LOXITANE C
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LOXITANE C (LOXITANE C).
Loxapine, a dibenzoxazepine antipsychotic, acts primarily by blocking dopamine D2 receptors in the brain. It also exhibits affinity for serotonin 5-HT2A receptors, alpha-adrenergic, histaminergic, and muscarinic receptors, contributing to its antipsychotic and sedative effects.
| Metabolism | Primarily hepatic via cytochrome P450 enzymes (CYP1A2, CYP3A4, CYP2D6) to active metabolites including 7-hydroxy-loxapine, 8-hydroxy-loxapine, and amoxapine |
| Excretion | Approximately 70% renal (mainly as conjugated metabolites, <1% unchanged), 30% fecal via biliary excretion. |
| Half-life | Terminal elimination half-life is 4-8 hours (mean 6 hours). Clinical context: Requires multiple daily dosing; stable plasma levels achieved by second day. |
| Protein binding | 92-96% bound to albumin and alpha-1 acid glycoprotein. |
| Volume of Distribution | Vd: 1.5-2.5 L/kg (mean 2.0 L/kg). Extensive tissue distribution, including brain. |
| Bioavailability | Oral: 30-40% due to extensive first-pass metabolism; IM: 100%. |
| Onset of Action | Oral: 30-60 minutes for sedation; 2-3 weeks for full antipsychotic effect. |
| Duration of Action | Oral: 8-12 hours for sedation; prolonged antipsychotic effect persists for days after discontinuation. |
| Molecular Weight | 425.9 |
10 mg orally twice daily initially; may increase by 10 mg/day every 3–4 days; usual therapeutic range 60–100 mg/day; maximum 250 mg/day.
| Dosage form | CONCENTRATE |
| Renal impairment | No specific guidelines; use with caution in severe impairment (CrCl <10 mL/min) with reduced initial dose and slow titration. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended for use in children <16 years due to lack of safety data. |
| Geriatric use | Initial dose 5 mg orally twice daily; increase slowly by 5 mg/day; maximum 100 mg/day; monitor for orthostatic hypotension and QT prolongation. |
| 1st trimester | Limited human data; animal studies show risk. Use only if benefit outweighs risk. |
| 2nd trimester | Limited human data; potential for extrapyramidal symptoms in newborn. Use only if clearly needed. |
| 3rd trimester | Avoid in third trimester due to risk of neonatal extrapyramidal symptoms and withdrawal. |
Clinical note
Comprehensive clinical and safety monograph for LOXITANE C (LOXITANE C).
| Placental transfer | Crosses placenta; extent not well quantified. |
| Breastfeeding | Excreted into breast milk in small amounts; monitor infant for sedation and extrapyramidal effects. |
| 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, hyperglycemia and diabetes mellitus, orthostatic hypotension, leukopenia/neutropenia, agranulocytosis, QT prolongation, seizures, body temperature dysregulation, and dysphagia |
| Food/Dietary | Avoid grapefruit products as they may increase loxapine levels. Alcohol can exacerbate CNS depression and orthostatic hypotension; limit or avoid alcohol consumption. No other specific food restrictions are known. |
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| L3 |
| Teratogenic Risk | Pregnancy Category C. First trimester: Limited human data, animal studies show increased fetal resorptions and malformations at high doses. Second and third trimesters: Risk of extrapyramidal symptoms and/or withdrawal symptoms in neonates following maternal use. Not recommended unless benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and extrapyramidal symptoms. In neonates, observe for abnormal muscle movements, sedation, respiratory distress, and feeding difficulties. Consider fetal growth ultrasound if prolonged use. |
| Fertility Effects | May cause hyperprolactinemia leading to menstrual irregularities, galactorrhea, and decreased libido in females; reversible upon discontinuation. In males, potential for erectile dysfunction and gynecomastia. Animal studies: no direct impairment of fertility. |
| Clinical Pearls | LOXITANE C (loxapine) is a first-generation antipsychotic with high potency and a moderate side effect profile. Monitor for extrapyramidal symptoms (EPS), especially akathisia and dystonia, which may occur early in treatment. Use with caution in patients with dementia-related psychosis due to increased risk of cerebrovascular adverse events and mortality. Avoid concurrent use with drugs that prolong QTc interval. Titrate dose slowly to minimize orthostatic hypotension. Loxapine has a relatively short half-life (4-12 hours), requiring multiple daily doses for continuous effect. |
| Patient Advice | Take this medication exactly as prescribed; do not stop suddenly without consulting your doctor. · You may experience drowsiness, dizziness, or blurred vision; avoid driving or operating heavy machinery until you know how this medicine affects you. · Report any muscle stiffness, tremors, restlessness, or unusual movements to your healthcare provider immediately. · Avoid alcohol and grapefruit juice while taking this medication. · Rise slowly from sitting or lying positions to minimize lightheadedness. · Notify your doctor if you have a history of heart problems, seizures, or low blood pressure. · Do not take this medication if you are allergic to loxapine or any other antipsychotic. · Keep this medication out of reach of children and store at room temperature away from moisture and heat. |