Olanzapine

Antipsychotic Drug

Drug class: Atypical Antipsychotic

Olanzapine (ZYPREXA)（中文：奧氮平）

Pronunciation

Olanzapine 10mg

Olanzapine 5mg

Common Strengths of Olanzapine Tablet

Olanzpine are available in the following strengths:

• 2.5 mg, 5 mg, 7.5 mg, 10 mg, 15 mg, 20 mg tablets

Drug Trade Names of Olanzapine Tablet

Zyprexa

Drug Usage

• Treatment of schizophrenia
• Acute treatment of manic or mixed episodes associated with bipolar disorder
• Maintenance treatment of bipolar disorder

Mechanism of Action

Olanzapine is a selective antagonist with high affinity binding to serotonin 5-HT2A/2C, dopamine D1 - 4, Histamine H1, and adrenergic α1 receptors.

Route of Administration

Oral

Dosages

• Schizophrenia: 5 - 10 mg once daily, with a target dose of 10 mg/day
• Bipolar mania: 10 - 15 mg once daily

No dosage adjustment is necessary for patients with renal impairment.

Side Effects

Frequency	Adverse reactions
Common	Weight gain and increased appetitie
	Drowsiness, sleepiness, or sedation
	Constipation
	Dizziness
Uncommon	Orthostatic hypotension (low blood pressure when standing up)
	Metabolic changes (high blood sugar, high cholesterol / triglycerides)
	Tardive dyskinesia (uncontrolled movements, especially of face and tongue)
	Neuroleptic malignant syndrome (high fever, muscle rigidity, confusion)
	Increased risk of death in elderly patients with dementia-related psychosis
	Higher risk of suicidal thoughts when taken with fluoxetine
	Blood disorders (low white blood cell count)
	Difficulty regulating body temperature
	Seizures
	Trouble swallowing

Pharmacokinetics

• Absorption: Well absorbed orally, reaching peak plasma concentrations in 5 - 8 hours
• Metabolism: Primarily hepatic via CYP1A2 and CYP2D6
• Elimination half-life: Approximately 33 hours
• Drug onset time and duration: Onset of action may be seen within 1 - 2 weeks, with full effects typically observed within 6 - 8 weeks.

Drug Precautions

Elderly Patients

Olanzapine is not approved for treating dementia-related psychosis due to an increased risk of death from cardiovascular or infectious causes. Elderly patients are also more sensitive to side effects like drowsiness, constipation, and dizziness, which can increase the risk of falls.

Teenagers

Adolescents may experience more pronounced side effects such as weight gain and increased cholesterol or triglyceride levels. Close monitoring is essential.

Pregnancy

Use with caution; potential risks to the fetus should be considered.

Breastfeeding

Not recommended; olanzapine is excreted in human milk.

Renal Impairment

No dosage adjustment necessary.

Olanzapine can impair your body's ability to regulate temperature. Avoid overheating and stay hydrated, especially during exercise or in hot weather.

Monitoring Requirements

• Weight
• Blood glucose
• Lipid profile (Cholesterol and Triglycerides)
• Signs of tardive dyskinesia (uncontrolled movements, especially of face and tongue)

Drug Interaction

Major Interactions

• CNS depressants
  • Benzodiazepines e.g. Diazepam, Lorazepam, Opioids, and Alcohol can enhance sedative effects, leading to an increased risk of severe drowsiness, and respiratory depression.
• QTc-Prolonging Medications
  • Combing it with other QTc-prolonging drugs (e.g. Citalopram, Domperidone, Azithromycin) can increase the risk of serious cardiac arrhythmias like Torsades de Pointes.
• Carbamazepine
  • This anticonvulsant can decrease the plasma concentration of olanzapine, potentially reducing its effectiveness.

FAQ

How Should I Take the Tablet?

Usually once daily with or without food.

What should I avoid while taking?

Avoid alcohol and activities requiring mental alertness until you know how Olanzapine affects you.

What Happens if I Miss a Dose?

Take the missed dose as soon as you remember unless it is almost time for your next dose. Do not double doses.