Olanzapina Azevedos (Olanzapine)

Olanzapine is indicated for psychiatric conditions that involve dopamine and serotonin dysregulation.

• Schizophrenia: reduces psychotic symptoms such as delusions and hallucinations.
• Bipolar I disorder (manic episodes): helps control mood swings and acute manic symptoms.
• Maintenance therapy for bipolar disorder: supports long‑term mood stabilization.
• Adjunctive treatment in major depressive disorder with psychotic features: enhances antidepressant response when combined with other agents.
• Off‑label use in anxiety disorders: may be prescribed when other treatments are insufficient, though evidence is limited.

• Olanzapine acts as an antagonist at multiple neurotransmitter receptors, including dopamine D2, serotonin 5‑HT2A/2C, histamine H1, and muscarinic receptors. By blocking dopamine and serotonin pathways, it reduces psychotic and mood‑stabilizing symptoms, while its antihistaminic and anticholinergic activity contributes to sedation and metabolic effects.

Olanzapine may cause a range of adverse reactions, from mild to potentially serious.

Common Side Effects

• Weight gain: increased appetite and caloric intake.
• Sedation: drowsiness or feeling of being overly sleepy.
• Dry mouth: reduced salivation.
• Constipation: slowed gastrointestinal motility.
• Elevated triglycerides: changes in blood lipid profile.
• Blurred vision: temporary visual disturbances.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: high fever, muscle rigidity, autonomic instability.
• Hyperglycaemia: significant rise in blood glucose levels, potentially leading to diabetes.
• Tardive dyskinesia: involuntary, repetitive movements, especially of the face.
• Seizures: increased risk of convulsive episodes.
• Severe orthostatic hypotension: marked drop in blood pressure upon standing.
• Agranulocytosis: dangerously low white‑blood cell count.

When prescribing Olanzapine, clinicians should consider several safety aspects.

• Metabolic monitoring: regularly assess weight, fasting glucose, and lipid profile.
• Cardiovascular assessment: monitor blood pressure and heart rate, especially during treatment initiation.
• Hepatic function: evaluate liver enzymes before and during therapy.
• Elderly patients: use lower doses and monitor for increased sedation and falls.
• Pregnancy and lactation: weigh potential benefits against risks; use only if clearly needed.
• Store at ambient temperature: keep in original container, protect from moisture and direct sunlight.

Olanzapine can interact with a variety of medications, affecting its efficacy and safety.

Major Interactions (Avoid)

• Strong CYP1A2 inhibitors (e.g., fluvoxamine): may increase olanzapine plasma levels, raising toxicity risk.
• CNS depressants (e.g., benzodiazepines, opioids): additive sedation and respiratory depression.
• Anticholinergic agents: heightened anticholinergic burden leading to constipation and urinary retention.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., carbamazepine, phenytoin): may reduce olanzapine concentrations, diminishing effectiveness.
• Smoking: induces CYP1A2, potentially lowering drug levels.
• Antihypertensive drugs: may enhance hypotensive effects, requiring blood pressure monitoring.