ETRAFON-FORTE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ETRAFON-FORTE (ETRAFON-FORTE).
ETRAFON-FORTE is a combination of perphenazine (a phenothiazine antipsychotic) and amitriptyline (a tricyclic antidepressant). Perphenazine blocks postsynaptic dopamine D2 receptors in the mesolimbic system. Amitriptyline inhibits reuptake of serotonin and norepinephrine, enhancing neurotransmission. Additionally, amitriptyline blocks histamine H1, muscarinic, and alpha-adrenergic receptors.
| Metabolism | Perphenazine is metabolized primarily by CYP2D6, with minor contributions from CYP3A4. Amitriptyline is metabolized by CYP2C19, CYP1A2, and CYP2D6 to nortriptyline. |
| Excretion | Primarily renal (approximately 70-80% as metabolites, <5% unchanged). Biliary/fecal elimination accounts for about 15-20% due to enterohepatic recirculation of metabolites. |
| Half-life | Terminal elimination half-life of perphenazine: 8-12 hours; amitriptyline: 13-36 hours (mean ~20 hours). Steady-state achieved in 3-7 days. Clinical context: twice-daily dosing maintains therapeutic levels. |
| Protein binding | Perphenazine: ~90% bound to albumin and alpha-1-acid glycoprotein. Amitriptyline: ~96% bound primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Perphenazine: 10-15 L/kg; amitriptyline: 15-20 L/kg. Large Vd indicates extensive tissue distribution, particularly in brain, liver, and lungs. |
| Bioavailability | Oral: Perphenazine 40-60% (first-pass metabolism); amitriptyline 45-60% (first-pass metabolism). IM: Perphenazine ~100%. |
| Onset of Action | Oral: 1-3 hours for perphenazine (antipsychotic effect); 2-6 hours for amitriptyline (antidepressant effect). Peak plasma concentrations at 2-4 hours (perphenazine) and 2-8 hours (amitriptyline). |
| Duration of Action | Perphenazine: 6-12 hours; amitriptyline: 24-72 hours for antidepressant effect. Clinical note: Therapeutic response in depression may take 1-4 weeks. Antipsychotic effects may be seen within days. |
| Molecular Weight | Perfluphenazine HCl: 438.0 Da; Amitriptyline HCl: 313.9 Da |
ETRAFON-FORTE (perphenazine 4 mg / amitriptyline 25 mg) oral tablets: 1 tablet three times daily or 1 tablet four times daily. Maximum daily dose: 4 tablets (perphenazine 16 mg / amitriptyline 100 mg).
| Dosage form | TABLET |
| Renal impairment | GFR 10-50 mL/min: reduce dose by 50% or increase dosing interval; GFR <10 mL/min: avoid use or reduce dose by 75%. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated. |
| Pediatric use | Not recommended in children under 12 years. Adolescents: initial dose perphenazine 2 mg / amitriptyline 10 mg orally three times daily, titrate based on response; maximum perphenazine 16 mg / amitriptyline 100 mg daily. |
| Geriatric use | Initial dose: perphenazine 1 mg / amitriptyline 10 mg orally twice daily; titrate slowly; monitor for anticholinergic effects, orthostatic hypotension, and sedation. Maximum daily dose: perphenazine 8 mg / amitriptyline 50 mg. |
| 1st trimester | Avoid in first trimester due to potential teratogenicity; animal studies show fetal abnormalities and human data suggest increased risk of congenital malformations. |
| 2nd trimester | Use only if potential benefit justifies risk; may cause neonatal respiratory depression, hypotonia, and withdrawal symptoms. |
| 3rd trimester | Avoid near term due to risks of neonatal respiratory depression, hypotonia, persistent pulmonary hypertension, and withdrawal symptoms. |
Clinical note
Comprehensive clinical and safety monograph for ETRAFON-FORTE (ETRAFON-FORTE).
| Placental transfer | Perfluphenazine (component) crosses placenta; amitriptyline (component) also crosses. Both reach fetal circulation. |
| Breastfeeding | Excreted into breast milk in low amounts; however, potential for serious adverse reactions in nursing infants (e.g., sedation, respiratory depression). Consider risk vs benefit; alternative agents preferred. |
■ FDA Black Box Warning
WARNING: Increased mortality in elderly patients with dementia-related psychosis. Antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults in short-term studies. Not approved for use in pediatric patients.
| Serious Effects |
Hypersensitivity to perfluphenazine, amitriptyline, or other phenothiazines/tricyclic antidepressantsConcomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of MAOI discontinuationSevere central nervous system depression (e.g., coma, brain damage)Narrow-angle glaucomaPregnancy (especially first trimester) and breastfeeding
| Precautions | Risk of extrapyramidal symptoms, tardive dyskinesia, and neuroleptic malignant syndrome due to perphenazine, Anticholinergic effects including urinary retention, constipation, and glaucoma exacerbation from amitriptyline, Cardiotoxicity: QTc prolongation, arrhythmias, and myocardial infarction risk, Avoid abrupt discontinuation to prevent withdrawal symptoms, May impair mental or physical abilities; caution with alcohol and CNS depressants, Hepatic impairment, renal impairment, and hypothyroidism require dose adjustment |
| Food/Dietary |
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| Lactation Rating | L4 (Possibly Hazardous) |
| Teratogenic Risk | FDA Pregnancy Category D. First trimester: association with congenital malformations (neural tube defects, cardiovascular anomalies). Third trimester: prolonged exposure may cause neonatal withdrawal (irritability, hypertonia) and persistent pulmonary hypertension. Avoid in pregnant women unless benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal blood pressure, weight, mental status; fetal ultrasound for congenital anomalies; neonatal monitoring for withdrawal syndrome and pulmonary hypertension post-delivery. |
| Fertility Effects | Amitriptyline: may decrease libido, impair erectile function; perphenazine: hyperprolactinemia causing menstrual irregularities, anovulation in women. Both may reduce fertility. |
| Avoid alcohol and tyramine-rich foods (e.g., aged cheese, cured meats, fermented products) due to additive CNS depression and risk of hypertensive crisis. Limit caffeine and nicotine. Grapefruit juice may increase amitriptyline levels. |
| Clinical Pearls | Contains perphenazine (a phenothiazine antipsychotic) and amitriptyline (a tricyclic antidepressant). Do not use in patients with recent MI, QT prolongation, or MAOI use within 14 days. Watch for extrapyramidal symptoms, tardive dyskinesia, anticholinergic effects, and orthostatic hypotension. Caution in elderly due to fall risk and cognitive impairment. Monitor EKG, liver function, CBC, and electrolyte levels. Rapid dose changes can cause neuroleptic malignant syndrome. |
| Patient Advice | Do not discontinue suddenly; taper under doctor's supervision. · May cause drowsiness or dizziness; avoid driving or operating heavy machinery until effects are known. · Avoid alcohol and other CNS depressants. · Report any signs of infection, fever, muscle stiffness, confusion, or irregular heartbeat immediately. · Use sunscreen and protective clothing; may increase sensitivity to sunlight. · Consult healthcare provider before taking other medications, especially anticholinergics, antihistamines, or MAOIs. |