Toxic Dose of Chlorprothixene
Severe chlorprothixene toxicity occurs at doses of 2 grams or more in adults, though serious toxic manifestations can occur at much lower doses in children (less than 5 mg/kg body weight), and doses as low as 1,800-2,000 mg have required intubation in overdose cases 1, 2.
Dose-Toxicity Relationship
Adults
- Severe intoxication threshold: ≥2,000 mg (2 grams) 1
- Intubation-associated doses: Median of 2,000 mg (range 1,388-3,375 mg) in overdose cases requiring intubation 2
- Fatal case reported: One unexpected death occurred 49 hours after ingestion, demonstrating delayed cardiac complications 1
- Massive overdose case: A patient survived 10 grams with cardiorespiratory arrest, ventricular fibrillation, and required hemoperfusion 3
Pediatric Population
- Much lower toxic threshold: Serious toxic manifestations observed at <5 mg/kg body weight 1
- Children are significantly more vulnerable to toxicity at proportionally lower doses
Clinical Manifestations of Toxicity
The primary toxic effects include:
- Central nervous system depression: Most common effect, with Glasgow Coma Scale <9 in 27% of overdose cases 2
- Cardiovascular complications:
- Seizures: Occurred in 4% of overdose cases 2
- Delirium: 8% of cases 2
Critical Clinical Considerations
A major pitfall is assuming early clinical stability indicates safety—one fatal case demonstrated cardiac failure occurring 49 hours after ingestion, emphasizing the need for prolonged monitoring even in apparently stable patients 1.
Dose-Outcome Correlation
A retrospective analysis of 218 chlorprothixene overdoses found a significant association between reported dose ingested and requirement for intensive care admission and endotracheal intubation (p<0.001) 2. The median dose in patients requiring intubation was 2,000 mg versus 1,200 mg in those not requiring intubation.
Co-ingestions
In 62% of overdose presentations, other medications were co-ingested (typically benzodiazepines, paracetamol, or other antipsychotics), which can complicate the clinical picture 2.
Management Implications
Based on the case where favorable outcome occurred with combined gut and gastric lavage, aggressive gastrointestinal decontamination may be valuable in chlorprothixene intoxication 1. In severe cases with cardiovascular instability, hemoperfusion has been used successfully, though it removed only 1.6% of the estimated dose—suggesting clinical improvement may relate to redistribution rather than total drug removal 3.
Monitor all patients for at least 48-72 hours post-ingestion given the documented case of delayed cardiac death at 49 hours 1.