Olanzepine

Chemical

Thienobenzodiazepine → 2nd gen antipsychotic (ATYPICAL)

Use

  1. Schizophrenia
  2. Bipolar
  3. Resistant depression
  4. Delirium in ICU

Presentation

Tablets

Depot injection

Vial → 10mg for reconstitution

Dose

5 – 10mg/day

Route

PO/IM/IV

Onset

PO 5hrs

IM 15mins

MoA (mechanism)

  • Unknown
  • Dopamine & serotonin antagonism
  • Also antagonises α1, M1 – 5 & H1 receptors (side effects)

PD

CNS – relieves +ve & -ve symptoms of schizophrenia

PK

A

60% OBA

Extensive 1st pass

D

VD 1L

93% PPB

M

CYP450

Glucuronidation & oxidation

E

Metabolites in urine

t ½ B 20 – 60hrs

Adverse Effects

  • Hypotension
  • Weight gain
  • Fatigue
  • Dry mouth
  • Akathisia

Drug interactions: CYP1A2 inducers (alcohol, carbamazepine) = ↑clearance

Classical & Atypical Antipsychotics

Classic

D2 receptor blockade

Extrapyramidal S/E

2° strong D2 block

Effective for +ve symptoms

Atypical

Serotonin, D4 & D2 (weak)

Receptor blockade

Weak D2 blockade ∴ less incidence of EPSE

Effective for +ve & -ve symptoms