TRIMEPRAZINE TARTRATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TRIMEPRAZINE TARTRATE (TRIMEPRAZINE TARTRATE).
Trimeprazine is a phenothiazine derivative that acts as an antagonist at histamine H1 receptors, dopamine D2 receptors, and muscarinic acetylcholine receptors, exerting antihistaminic, antiemetic, sedative, and anticholinergic effects.
| Metabolism | Hepatic metabolism via cytochrome P450 enzymes, primarily CYP2D6; metabolites include sulfoxides and N-demethylated derivatives. |
| Excretion | Primarily renal excretion of metabolites (approximately 70-80% as conjugated metabolites), with about 5-10% unchanged. Biliary/fecal elimination accounts for less than 20%. |
| Half-life | Terminal elimination half-life is approximately 3.5 to 4 hours in adults; may be prolonged in elderly or hepatic impairment, necessitating dose adjustment. |
| Protein binding | Approximately 90-95% bound to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Approximately 2.5-3.5 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: 25-40% due to extensive first-pass metabolism; IM: 75-85%; IV: 100%. |
| Onset of Action | Oral: 30-60 minutes; Intramuscular: 15-30 minutes; Intravenous: 5-10 minutes. |
| Duration of Action | Oral: 4-6 hours; IM/IV: 3-4 hours. Duration may be shorter in children and longer in elderly due to altered clearance. |
10-20 mg orally 3-4 times daily; maximum 100 mg/day.
| Dosage form | SYRUP |
| Renal impairment | GFR ≥50 mL/min: no adjustment; GFR 10-49 mL/min: administer 50% of usual dose; GFR <10 mL/min: avoid use. |
| Liver impairment | Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use. |
| Pediatric use | Children 2-12 years: 0.5-1 mg/kg/day orally in divided doses every 4-6 hours; maximum 40 mg/day. |
| Geriatric use | Initiate at 5 mg 3 times daily; increase cautiously to avoid sedation and hypotension; maximum 50 mg/day. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TRIMEPRAZINE TARTRATE (TRIMEPRAZINE TARTRATE).
| Breastfeeding | Excreted in breast milk; M/P ratio not determined. Use caution due to risk of infant sedation and respiratory depression. Consider risks versus benefits. |
| Teratogenic Risk | Limited human data; animal studies not conducted. First trimester: insufficient evidence to exclude risk. Second and third trimesters: potential for neonatal respiratory depression and hypotonia if used near term. Avoid in pregnancy unless clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to trimeprazine or other phenothiazines","CNS depression","Comatose states","Severe hypotension","QT prolongation or known history of arrhythmias","Concomitant use with monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOIs"]
| Precautions | ["May cause QT interval prolongation; use with caution in patients with cardiac disease or electrolyte disturbances.","May cause extrapyramidal symptoms, especially in elderly or debilitated patients.","May cause tardive dyskinesia with prolonged use.","May cause neuroleptic malignant syndrome (rare).","Sedation and dizziness may impair ability to drive or operate machinery.","May cause anticholinergic effects (dry mouth, urinary retention, constipation, blurred vision).","Use with caution in patients with glaucoma, prostate hypertrophy, or hepatic impairment."] |
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| Monitor maternal blood pressure, heart rate, and respiratory status. In third trimester, observe neonate for signs of withdrawal, respiratory depression, or hypotonia. |
| Fertility Effects | No specific data on fertility. Anticholinergic and antihistaminic effects may theoretically impact fertility. |