LOXITANE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LOXITANE (LOXITANE).
Loxapine is a typical antipsychotic that exerts its effects primarily by blocking dopamine D2 receptors in the mesolimbic pathway. It also has affinity for serotonin 5-HT2A, histamine H1, alpha1-adrenergic, and muscarinic receptors.
| Metabolism | Hepatic metabolism primarily via CYP1A2 and CYP3A4 isoenzymes, with minor contributions from CYP2D6. Metabolites include 8-hydroxyloxapine and loxapine N-oxide. |
| Excretion | Renal excretion accounts for 50-60% (primarily as metabolites, <1% unchanged). Fecal/biliary elimination accounts for 25-35% (via bile). |
| Half-life | 12-18 hours (terminal). Steady state achieved within 3-5 days; dosing adjustments for renal/hepatic impairment. |
| Protein binding | 92% (primarily to albumin and alpha-1-acid glycoprotein). |
| Volume of Distribution | 7-20 L/kg (extensive tissue distribution; large Vd indicates accumulation in tissues). |
| Bioavailability | Oral: 20-40% (extensive first-pass metabolism). IM: 100% (bioequivalent to IV). |
| Onset of Action | Oral: 30-60 minutes. IM: 15-30 minutes. |
| Duration of Action | 8-12 hours (oral); 6-8 hours (IM). Clinical effects may persist for up to 24 hours due to active metabolites. |
| Molecular Weight | 327.81 |
Oral: Initial 10 mg twice daily; may increase up to 250 mg/day in divided doses. IM: 12.5-50 mg every 4-6 hours.
| Dosage form | TABLET |
| Renal impairment | No specific dose adjustment guidelines available; use caution in severe renal impairment. |
| Liver impairment | No specific Child-Pugh based guidelines; use caution in severe hepatic impairment. |
| Pediatric use | Not recommended for children under 12 years; safety and efficacy not established. |
| Geriatric use | Start with lower doses (e.g., 5-10 mg/day oral) and titrate slowly due to increased sensitivity and risk of adverse effects. |
| 1st trimester | Limited human data; animal studies show fetal abnormalities at high doses. Avoid unless benefit outweighs risk. |
| 2nd trimester | Limited human data; risk of extrapyramidal symptoms in newborn. Use only if clearly needed. |
| 3rd trimester | Risk of neonatal extrapyramidal symptoms and withdrawal. Avoid near term. |
Clinical note
Comprehensive clinical and safety monograph for LOXITANE (LOXITANE).
| Placental transfer | Crosses placenta; achieves fetal concentrations 40-100% of maternal levels. |
| Breastfeeding | Loxapine is excreted into breast milk in small amounts. Monitor infant for sedation, poor feeding, and extrapyramidal symptoms. Use with caution, especially in preterm infants. |
| Lactation Rating |
■ FDA Black Box Warning
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Loxapine is not approved for the treatment of dementia-related psychosis.
| Serious Effects |
Hypersensitivity to loxapine or any componentSevere CNS depressionComatose states
| Precautions | Neuroleptic Malignant Syndrome (NMS), tardive dyskinesia, orthostatic hypotension, leukopenia/neutropenia, agranulocytosis, QT prolongation, seizures, hyperglycemia, dyslipidemia, weight gain, aspiration pneumonia (inhalation formulation). |
| Food/Dietary | Avoid grapefruit and grapefruit juice as they may increase loxapine levels via CYP3A4 inhibition. Also avoid caffeine-containing beverages if loxapine causes stimulation or anxiety. No specific food restrictions otherwise. |
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| L4 (Possibly Hazardous) |
| Teratogenic Risk | Loxapine is pregnancy category D. First trimester: human data limited, but known risk of teratogenic effects (e.g., CNS malformations) based on animal studies and other antipsychotics; avoid unless essential. Second/third trimesters: risk of extrapyramidal symptoms (EPS) and withdrawal in neonates (e.g., agitation, hypertonia, tremors, feeding difficulties). Use only if benefit outweighs risk. |
| Fetal Monitoring | Maternal: Monitor for EPS, sedation, weight gain, metabolic changes (glucose, lipids), orthostatic hypotension. Fetal/neonatal: Ultrasound for structural anomalies if first-trimester exposure; postnatal monitoring for EPS, withdrawal, sedation, and feeding difficulties. |
| Fertility Effects | Loxapine may increase prolactin levels, leading to hyperprolactinemia, which can cause galactorrhea, amenorrhea, anovulation, and reduced fertility in females. In males, possible erectile dysfunction, decreased libido, and impaired spermatogenesis. Effects are reversible upon dose reduction or discontinuation. |
| Clinical Pearls | LOXITANE (loxapine) is a first-generation antipsychotic used primarily for schizophrenia. It has potent D2, D3, D4, and 5-HT2A antagonism. Onset of action for acute agitation can be seen within 15-30 minutes intramuscularly. Monitor for extrapyramidal symptoms (EPS), tardive dyskinesia, and neuroleptic malignant syndrome. Loxapine is metabolized by CYP1A2 and CYP3A4; caution with inhibitors or inducers. The inhaled formulation (Adasuve) is for acute agitation and requires monitoring for bronchospasm, especially in patients with asthma or COPD. |
| Patient Advice | Take this medication exactly as prescribed; do not stop suddenly without consulting your doctor. · May cause drowsiness, dizziness, or blurred vision; avoid driving or operating machinery until you know how it affects you. · Stand up slowly from sitting or lying down to avoid dizziness or fainting. · Avoid alcohol and other CNS depressants as they can increase sedation. · Notify your doctor if you experience muscle stiffness, fever, confusion, irregular heartbeat, or uncontrolled movements. · Do not use the inhaled formulation if you have asthma, COPD, or other lung problems without discussing with your doctor. · Store at room temperature away from moisture and heat. |