Adult: In patients with schizophrenia or bipolar disorder: As 4.5 mg or 9.1 mg inhalation powder in single-dose inhaler: Initially, 9.1 mg as a single dose. If required, a 2nd dose may be administered after 2 hours; no more than 2 doses should be given. Use the 4.5 mg dose if a lower dose is more appropriate or if the higher dose was not previously tolerated. Alternative recommendation: As 10 mg inhalation powder in single-dose inhaler: Administer only a single dose of 10 mg within a 24-hour period. Dosage recommendations may vary among countries and between individual products (refer to specific product guidelines).
Oral Schizophrenia
Adult: Initially, 10 mg bid (or up to 50 mg daily in patients with severe symptoms). Increase the dose over the 1st 7-10 days of therapy until with effective symptom control. Usual therapeutic dose range: 60-100 mg daily (Max: 250 mg daily). Maintenance therapy: Use the lowest effective dose compatible with symptom control (usual dose range: 20-60 mg daily). Daily doses are given in 2-4 divided doses and should be individually adjusted according to patient's requirements and response.
Administration
Should be taken with food.
Contraindications
Oral: Comatose states or severe drug-induced CNS depression. Inhalation: Current or history of asthma, COPD, or other lung disease associated with bronchospasm; acute respiratory signs and symptoms (e.g. wheezing).
Special Precautions
Patient with cardiovascular or cerebrovascular disease, conditions predisposing to hypotension (e.g. hypovolaemia, dehydration); risk factors for seizures (including history of seizure disorders, head trauma, brain damage, alcoholism); decreased gastrointestinal motility, paralytic ileus, BPH, urinary retention, xerostomia, visual problems, glaucoma; preexisting low WBC, history of drug-induced leucopenia/neutropenia; known history of extrapyramidal symptoms; risk factors for hypoventilation or aspiration pneumonia. Not approved for the treatment of dementia-related psychosis. Avoid abrupt withdrawal. Elderly. Pregnancy and lactation.
Adverse Reactions
Significant: CNS depression; extrapyramidal symptoms (e.g. pseudoparkinsonism, acute dystonic reactions, akathisia, tardive dyskinesia); seizures; anticholinergic effects (e.g. blurred vision, constipation, xerostomia, urinary retention); oesophageal dysmotility and aspiration; hypotension, syncope, orthostatic hypotension; increased risk for falls (caused by somnolence, motor or sensory instability, and orthostatic hypotension); hyperprolactinaemia; ocular effects such as lenticular and corneal deposits, pigmentary retinopathy (prolonged use); impaired core body temperature regulation. Cardiac disorders: Tachycardia, ECG changes (oral). Gastrointestinal disorders: Nausea, vomiting (oral); dysgeusia, throat irritation (inhalation). General disorders and administration site conditions: Hyperpyrexia (oral); fatigue (inhalation). Investigations: Elevated SGOT or SGPT, weight gain, weight loss (oral). Musculoskeletal and connective tissue disorders: Muscle twitching (oral). Nervous system disorders: Dizziness, lightheadedness, headache, slurred speech, paraesthesia (oral). Psychiatric disorders: Insomnia, agitation, tension, confusion (oral). Respiratory, thoracic and mediastinal disorders: Dyspnoea. Skin and subcutaneous tissue disorders: Dermatitis, pruritus, rash, alopecia, seborrhoea, facial oedema (oral). Vascular disorders: Hypertension (oral). Potentially Fatal: Neuroleptic malignant syndrome, blood dyscrasias (e.g. leucopenia, neutropenia, agranulocytosis); bronchospasm that may lead to respiratory arrest or distress, particularly in patients with lung disease (inhalation).
This drug may cause dizziness, somnolence or sedation, if affected, do not drive or operate machinery. Avoid strenuous exercise or activities, heat exposure, and dehydration during treatment.
Monitoring Parameters
Evaluate mental status, alertness, adherence (every visit); fall risk (as clinically indicated); history of metabolic syndrome (annually). Monitor CBC, electrolyte levels, renal and liver function, TSH, blood pressure, temperature, pulse rate (as clinically indicated); weight, height, and BMI (every visit for the 1st 6 months, then quarterly). Obtain prolactin level (if symptoms are reported); fasting blood glucose or HBA1c, lipid panel (4 months after treatment initiation and annually; check more frequently than annually if abnormal). Perform ocular examination as clinically indicated. Assess for extrapyramidal symptoms (every visit, 4 weeks after starting treatment, every dose changes, and annually); tardive dyskinesia (every visit and annually); signs of depression, and NMS (e.g. hyperpyrexia, altered mental status, muscle rigidity, autonomic instability). Inhalation: Observe for signs and symptoms of bronchospasm during the 1st hour of administration.
Overdosage
Symptoms: Mild CNS depression, profound hypotension, respiratory depression, unconsciousness, extrapyramidal symptoms, convulsive seizures, and renal failure. Management: Symptomatic and supportive treatment. Perform gastric lavage as soon as possible. May administer norepinephrine or phenylephrine for severe hypotension. Treat severe extrapyramidal reactions using anticholinergic antiparkinsonian agents or diphenhydramine. May initiate anticonvulsant therapy as indicated. Administration of IV fluids and oxygen may also be added.
Drug Interactions
Concomitant use with other CNS depressants (e.g. benzodiazepines, phenothiazines, TCAs, barbiturates, opioid analgesics, general anaesthetics, muscle relaxants) may increase the risk of respiratory depression, profound sedation, hypotension, and syncope. Increased risk of seizures with agents that are known to lower seizure threshold (e.g. phenothiazines, butyrophenones, clozapine, TCAs, SSRIs, tramadol, mefloquine). Co-administration with other anticholinergic drugs may increase the risk of anticholinergic adverse reactions, including glaucoma exacerbation and urinary retention. Loxapine inhibits the vasopressor effect of epinephrine, which may result in worsening of hypotension.
Food Interaction
Increased risk of CNS depression with alcohol.
Lab Interference
May give false positive result for phenylketonuria, amylase, uroporphyrins, urobilinogen tests.
Action
Description: Mechanism of Action: Loxapine is a dibenzoxazepine antipsychotic agent. Its mechanism of action is not yet established, but it is proposed to be mediated through high affinity antagonism of dopamine D2 receptors and serotonin 5-HT2A receptors. Loxapine also binds to noradrenergic, histaminergic, and cholinergic receptors. Onset: Agitation: Within 30 minutes (oral); within 10 minutes (inhalation). Schizophrenia: Within 1-2 weeks (oral). Duration: Approx 12 hours (oral). Pharmacokinetics: Absorption: Rapidly and completely absorbed after oral and inhalation administration. Bioavailability: 91% (inhalation). Time to peak plasma concentration: Within 1-2 hours (oral); within 2 minutes (inhalation). Distribution: Plasma protein binding: Approx 97% (inhalation). Metabolism: Rapidly and extensively metabolised in the liver into glucuronide conjugates. Excretion: Mainly via urine (as conjugated metabolites); faeces (as unconjugated metabolites). Elimination half-life: Oral (biphasic): 5 hours (initial); 19 hours (terminal). Inhalation: 6-8 hours.
Chemical Structure
Loxapine Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 3964, Loxapine. https://pubchem.ncbi.nlm.nih.gov/compound/Loxapine. Accessed Apr. 29, 2025.
Storage
Cap: Store between 20-25°C. Inhalation powder in single-dose inhaler: Store between 15-30°C. Keep the inhaler in the original pouch until ready for use to protect from light and moisture.
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