TORECAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TORECAN (TORECAN).
TORECAN (thiethylperazine) is a phenothiazine derivative that acts primarily as a dopamine D2 receptor antagonist in the chemoreceptor trigger zone (CTZ) to exert antiemetic effects. It also possesses anticholinergic and antihistaminergic properties.
| Metabolism | Hepatic metabolism, primarily via CYP2D6 and other cytochrome P450 enzymes; undergoes sulfoxidation and N-demethylation. |
| Excretion | Primarily renal (60-70% as unchanged drug and metabolites); biliary/fecal (20-30%). |
| Half-life | Terminal elimination half-life: 6-8 hours. Clinical context: Allows twice-daily dosing; prolonged in renal impairment. |
| Protein binding | 60-70% bound to albumin. |
| Volume of Distribution | Vd: 3-5 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: 40-50% due to first-pass metabolism; IM: ~80%; IV: 100%. |
| Onset of Action | Oral: 30-60 minutes; IM: 15-30 minutes; IV: 5-10 minutes. |
| Duration of Action | 4-6 hours for antiemetic effect; clinical notes: Duration may be shorter with repeated dosing due to tachyphylaxis. |
10 mg orally or intramuscularly every 6 to 8 hours as needed for nausea and vomiting.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment recommended; caution in severe renal impairment (GFR <30 mL/min) due to risk of accumulation. |
| Liver impairment | Child-Pugh Class A: no adjustment; Class B: reduce dose by 50%; Class C: avoid use. |
| Pediatric use | 0.2 mg/kg orally or intramuscularly every 6 to 8 hours as needed; maximum 10 mg per dose. |
| Geriatric use | Initiate at lower end of dosing range (e.g., 5-10 mg every 8-12 hours) due to increased sensitivity and risk of anticholinergic effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TORECAN (TORECAN).
| Breastfeeding | TORECAN is excreted into human breast milk. The M/P ratio is unknown. Due to potential adverse effects in the nursing infant including extrapyramidal reactions, sedation, and metabolic disturbances, breastfeeding is contraindicated during therapy and for 5 days after the last dose. |
| Teratogenic Risk | TORECAN (thiethylperazine) is classified as FDA Pregnancy Category X. First trimester: known to cause teratogenic effects including neural tube defects, limb deformities, and cardiac anomalies. Second trimester: associated with fetal growth restriction and neurodevelopmental delays. Third trimester: risk of neonatal extrapyramidal symptoms, respiratory depression, and withdrawal symptoms. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to thiethylperazine or other phenothiazines","Comatose patients","Central nervous system depression (e.g., due to alcohol, barbiturates, or narcotics)","Concomitant use with drugs that prolong QT interval"]
| Precautions | ["May cause extrapyramidal symptoms (EPS), including dystonia, akathisia, and tardive dyskinesia","Risk of neuroleptic malignant syndrome (NMS)","Sedation and dizziness may impair ability to drive or operate machinery","QT interval prolongation and risk of torsades de pointes","Use with caution in patients with epilepsy or history of seizures","May mask signs of toxicity due to other drugs or conditions"] |
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| Fetal Monitoring | Maternal monitoring: baseline and periodic liver function tests, complete blood counts, and ECG for QT prolongation. Fetal monitoring: serial ultrasound for fetal growth and anatomy, cardiotocography in third trimester, and neonatal assessment for extrapyramidal signs and respiratory depression upon delivery. |
| Fertility Effects | TORECAN may increase serum prolactin levels, leading to galactorrhea, amenorrhea, and menstrual irregularities in females, potentially impairing fertility. In males, hyperprolactinemia can cause gynecomastia and erectile dysfunction. The impact on fertility is generally reversible upon discontinuation. |