Olanzapine is an atypical (second-generation) antipsychotic medication. It is a thienobenzodiazepine derivative that acts as a multi-receptor antagonist, primarily at dopamine D2 and serotonin 5-HT2A receptors. It is widely used in the Indian market for the management of schizophrenia, bipolar disorder, and as an antiemetic adjunct in chemotherapy. The 5mg strength is a common initiation and maintenance dose.
Adult: Schizophrenia/Bipolar Mania: Initial dose 5-10 mg once daily. Target range 10-15 mg/day. Maximum: 20 mg/day. CINV (adjunct): 10 mg orally on days 1-4 of chemotherapy.
Note: Administer once daily, with or without food, preferably in the evening due to sedative effects. Tablet should be swallowed whole with water. For patients with difficulty swallowing, the tablet can be dispersed in water, orange juice, apple juice, milk, or coffee immediately before administration.
Olanzapine exerts its therapeutic effects through a broad antagonistic activity at multiple neurotransmitter receptors in the central nervous system. Its atypical profile is attributed to a higher serotonin 5-HT2A than dopamine D2 receptor blockade ratio in the mesolimbic pathway.
Pregnancy: Pregnancy Category C (US FDA). Data in humans is limited. Use only if potential benefit justifies potential fetal risk. Neonates exposed in the 3rd trimester are at risk for extrapyramidal symptoms and withdrawal. Register with the Indian pregnancy registry if possible.
Driving: May impair alertness, judgment, and motor coordination, especially during initial treatment and dose adjustments. Patients should be cautioned against driving or operating heavy machinery until their individual response is known.
| Carbamazepine, Phenytoin, Rifampicin | Induce CYP1A2, reducing olanzapine plasma levels by up to 50%. Dose increase of olanzapine may be needed. | Major |
| Fluvoxamine, Ciprofloxacin | Potent CYP1A2 inhibitors, increase olanzapine plasma levels significantly (by 50-100%). Reduce olanzapine dose. | Major |
| Benzodiazepines (e.g., Lorazepam, Clonazepam) | Potentiation of sedative effects and risk of respiratory depression, especially with parenteral administration. | Moderate |
| Antihypertensives | Enhanced hypotensive effect, risk of orthostasis. | Moderate |
| Levodopa, Dopamine Agonists | Olanzapine antagonizes dopamine receptors, reducing efficacy of these drugs. | Moderate |
| Alcohol | Increased central nervous system depression (sedation, impaired judgment, psychomotor skills). | Major |
Same composition (Olanzapine (5mg)), different brands: