Olanzapine Cristers (Olanzapine)

• Olanzapine is an atypical antipsychotic that modulates dopamine and serotonin pathways in psychotic and mood disorders.
• Schizophrenia: helps reduce hallucinations, delusions, and thought disorder, improving overall functioning.
• Bipolar disorder: stabilises mood during manic episodes and may aid in maintenance therapy, decreasing the frequency of mood swings.
• Acute psychosis: provides rapid symptom control, facilitating patient safety and cooperation with treatment.

• Olanzapine acts as an antagonist at dopamine D2 and serotonin 5‑HT2A receptors, with additional activity at histamine H1, muscarinic, and adrenergic receptors. This receptor profile reduces dopaminergic neurotransmission in mesolimbic pathways, alleviating psychotic symptoms, while serotonergic blockade contributes to mood‑stabilising effects.

Olanzapine may cause a range of adverse reactions that vary in frequency and severity.

Common Side Effects

• Weight gain: increased appetite leading to gradual weight increase.
• Sedation: drowsiness or feeling unusually tired.
• Dry mouth: reduced salivation causing discomfort.
• Constipation: slowed gastrointestinal motility.
• Dizziness: light‑headed sensation, especially when standing.
• Increased appetite: heightened desire for food.

Serious or Rare Side Effects

• Neuroleptic malignant syndrome: potentially life‑threatening reaction with fever and muscle rigidity.
• Agranulocytosis: severe drop in white blood cells increasing infection risk.
• Seizures: occurrence of convulsive episodes.
• Severe orthostatic hypotension: marked blood pressure drop upon standing.
• Hyperglycaemia: elevated blood sugar levels, possibly precipitating diabetes.
• Tardive dyskinesia: involuntary, repetitive movements, often of the face.

• Before initiating therapy, clinicians should evaluate patient‑specific risk factors and monitor ongoing safety.
• Monitor metabolic parameters: regularly check weight, glucose, and lipid levels.
• Assess cardiovascular status: evaluate blood pressure and heart rate, especially in patients with pre‑existing conditions.
• Avoid abrupt discontinuation: taper the dose to reduce withdrawal or relapse risk.
• Use caution in elderly with dementia: increased sensitivity to sedation and cognitive decline.
• Avoid use in patients with known hypersensitivity: discontinue if allergic reactions occur.
• Store at ambient temperature: keep in the original pack, protect from moisture.

Olanzapine can interact with other medicines, altering its effectiveness or safety profile.

Major Interactions (Avoid)

• CYP1A2 inhibitors (e.g., fluvoxamine): increase olanzapine plasma concentrations.
• CNS depressants (e.g., benzodiazepines): additive sedation and respiratory depression.
• Anticholinergic agents: may exacerbate anticholinergic burden and cognitive effects.

Moderate Interactions (Monitor Closely)

• CYP1A2 inducers (e.g., smoking, carbamazepine): reduce olanzapine levels, possibly diminishing efficacy.
• Lithium: combined use may heighten risk of neurotoxicity.
• Antihypertensives: olanzapine may enhance hypotensive effects, requiring blood pressure monitoring.