Loxapine

Evidence Level: L5

Predicted Indications: 9

Loxapine

Pharmacist Assessment Report

Loxapine: Retinal dystrophy with or without extraocular anomalies

One-Sentence Summary

Loxapine is a first-generation antipsychotic originally used for schizophrenia, bipolar disorder and major affective disorder. Because bipolar disorder is already a listed original indication, this is better described as a confirmation of an existing use than as true repurposing.

Quick Overview

Item	Content
Original Indication	Not recorded in the local data
Predicted New Indication	Retinal dystrophy with or without extraocular anomalies
TxGNN Prediction Score	0.9995
Evidence Level	L5 (provisional; see note below)
India Market Status	Listed in a compiled Indian medicine price dataset (at least 20) – CDSCO approval status is not included in this data
Number of Listed Products	at least 20
Recommended Decision	Proceed with Guardrails

Note on the evidence level: No clinical trials were supplied in the data compiled for this report. The L1 grade rests on the literature, which describes two Phase 3 randomised controlled trials of inhaled loxapine, and on regulatory approval of that formulation in the USA and EU. The primary trial publications should be verified before the grade is finalised.

Why is This Prediction Reasonable?

Detailed mechanism of action data is not available in the compiled data. Loxapine is a dibenzoxazepine antipsychotic. It is known to block dopamine D2 and serotonin 5-HT2A receptors, which is the pharmacology used to control mania and agitation.

Mania and schizophrenia share psychotic and agitated features that respond to dopamine antagonism. Bipolar disorder is already among loxapine’s original indications. An inhaled formulation (Adasuve) is approved in the USA and EU for acute agitation associated with bipolar I disorder or schizophrenia, and the literature supports this use. The prediction is therefore mechanistically sound, though it largely restates existing knowledge.

Literature Evidence

PMID	Year	Type	Journal	Key Findings
31496709	2019	Review	Neuropsychiatr Dis Treat	Safety, efficacy and patient acceptability of inhaled loxapine for acute agitation in schizophrenia or bipolar I disorder
27121764	2016	Review	Curr Med Res Opin	Inhaled loxapine for urgent treatment of acute agitation; rapid onset
22226343	2012	Review of 2 Phase III RCTs	Int J Clin Pract	Effect sizes of inhaled loxapine from two Phase III randomised controlled trials
23740380	2013	Review	CNS Drugs	Inhalation powder reaches peak plasma levels in a median of 2 minutes; two randomised, double-blind, placebo-controlled trials reviewed
27151529	2016	Systematic review and meta-analysis	Hum Psychopharmacol	Short-term pharmacological interventions for agitation in schizophrenia or bipolar disorder
33460070	2020	Review	Acta Psychiatr Scand	Evidence-based options for managing a manic episode, including choice of mood stabiliser and antipsychotic
38301034	2024	Review	Prim Care Companion CNS Disord	Alternative approaches to acute agitation in schizophrenia and bipolar disorder
37581475	2023	Review	Expert Opin Pharmacother	Improving pharmacotherapy of agitation associated with bipolar disorder
35913401	2022	Review	Expert Rev Neurother	Fifty years of experience with loxapine for rapid non-coercive tranquilisation
28208695	2017	Clinical review	Int J Mol Sci	Efficacy and tolerability of inhaled loxapine in acute agitation

India Market Information

Authorization Number	Product Name	Dosage Form	Approved Indication
123711	Loxapax 10mg Tablet	Strip of 10 tablets	Not stated in the licence record
128565	Loxafly 25mg Tablet	Strip of 10 tablets	Not stated in the licence record
130404	Loxip 10mg Capsule	Strip of 10 capsules	Not stated in the licence record
124529	Loxapac 10mg Capsule (Pfizer Ltd)	Strip of 10 capsules	Not stated in the licence record
123805	Loxapax Syrup	Bottle of 60 ml syrup	Not stated in the licence record

A total of 20 single-ingredient licences are valid, in tablet, capsule, syrup and drop forms.

Safety Considerations

Drug Interactions: 102 interactions were recorded. Major ones include bupropion, morphine and potassium citrate. Moderate ones include anticholinergic agents (atropine, hyoscyamine, glycopyrronium, dicyclomine, trospium), loperamide, epinephrine, dronabinol, nabilone and lorcaserin.
Formulation-specific guardrails (from the literature): the inhaled formulation carries a bronchospasm risk and requires restriction to controlled settings, with exclusion of patients with asthma or COPD. Sedation, extrapyramidal symptoms and QT effects also need attention.

Package insert warnings for the Indian products were not available and should be consulted.

Conclusion and Next Steps

Decision: Proceed with Guardrails

Rationale: Loxapine’s D2/5-HT2A antagonism fits the treatment of mania and agitation, and bipolar disorder is already a labelled original indication. The literature, including reviews of two Phase III trials of inhaled loxapine, supports use in acute agitation. However, no trials were supplied, and the safety burden is substantial.

To proceed, the following is needed:

Verification of the primary Phase 3 RCT publications to confirm the L1 grade
Package insert warnings and contraindications from the Indian product labels
Detailed mechanism of action data
Confirmation of which formulations are actually available in India, since inhaled loxapine is not among the listed products
A safety monitoring plan covering the large interaction burden, bronchospasm risk, sedation, extrapyramidal symptoms and QT effects

Other predictions (all Hold): The nine other predicted indications are retinal dystrophy, hydranencephaly, X-linked myopia (three entries), congenital disorder of glycosylation, Charcot-Marie-Tooth type 1G, perisylvian polymicrogyria and atypical glycine encephalopathy. For the myopia entries, D2 antagonism is expected to be unhelpful or counterproductive.

Disclaimer

This content is for research purposes only and does not constitute medical advice. Clinical validation is required before any clinical application.