Zyprexa (olanzapine) is a second-generation atypical antipsychotic medication indicated for the treatment of schizophrenia and bipolar I disorder. It functions by modulating dopamine and serotonin pathways in the brain, offering a refined mechanism of action compared to first-generation antipsychotics. Clinically, it is recognized for its efficacy in managing both positive and negative symptoms, as well as acute manic or mixed episodes. Its pharmacokinetic profile supports once-daily dosing, promoting adherence and consistent therapeutic levels.

Features

• Active ingredient: Olanzapine
• Available formulations: Oral tablets, orally disintegrating tablets (Zyprexa Zydis), and short-acting intramuscular injection
• Standard tablet strengths: 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg
• Half-life: Approximately 30 hours
• Metabolism: Hepatic, primarily via CYP1A2 and CYP2D6 isoenzymes
• Excretion: Urinary (57%) and fecal (30%)

Benefits

• Effective reduction of positive symptoms such as hallucinations and delusions in schizophrenia
• Management of negative symptoms including social withdrawal and affective flattening
• Rapid control of acute agitation and manic symptoms in bipolar disorder
• Lower incidence of extrapyramidal symptoms compared to typical antipsychotics
• Once-daily dosing supports treatment adherence and stable plasma concentrations
• Multiple formulations allow for individualized treatment plans across clinical settings

Common use

Zyprexa is primarily prescribed for the treatment of schizophrenia in adults and adolescents aged 13-17 years. It is also indicated for acute manic or mixed episodes associated with bipolar I disorder as monotherapy or adjunctive therapy with lithium or valproate in adults, and as monotherapy in adolescents aged 13-17 years. Additionally, it is used in combination with fluoxetine for treatment-resistant depression and depressive episodes associated with bipolar I disorder. Off-label uses may include behavioral symptoms of dementia (with caution due to black box warning), Tourette’s syndrome, and certain anxiety disorders, though these applications require careful risk-benefit analysis.

Dosage and direction

Dosage must be individualized based on clinical presentation, tolerability, and treatment response.

Schizophrenia (adults): Initial dose: 5-10 mg once daily. Target dose: 10-15 mg daily. Maximum: 20 mg/day.
Schizophrenia (adolescents 13-17): Initial dose: 2.5-5 mg once daily. Target dose: 10 mg daily. Maximum: 20 mg/day.
Bipolar mania (adults): Initial dose: 10-15 mg once daily. Adjust by 5 mg increments. Maintenance: 5-20 mg daily.
Bipolar mania (adolescents 13-17): Initial dose: 2.5-5 mg once daily. Target dose: 10 mg daily. Maximum: 20 mg/day.
Depression (with fluoxetine): Olanzapine: 2.5-20 mg; Fluoxetine: 20-50 mg.

Administration: May be taken with or without food. Orally disintegrating tablets should be placed on the tongue immediately after opening the blister.

Precautions

Zyprexa carries a black box warning for increased mortality in elderly patients with dementia-related psychosis. Use requires careful monitoring for metabolic changes including weight gain, hyperglycemia, and dyslipidemia. Regular assessment of BMI, blood glucose, and lipid profiles is recommended. Orthostatic hypotension may occur, particularly during initial dose titration. Neuroleptic malignant syndrome and tardive dyskinesia, though rare, represent serious potential adverse effects. Patients should be cautioned about impaired cognitive and motor performance, especially when operating machinery. Pregnancy category C: use only if potential benefit justifies potential risk to fetus.

Contraindications

Hypersensitivity to olanzapine or any component of the formulation. Concurrent use with other drugs known to cause QT prolongation may be contraindicated in patients with known QT prolongation or cardiac arrhythmias. Severe hepatic impairment may necessitate contraindication due to reduced clearance. Combination with fluoxetine is contraindicated in patients taking thioridazine or monoamine oxidase inhibitors.

Possible side effect

Very common (>10%): Somnolence, weight gain, increased appetite, dizziness
Common (1-10%): Orthostatic hypotension, peripheral edema, hyperprolactinemia, extrapyramidal symptoms, elevated liver enzymes, dry mouth, constipation
Uncommon (0.1-1%): QT prolongation, leukopenia, neutropenia, seizures, galactorrhea
Rare (<0.1%): Neuroleptic malignant syndrome, tardive dyskinesia, pancreatitis, allergic reactions
Metabolic effects: Significant weight gain (mean 2.5 kg after 10 weeks), hyperglycemia (including new-onset diabetes), dyslipidemia

Drug interaction

Strong CYP1A2 inhibitors (fluvoxamine): May increase olanzapine levels - reduce olanzapine dose by 50%
CYP1A2 inducers (carbamazepine, smoking): May decrease olanzapine levels - consider dose adjustment
Antihypertensives: Enhanced hypotensive effects
CNS depressants (alcohol, benzodiazepines): Additive sedation and cognitive impairment
Dopamine agonists: May diminish effectiveness
Drugs prolonging QT interval (antiarrhythmics, certain antibiotics): Additive risk of cardiac arrhythmias

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is close to the time of the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Doubling doses to make up for a missed dose is not recommended. Patients should be educated on maintaining consistent dosing intervals to ensure stable therapeutic levels.

Overdose

Symptoms may include drowsiness, slurred speech, tachycardia, hypotension, extrapyramidal symptoms, and agitation. In severe cases, respiratory depression, coma, or cardiac arrhythmias may occur. Management is supportive and symptomatic, including gastric lavage if presented early, activated charcoal, and close monitoring of cardiac and respiratory function. There is no specific antidote. Hemodialysis is unlikely to be effective due to high protein binding.

Storage

Store at controlled room temperature (15-30°C or 59-86°F). Protect from light and moisture. Keep in original container with tight closure. Orally disintegrating tablets should remain in blister packaging until immediately before use. Keep out of reach of children and pets. Do not use after expiration date printed on packaging.

Disclaimer

This information is for educational purposes only and does not constitute medical advice. Zyprexa is a prescription medication that should only be used under the supervision of a qualified healthcare professional. Individual response to medication may vary. Patients should not initiate, discontinue, or change dosage without consulting their prescribing physician. The full prescribing information including boxed warnings should be reviewed before administration.

Reviews

Clinical trials demonstrate Zyprexa’s efficacy with response rates of approximately 60-70% in schizophrenia and bipolar mania. Many clinicians report significant improvement in both positive and negative symptoms, particularly in treatment-resistant cases. However, reviews consistently note metabolic concerns as a significant treatment consideration. Patient-reported outcomes often mention improved reality testing and mood stabilization, though weight gain and sedation are frequently cited drawbacks. Long-term studies show maintained efficacy in relapse prevention with appropriate monitoring and adjunctive lifestyle interventions.