Loxapine is a typical antipsychotic medication, used primarily in the treatment of schizophrenia. Trade names for loxapine taken by mouth include Loxapac and Loxitane; the inhalable form is approved as Adasuve. The drug is a member of the dibenzoxazepine class and structurally related to clozapine (which belongs to the chemically akin class of dibenzodiazepines). Several researchers have argued that loxapine may behave as an atypical antipsychotic.
Loxapine may be metabolized by N-demethylation to amoxapine, a tetracyclic antidepressant.
Therapeutic uses and dosages
The typical starting dosage is 10 mg twice daily; usual dose range 30â€"50 mg twice daily; maximum recommended dosage is 250 mg per day. The US Food and Drug Administration (FDA) has approved loxapine inhalation powder 10 mg (Adasuve, Alexza Pharmaceuticals) for the acute treatment of agitation associated with schizophrenia or bipolar I disorder in adults.
A brief review of loxapine found no conclusive evidence that it was particularly effective in patients with paranoid schizophrenia. A subsequent systematic review considered that the limited evidence did not indicate a clear difference in its effects from other antipsychotics.
Loxapine was one of five antipsychotics used in a study on the structure of neurons in parts of the brain thought to be involved in schizophrenia. Only loxapine was linked to the development of new connections between neurons.
Precautions
This drug is unrelated to the habit-forming benzodiazepines, and misuse is rare. The risks and side effect profile are comparable to other antipsychotics.
Side effects
Note: Percentages given after possible adverse effects refer to the incidence of said adverse effects, according to DrugPoint.
- Common side effects of loxapine (≥1% incidence) when inhaled include
- Taste sense altered (14%)
- Sedated (12%)
- Pharyngitis (3%)
Intense Sleeping (Highest Procentage) In Pill Form Blurred Speech (In Pill Form)
- Common side effects of orally-administered loxapine include
- Constipation
- Dry mouth
- Akathisia
- Dizziness
- Intense Sleeping (Highest Procentage) (In Pill Form)
- Blurred Speech (In Pill Form)
- Extrapyramidal disease (dose-dependent. At lower dosages its propensity for causing extrapyramidal side effects appears to be similar to that of atypical antipsychotics
- Blurred vision
- Urinary retention
- Somnolence (which appears to be moderate in severity compared to other antipsychotic drugs)
- Dyspnoea
- Nasal congestion
- Rare side effects include
- Paralytic ileus
- Agranulocytosis
- Leukopenia
- Thrombocytopenia
- Hepatocellular liver damage
- Neuroleptic malignant syndrome
- Seizure
- Tardive dyskinesia
- Stroke
- Transient ischaemic attack
- Death
Pharmacology
The data in the following table was obtained from the PDSP Ki database and they are for binding towards human cloned proteins (receptor and transporter) unless otherwise specified.
Synthesis
References
External links
- Product monograph from Medscape (free registration required).