SAQ 406 – Toxicology – colchicine overdose
Model Answer
Toxicology – colchicine overdose.
a. Toxic dose
- Systemic toxicity is likely at 0.5 mg/kg or greater.
b. Mechanism
- Colchicine binds tubulin, prevents microtubule formation, and inhibits mitosis, especially affecting tissues with high cell turnover.
c. Early management
- Give activated charcoal 50 g orally if airway and cooperation allow.
- Begin crystalloid resuscitation as needed and anticipate severe gastrointestinal fluid losses.
- Anticipate airway failure and need for mechanical ventilation.
- Prepare for haemodynamic instability with arterial/central access and inotropes if required.
- Correct acid-base, electrolyte, and glucose abnormalities.
- Refer early to ICU and discuss with a toxicologist.
- Manage deliberate self-harm risk, including mental health legislation if needed.
d. Toxicity over time
| Time | Expected toxicity |
|---|---|
| 2-24 hours | Nausea, vomiting, diarrhoea, abdominal pain, severe fluid loss, haemodynamic instability, and peripheral leukocytosis. |
| 2-7 days | Pancytopenia from marrow suppression, rhabdomyolysis, metabolic acidosis, respiratory failure, ARDS, dysrhythmias, and sudden cardiac death. |
| >7 days | Leukocytosis, alopecia, and recovery if the patient survives the systemic phase. |
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