metabolic burden in the class?
Weight gain, hyperglycaemia, and dyslipidaemia are more pronounced than with most alternatives. Baseline and ongoing weight, glucose, and lipid monitoring is essential, particularly in adolescents.
Efficacy is the counterweight?
Olanzapine remains among the more effective agents for schizophrenia and acute mania, which is why it persists in use despite the metabolic profile. The trade-off should be explicit with patients.
Fluvoxamine raises levels substantially?
CYP1A2 inhibition by fluvoxamine increases olanzapine concentrations, while carbamazepine lowers them. Smoking status also matters, as tobacco smoke induces CYP1A2.
Intramuscular form for acute agitation?
10 mg IM with additional 5 to 10 mg doses to a daily maximum of 30 mg. A separate long-acting injection exists but carries its own post-injection monitoring requirements.
Source: FDA prescribing information (DailyMed)