STELAZINE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for STELAZINE (STELAZINE).
Antipsychotic agent; blocks postsynaptic dopamine D1 and D2 receptors in the brain; also exhibits anticholinergic, alpha-adrenergic, and antihistaminergic effects.
| Metabolism | Hepatic via CYP450 enzymes (primarily CYP2D6); also undergoes N-demethylation and sulfoxidation. |
| Excretion | Primarily renal (metabolites and unchanged drug; ~50% as metabolites); biliary/fecal excretion accounts for <20%. |
| Half-life | Terminal elimination half-life is approximately 24-30 hours (up to 40 hours in chronic use). Clinical context: Steady-state is reached in 5-7 days; allows once- or twice-daily dosing. |
| Protein binding | 92-97% bound to albumin and alpha-1 acid glycoprotein. |
| Volume of Distribution | Approximately 18-30 L/kg (0.5-1.5 L/kg). Clinical meaning: Extensive tissue distribution with high CNS penetration. |
| Bioavailability | Oral: ~40% (due to first-pass metabolism); IM: 100%. |
| Onset of Action | Oral: 30-60 minutes; IM: 15-30 minutes; IV: 5-10 minutes. Antipsychotic effect may take days to weeks. |
| Duration of Action | Oral: 4-6 hours for single dose (antipsychotic effect persists longer); IM/IV: 4-6 hours. Clinical note: Extrapyramidal effects may outlast therapeutic effect. |
| Molecular Weight | 480.42 |
Adults: 2-10 mg orally twice daily; maximum 40 mg/day.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment recommended; use caution in severe renal impairment. |
| Liver impairment | Child-Pugh A: no adjustment. Child-Pugh B: reduce dose by 50%. Child-Pugh C: avoid use or reduce dose by 75%. |
| Pediatric use | Children 6-12 years: 1 mg 1-2 times daily; increase gradually up to 15 mg/day. Children >12 years: adult dosing. |
| Geriatric use | Initiate at 1-2 mg twice daily; titrate slowly due to increased sensitivity and risk of orthostatic hypotension and extrapyramidal symptoms. |
| 1st trimester | Avoid if possible; may cause fetal malformations in animal studies, but human data limited. Use only if benefit outweighs risk. |
| 2nd trimester | Avoid if possible; may affect fetal development and maternal safety (e.g., extrapyramidal symptoms). |
| 3rd trimester | Avoid near term; may cause neonatal extrapyramidal symptoms, agitation, or withdrawal after delivery. |
Clinical note
Comprehensive clinical and safety monograph for STELAZINE (STELAZINE).
| Placental transfer | Trifluoperazine crosses the placenta; degree is poorly quantified but similar to other typical antipsychotics. |
| Breastfeeding | Trifluoperazine is excreted into breast milk in low amounts. Monitor infant for drowsiness, irritability, and feeding difficulties. Avoid in mothers of premature or sick infants. Consider the lowest effective dose. |
■ FDA Black Box Warning
Increased mortality in elderly patients with dementia-related psychosis.
| Serious Effects |
Hypersensitivity to trifluoperazine or any phenothiazineComatose statesCNS depression from any causeBone marrow suppressionPreexisting liver disease with impaired function
| Precautions | Tardive dyskinesia, neuroleptic malignant syndrome, QT prolongation, leukopenia/neutropenia/agranulocytosis, seizure threshold lowering, anticholinergic effects, hypotension, cholestatic jaundice, ocular changes (corneal/lenticular deposits). |
| Food/Dietary | Avoid alcohol and CNS depressants. Grapefruit juice may increase drug levels; avoid concurrent use. Limit caffeine intake. No specific dietary restrictions, but monitor weight gain due to increased appetite. |
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| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | First trimester: Limited data; possible increased risk of congenital malformations (neural tube defects, cardiovascular) based on some retrospective studies. Second/third trimesters: Risk of extrapyramidal symptoms, jaundice, and hyperreflexia in neonates with late exposure. Case reports of neonatal withdrawal and EPS. Not a known major teratogen but use only if benefits outweigh risks. |
| Fetal Monitoring | Maternal: Baseline and periodic LFTs, CBC, EKG (QTc), blood glucose, and weight. Monitor for EPS and tardive dyskinesia. Fetal: Third trimester ultrasound for growth; neonatal monitoring for EPS, jaundice, and neurobehavioral issues at birth. |
| Fertility Effects | May cause hyperprolactinemia, leading to menstrual irregularities, anovulation, and reduced fertility in females. Reversible upon discontinuation. In males, possible decreased libido and erectile dysfunction. No known effect on spermatogenesis. |
| Clinical Pearls | Extrapyramidal symptoms (EPS) are common; use benztropine prophylactically in young males. Monitor for QT prolongation, especially in elderly. Avoid in patients with history of tardive dyskinesia. Can cause orthostatic hypotension; titrate slowly. Neuroleptic malignant syndrome (NMS) rare but serious; discontinue immediately if hyperthermia, rigidity, autonomic instability occur. |
| Patient Advice | Take exactly as prescribed; do not stop abruptly. · May cause dizziness upon standing; rise slowly from sitting or lying down. · Report any involuntary muscle movements, stiffness, or tremors to your doctor. · Avoid alcohol and other central nervous system depressants. · May cause drowsiness; use caution when driving or operating machinery. · Notify your doctor if you experience rapid heartbeat, fainting, or fever with muscle rigidity. · Avoid exposure to extreme heat (can impair body temperature regulation). · Store at room temperature away from light and moisture. |