Loxapine Uses in Psychiatry
Loxapine is primarily indicated for the treatment of schizophrenia, with established efficacy in both newly hospitalized and chronically hospitalized acutely ill schizophrenic patients. 1
Primary Indications
- Schizophrenia: FDA-approved for treatment of schizophrenia in oral formulation 1
- Acute agitation: Inhaled loxapine is approved for acute treatment of mild-to-moderate agitation in adults with schizophrenia or bipolar disorder 2, 3
Efficacy Profile
Loxapine demonstrates efficacy comparable to other antipsychotics:
- Similar antipsychotic efficacy to both typical and atypical antipsychotics 4
- In adolescents with schizophrenia, loxapine was found to be superior to placebo but did not differ from haloperidol in effectiveness 5
- For acute agitation, inhaled loxapine shows rapid onset of action within 10 minutes of administration 3
Available Formulations
- Oral capsules: Standard formulation for maintenance treatment of schizophrenia 1
- Intramuscular injection: For acute management of agitation 2
- Inhaled powder (Adasuve®): Provides rapid onset of action (median time to maximum plasma concentration: 2 minutes) for acute agitation 3
Side Effect Profile
Loxapine's side effect profile is similar to typical antipsychotics, particularly at higher doses:
- Common side effects include extrapyramidal symptoms, sedation, and dysgeusia (with inhaled formulation) 2, 6
- At higher doses, side effect profile resembles typical antipsychotics 2
- Inhaled loxapine is contraindicated in patients with airways disease associated with bronchospasm or acute respiratory signs/symptoms 3
Treatment Considerations
When using loxapine:
- Allow 4-6 weeks at therapeutic doses before determining efficacy for schizophrenia 5
- For acute agitation, inhaled loxapine provides a non-invasive alternative to intramuscular injections with comparable onset of action 3
- Monitor for extrapyramidal symptoms, which occur at rates similar to typical antipsychotics 4
Important Cautions
- Inhaled loxapine requires screening for pulmonary disease before administration due to risk of bronchospasm 3
- Sedation is common, especially during early treatment stages 6
- Less common side effects include anticholinergic effects, hypotension, tachycardia, and potential precipitation of epileptic seizures 6
Loxapine represents an established antipsychotic option that, while not distinctly different from other antipsychotics in terms of overall efficacy, offers the advantage of multiple administration routes, including a rapid-acting inhaled formulation for acute situations.