API

Olanzapine (20mg)

Drug classification

Atypical antipsychotic; thienobenzodiazepine subclass.

Dosage form

Dispersible tablet containing 20 mg olanzapine.

API strength per dosage

Dose

Olanzapine dosing is individualized; typical adult starting dose for schizophrenia or bipolar disorder is 5–10 mg once daily, titrated as needed. Maximum recommended dose is generally 20 mg/day. Use lower initial doses in elderly or debilitated patients. Safety and efficacy in children under 13 years not established. Caution in hepatic impairment; no adjustment usually needed for renal impairment.

Mechanism of action

Olanzapine antagonizes dopamine D2 and serotonin 5-HT2A receptors in the brain, reducing dopaminergic and serotonergic neurotransmission. It also blocks histamine H1, muscarinic M1–M5, and adrenergic α1 receptors, contributing to its antipsychotic, mood-stabilizing, and sedative effects, as well as its side effect profile.

Indications

Treatment of SchizophreniaTreatment of Mania

Side effects

Dizziness Sleepiness Orthostatic hypotension sudden lowering of blood pressure on standing Dryness in mouth Weight gain Increased prolactin level in blood Constipation Muscle stiffness Restlessness Tremors

Pregnancy category

Olanzapine should be used during pregnancy only if benefits justify potential risks; limited human data, possible neonatal withdrawal or extrapyramidal symptoms reported.

Precautions

Monitor for sedation, weight gain, metabolic changes (glucose, lipids), extrapyramidal symptoms, tardive dyskinesia, orthostatic hypotension, QT prolongation, neuroleptic malignant syndrome, hepatic function, leukopenia, seizure risk, avoid abrupt discontinuation, caution in elderly, monitor for suicidal ideation, avoid alcohol, assess for drug interactions.

Contraindications

Hypersensitivity to olanzapine, known risk of narrow-angle glaucoma, patients with known galactose intolerance, lactase deficiency, or glucose-galactose malabsorption, history of drug-induced neutropenia or agranulocytosis.