THIOTHIXENE HYDROCHLORIDE INTENSOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for THIOTHIXENE HYDROCHLORIDE INTENSOL (THIOTHIXENE HYDROCHLORIDE INTENSOL).
Thiothixene is a typical antipsychotic that blocks postsynaptic dopamine D1 and D2 receptors in the central nervous system, particularly in the mesolimbic and mesocortical pathways. It also has affinity for serotonin 5-HT2, histamine H1, and alpha-1 adrenergic receptors, contributing to its therapeutic and adverse effects.
| Metabolism | Extensively metabolized in the liver via sulfoxidation, N-demethylation, and N-oxidation. Involves CYP450 enzymes, primarily CYP1A2. |
| Excretion | Primarily renal and biliary; about 50-60% of a single dose is excreted in the urine as metabolites and unchanged drug within 48 hours, with approximately 30-40% eliminated in feces via biliary secretion. Less than 1% of the parent drug is excreted unchanged in urine. |
| Half-life | Terminal elimination half-life ranges from 26 to 36 hours in healthy adults, allowing for once-daily dosing in maintenance therapy. In chronic use, the half-life may be prolonged due to accumulation. |
| Protein binding | >95% bound primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Approximately 10-20 L/kg, indicating extensive tissue distribution and accumulation in peripheral compartments. |
| Bioavailability | Oral: >90% (well absorbed but undergoes first-pass metabolism, resulting in approximately 50-60% bioavailability); Intramuscular: 100% bioavailable. |
| Onset of Action | Oral: 2-6 hours; Intramuscular: 30-60 minutes; Onset may be delayed in some patients. |
| Duration of Action | Oral: Effects last 12-24 hours, with antipsychotic effects persisting for days after discontinuation; Intramuscular: 4-6 hours for acute effects. |
Initial: 2 mg orally three times daily. Maintenance: 15-30 mg orally daily in divided doses. Maximum: 60 mg/day.
| Dosage form | CONCENTRATE |
| Renal impairment | No specific GFR-based dose adjustments are recommended; use with caution in renal impairment due to potential accumulation. |
| Liver impairment | Child-Pugh Class A: No adjustment. Class B: Reduce dose by 25-50%. Class C: Avoid use or reduce dose by 50-75%. |
| Pediatric use | For children >12 years: Initial 2 mg three times daily; titrate to 15-30 mg/day in divided doses. Maximum 60 mg/day. Safety/efficacy in <12 years not established. |
| Geriatric use | Initial dose: 1-2 mg twice daily; titrate slowly. Lower maintenance doses (e.g., 10-20 mg/day) recommended due to increased sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for THIOTHIXENE HYDROCHLORIDE INTENSOL (THIOTHIXENE HYDROCHLORIDE INTENSOL).
| Breastfeeding | Thiothixene is excreted into human breast milk; the milk-to-plasma ratio is not well established. Limited data suggest low levels. Due to the potential for adverse effects in the nursing infant, including sedation and extrapyramidal effects, caution is advised. Alternatives should be considered, especially if higher doses are used. |
| Teratogenic Risk | Thiothixene is a typical antipsychotic of the thioxanthene class. Data on teratogenicity in humans are limited. In the first trimester, there is a potential for malformations, though a specific pattern has not been established. Second and third trimester exposure may be associated with extrapyramidal symptoms and/or withdrawal symptoms in the neonate, including agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding difficulties. The risk is considered low to moderate. |
■ FDA Black Box Warning
Elderly patients with dementia-related psychosis treated with antipsychotic drugs are at an increased risk of death. Thiothixene is not approved for the treatment of dementia-related psychosis.
| Serious Effects |
["Hypersensitivity to thiothixene or any component of the formulation","Comatose states","CNS depression from alcohol, barbiturates, or other sedatives","Severe cardiovascular disease (e.g., hypotension, heart failure)","Blood dyscrasias","Pheochromocytoma"]
| Precautions | ["Increased mortality in elderly patients with dementia-related psychosis","Tardive dyskinesia","Neuroleptic malignant syndrome (NMS)","QT prolongation and risk of arrhythmias","Seizures","Leukopenia, neutropenia, and agranulocytosis","Orthostatic hypotension","Hyperprolactinemia","Temperature dysregulation","Anticholinergic effects"] |
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| Fetal Monitoring | Monitor the mother for therapeutic response and adverse effects such as extrapyramidal symptoms, sedation, hypotension, and QTc prolongation. Fetal/neonatal monitoring should include assessment for extrapyramidal symptoms, withdrawal symptoms, and adaptation after delivery. Consider neonatal ECG if maternal QTc prolongation is present. |
| Fertility Effects | Thiothixene may increase prolactin levels, potentially leading to galactorrhea, amenorrhea, and anovulation in women, and decreased libido or gynecomastia in men. These effects may impair fertility. The impact is reversible upon discontinuation. |