Olanzapine

Administration

  • Type: Antipsychotic, second generation
  • Dosage Forms: tablets, solution, suspension
  • Routes of Administration: oral, intramuscular
  • Common Trade Names: Zyprexa, Zydis

Adult Dosing

  • Acute agitation (associated with schizophrenia or bipolar disorder): Short-acting IM injection:
    • initial dose: 10 mg IM (consider lowering to 5 or 7.5 mg depending on clinical factors), additional dose of 10 mg IM maybe considered. Allowed 2 hours after the first dose and 4 hours after the second dose to evaluate response (maximum dose: 30 mg/day).
    • Special risk patients: consider lowering dose to 2.5 mg IM in patients who are debilitated, who have risk of hypotension or who maybe more pharmacodynamically sensitive to olanzapine.
  • Schizophrenia: Oral
    • Initial dose 5-10 mg once daily, increase to 10 mg daily by the first week, adjust by 5 mg daily at 1-week interval (maximum dose: 20 mg daily), maintenance dose: 10-20 mg daily.
    • Special risk patient: Initial dose: 5 mg once daily in patients who are debilitated, who have risk of hypotension or who maybe more pharmacodynamically sensitive to olanzapine.
  • Bipolar I (acute mixed or manic episode): Oral
    • Monotherapy: Initial dose: 10-15 mg once daily, increase by 5 mg daily with interval >24 hours, maintenance dose: 5-20 mg daily (maximum dose: 20 mg daily).
    • Combination therapy with lithium or valproate: Initial dose 10 mg daily (dose range: 5-20 mg daily)
  • Depression: Oral
    • Depression associated with bipolar disorder (in combination with fluoxetine): Initial dose: 5 mg once daily, adjust to dose range of 5-12.5 mg daily.

Pediatric Dosing

  • Schizophrenia: Adolescent ≥13 years: Oral: Initial dose: 2.5-5 mg once daily, adjust by 2.5-5 mg daily to target dose of 10 mg daily (dose range: 2.5-20 mg daily).
  • Bipolar I (acute or mixed manic episode): Adolescent ≥13 years: Oral: Initial dose: 2.5-5 mg once daily, adjust by 2.5-5 mg daily to target dose of 10 mg daily (dose range: 2.5-20 mg daily).
  • Depression associated with bipolar I disorder (in combination with fluoxetine: Children and adolescent 10 to 17 years: Oral: Initial dose: 2.5 mg once daily in the evening, adjust if needed, safety for dose >12 mg daily of olanzapine and >50 mg daily of fluoxetine has not been studied.

Special Populations

Renal Dosing

  • No dosage adjustment is necessary, not removed by dialysis.

Hepatic Dosing

  • Use with caution, in combination with fluoxetine, initial dose of olanzapine should not exceed 2.5-5 mg daily.

Contraindications

  • Allergy to class/drug

Adverse Reactions

Serious

  • Orthostatic hypotension (3%-20%)
  • Extrapyramidal reaction
  • Akathisia
  • Parkinsonian-like syndrome
  • Increase serum prolactin
  • Increase serum AST, ALT, GGT and bilirubin
  • Accidental injury
  • Personality disorder

Common

  • Drowsiness
  • Dizziness
  • Insomnia
  • Weight gain
  • Increase appetite
  • Xerostomia
  • Constipation
  • Dyspepsia
  • Weakness
  • Abnormal gait
  • Increase uric acid
  • Bruise
  • Tremor
  • Limb pain
  • Back pain
  • Arthralgia
  • Rhinitis

Pharmacology

  • Half-life: Oral and short-acting IM: children 10 to 18 years ~37 hours, adult ~30 hours, 1.5 times greater in elderly.
  • Metabolism: Liver: CYP1A2, CYP2D6, 40% removed via first pass metabolism
  • Excretion: Urine (~70%), feces (30%)

Mechanism of Action

  • Potent antagonism of serotonin 5-HT2A and 5T2C, Dopamine1-4, histamine H1 and α1-adrenergic recepter

Comments

See Also

References