Loxapine

Inhalation/Respiratory
Acute agitation

Intramuscular
Acute psychosis

Oral
Psychoses

Should be taken with food.

Severe drug-induced CNS depression, coma (oral); current diagnosis or history of asthma, COPD, bronchospasm, or acute resp symptoms (inhalation).

Patient w/ decreased GI motility, paralytic ileus, urinary retention, BPH, xerostomia, glaucoma, or visual problems, low WBC count, risk of pneumonia, CV diseases, dehydration, cerebrovascular disease, hypovolaemia, Parkinson's disease; history of extrapyramidal symptoms, drug-induced leucopenia/neutropenia, risk factors for seizures (including those w/ history of seizures, head trauma, brain damage, alcoholism). Not indicated for dementia-related psychosis. Avoid abrupt withdrawal or dose reduction. Pregnancy and lactation.

Significant: Anticholinergic effects (e.g. constipation, xerostomia, blurred vision, urinary retention), CNS depression, oesophageal dysmotility/aspiration, extrapyramidal symptoms (e.g. pseudoparkinsonism, acute dystonic reactions, akathisia, tardive dyskinesia), risk of fall due to somnolence and motor or sensory instability, hyperprolactinaemia, neuroleptic malignant syndrome, pigmentary retinopathy, lenticular and corneal deposits, orthostatic hypotension, hypotension, syncope, impaired core body temp regulation.
Nervous: Sedation, agitation, confusion, dizziness, drowsiness, headache, insomnia, numbness, paraesthesia, seizure, slurred speech, tension, unsteady gait.
CV: ECG changes, oedema, HTN, tachycardia.
GI: Polydipsia, constipation, nausea, paralytic ileus, vomiting, xerostomia and dysgeusia (inhalation).
Resp: Dyspnoea, nasal congestion.
Hepatic: Hepatitis, increased serum ALT/AST, jaundice.
Genitourinary: Impotence, urinary retention, priapism.
Endocrine: Amenorrhoea, galactorrhoea, gynaecomastia, menstrual disease, wt gain, wt loss.
Musculoskeletal: Muscle twitching, muscle weakness.
Dermatologic: Flushing, alopecia, dermatitis, pruritus, seborrhoea, skin photosensitivity, rash.
Immunologic: Hypersensitivity (inhalation).
Others: Hyperpyrexia.
Potentially Fatal: Bronchospasm leading to resp distress and resp arrest. Blood dyscrasias (e.g. leucopenia, neutropenia, agranulocytosis).

IM/Inhalation/Respiratory/Parenteral/PO: C

This drug may cause somnolence, motor and sensory instability, if affected, do not drive or operate machinery.

Monitor hyperpyrexia, mental status changes, fever, muscle rigidity and autonomic instability, LFT, serum electrolyte level, menstrual changes, libido, abnormal involuntary movements or parkinsonian sign, tardive dyskinesia, visual changes. Monitor signs and symptoms of bronchospasm after oral inhalation admin.

Symptoms: Mild CNS depression, hypotension, resp depression, unconsciousness, severe extrapyramidal reactions, renal failure. Management: Symptomatic and supportive treatment. Empty stomach immediately by gastric lavage. Avoid emesis due to the possible aspiration of vomitus. Avoid analeptics (e.g. pentylenetetrazol), which may cause convulsions. Avoid epinephrine admin in patient w/ partial adrenergic blockade due to further lowering of BP. May give anticholinergic antiparkinsonian agent, diphenhydramine or anticonvulsant drugs to treat severe extrapyramidal symptoms. Extended haemodialysis may be useful in enhancing elimination.

Additive effect w/ other CNS or resp depressants (e.g. benzodiazepines, barbiturates, opioids) leading to excessive sedation and resp depression or resp failure. Loxapine may enhance the effect of anticholinergic drugs (e.g. aclidinium, cimetropium, ipratropium).

Additive CNS depressant effect w/ alcohol.

May give false positive result for phenylketonuria, amylase, uroporphyrins, urobilinogen.

Description:
Mechanism of Action: Loxapine is a tricyclic dibenzoxazepine-derivative antipsychotic agent. It blocks postsynaptic mesolimbic dopamine D₁ and D₂ receptors in the brain. It also inhibits serotonin 5-HT₂ receptors.
Onset: W/in 20-30 min (oral); 2 min (inhalation).
Duration: Approx 12 hr (oral).
Pharmacokinetics:
Absorption: Rapidly and completely absorbed. Time to peak plasma concentration: W/in 1-2 hr (oral); w/in 2 min (inhalation).
Distribution: Widely distributed in body tissues. Plasma protein binding: Approx 97% (inhalation).
Metabolism: Metabolised rapidly and extensively in the liver via hydroxylation into 8-OH-loxapine and 7-OH-loxapine metabolites, further metabolised via N-oxidation to form loxapine N-oxide metabolites, and via N-demethylation into amoxapine metabolite. Undergoes first-pass metabolism.
Excretion: Mainly via urine (40%, as conjugated metabolites); via faeces (10%, as unconjugated metabolites). Elimination half-life: 6-8 hr (inhalation). Oral: Biphasic: Initial: 5 hr; terminal: 19 hr.

Source: National Center for Biotechnology Information. PubChem Database. Loxapine, CID=3964, https://pubchem.ncbi.nlm.nih.gov/compound/Loxapine (accessed on Jan. 22, 2020)

Store between 15-30°C.

Thuốc chống loạn thần

N05AH01 - loxapine ; Belongs to the class of diazepines, oxazepines and thiazepines antipsychotics.

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