Nurses Compass
Drug Guide
Loxapine
Classification
Therapeutic: Antipsychotic, Neuroleptic
Pharmacological: Phenothiazine derivative, Typical antipsychotic
FDA Approved Indications
- Acute treatment of agitation associated with schizophrenia or bipolar disorder
Mechanism of Action
Loxapine works by blocking dopamine D2 receptors and serotonin receptors in the brain, which helps to restore the balance of neurotransmitters and reduce symptoms of psychosis and agitation.
Dosage and Administration
Adult: Administer via inhalation using the pulmonary delivery system at a dose determined by clinical response; typically 10 mg inhaled once for agitation, with repeat doses if necessary after 2 hours, not to exceed 30 mg per 24 hours.
Pediatric: Not approved for use in children.
Geriatric: Use with caution; start at lower end of dosing spectrum due to increased sensitivity.
Renal Impairment: Adjust dosing based on clinical response; specific guidelines are limited.
Hepatic Impairment: Use with caution; hepatic function may affect drug metabolism.
Pharmacokinetics
Absorption: Rapid onset with inhalation, peak plasma levels achieved within minutes.
Distribution: Widely distributed in tissues, crosses the blood-brain barrier.
Metabolism: Primarily metabolized in the liver via CYP1A2 and CYP2D6 pathways.
Excretion: Excreted mainly via the urine, with some fecal elimination.
Half Life: Approximately 7 to 35 hours, depending on the individual and metabolic factors.
Contraindications
- Known hypersensitivity to loxapine or other phenothiazines
- History of asthma or other respiratory diseases involving bronchospasm
Precautions
- Use with caution in patients with cardiovascular disease, CNS depression, or seizure disorders; monitor respiratory function during administration.
Adverse Reactions - Common
- Drowsiness (Frequent)
- Dizziness (Frequent)
- Dry mouth (Frequent)
- Dystonia or extrapyramidal symptoms (Less common)
Adverse Reactions - Serious
- Respiratory depression or bronchospasm (Rare)
- QT prolongation, arrhythmias (Rare)
- Neuroleptic malignant syndrome (Rare)
Drug-Drug Interactions
- CNS depressants, other QT-prolonging agents, anticholinergic drugs
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor respiratory status closely during and after inhalation; observe for extrapyramidal symptoms and signs of neuroleptic malignant syndrome.
Diagnoses:
- Risk for respiratory depression
- Impaired physical mobility due to extrapyramidal side effects
Implementation: Administer inhalation therapy as prescribed; monitor for adverse effects; educate patient on proper inhalation technique.
Evaluation: Assess effectiveness in reducing agitation; monitor for adverse reactions and side effects.
Patient/Family Teaching
- Instruct patient on proper use of inhaler device.
- Report any breathing difficulties immediately.
- Educate about common side effects and when to seek medical attention.
Special Considerations
Black Box Warnings:
- Risk of serious respiratory depression and bronchospasm, which can be fatal.
- Likely to cause sedation and impair ability to perform tasks requiring alertness.
Genetic Factors: Metabolism via CYP1A2; smoking cessation may alter drug levels.
Lab Test Interference: None significant.
Overdose Management
Signs/Symptoms: Severe respiratory depression, hypotension, sedation, extrapyramidal symptoms, coma.
Treatment: Supportive care with airway management, oxygen therapy, monitoring vital signs; in severe cases, administering flumazenil or other specific antagonists is not recommended; consult poison control.
Storage and Handling
Storage: Store at room temperature away from moisture, heat, and light.
Stability: Stable as per manufacturer guidelines.