TRIAVIL 4-50
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIAVIL 4-50 (TRIAVIL 4-50).
Amitriptyline is a tricyclic antidepressant that inhibits reuptake of serotonin and norepinephrine. Perphenazine is a typical antipsychotic that blocks dopamine D2 receptors.
| Metabolism | Amitriptyline is metabolized by CYP2D6, CYP2C19, and CYP3A4. Perphenazine is metabolized by CYP2D6 and CYP3A4. |
| Excretion | Renal: 50-60% as metabolites (amitriptyline and perphenazine), <5% unchanged; fecal: 20-30% (primarily perphenazine metabolites); biliary: minor route for perphenazine. |
| Half-life | Amitriptyline: 15-40 hours (mean 20-30 hours); perphenazine: 9-12 hours; clinical context: steady-state achieved within 5-7 days, dosing adjustments needed in hepatic impairment. |
| Protein binding | Amitriptyline: 90-95% bound to albumin and alpha-1-acid glycoprotein; perphenazine: 90-97% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Amitriptyline: 10-20 L/kg (widespread tissue distribution, high Vd indicates extensive extravascular binding); perphenazine: 10-20 L/kg (similar distribution pattern). |
| Bioavailability | Oral: amitriptyline 30-60% (first-pass metabolism, variability due to CYP2C19 and CYP2D6); perphenazine 20-40% (extensive first-pass metabolism). |
| Onset of Action | Oral: antidepressant effects of amitriptyline 2-4 weeks; antipsychotic effects of perphenazine 1-2 weeks; anxiolytic effects may occur within a few days. |
| Duration of Action | Amitriptyline: 24-48 hours (single dose), extended with repeated dosing; perphenazine: 12-24 hours; clinical notes: dosing usually 2-4 times daily; therapeutic effects persist after discontinuation due to slow elimination. |
One tablet (4 mg perphenazine / 50 mg amitriptyline) orally three times daily to four times daily. Maximum: 8 tablets per day.
| Dosage form | TABLET |
| Renal impairment | No specific dosing adjustment recommended; use caution in severe renal impairment (CrCl <10 mL/min) due to possible accumulation of amitriptyline metabolites. |
| Liver impairment | Child-Pugh A: No adjustment. Child-Pugh B: Reduce dose by 50%. Child-Pugh C: Contraindicated due to risk of hepatotoxicity and central nervous system effects. |
| Pediatric use | Not recommended for children under 12 years. For adolescents (12-18 years): 1/2 to 1 tablet (2-4 mg perphenazine/25-50 mg amitriptyline) twice daily, titrate slowly. Maximum: 6 tablets per day. |
| Geriatric use | Initiate with 1/2 tablet (2 mg perphenazine/25 mg amitriptyline) once or twice daily; increase gradually. Maximum: 4 tablets per day due to increased sensitivity to anticholinergic, sedative, and cardiovascular effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TRIAVIL 4-50 (TRIAVIL 4-50).
| Breastfeeding | Amitriptyline and perphenazine are excreted into breast milk. M/P ratio for amitriptyline is approximately 1.0; perphenazine M/P ratio not well established. Monitor infant for sedation, feeding issues, and extrapyramidal symptoms. Use only if benefit outweighs risk. |
| Teratogenic Risk | First trimester: Increased risk of congenital malformations (neural tube defects, cardiovascular anomalies) with combination containing amitriptyline and perphenazine. Second and third trimesters: Risk of neonatal withdrawal (irritability, feeding difficulties) and extrapyramidal symptoms. Perphenazine may cause fetal neurobehavioral effects. Both components cross placenta. |
■ FDA Black Box Warning
Increased risk of suicidal thinking and behavior in children, adolescents, and young adults with major depressive disorder and other psychiatric disorders.
| Serious Effects |
Concomitant use with MAOIs within 14 days, recent myocardial infarction, narrow-angle glaucoma, urinary retention, severe CNS depression, coadministration with cisapride or thioridazine.
| Precautions | May cause anticholinergic effects, sedation, orthostatic hypotension, QTc prolongation, extrapyramidal symptoms, neuroleptic malignant syndrome, tardive dyskinesia, and serotonin syndrome. |
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| Fetal Monitoring | Maternal: Serum levels of amitriptyline (if available), ECG for QT prolongation, liver and renal function, extrapyramidal symptoms, sedation. Fetal/neonatal: Ultrasound for congenital anomalies, neonatal monitoring for withdrawal, extrapyramidal signs, and cardiac function. |
| Fertility Effects | Both components may impair fertility. Amitriptyline can elevate prolactin levels, potentially causing menstrual irregularities and galactorrhea. Perphenazine is a potent dopamine antagonist, leading to hyperprolactinemia, anovulation, and reduced libido. Effects are reversible upon discontinuation. |