Colchicine poisoning-overview and new directions

[Accidental colchicine intoxication in a cross-breed dog]

A 2-year old cross-breed dog presented due to acute vomiting and progressive lethargy following ingestion of the owner's anti-gout medication (colchicine, 0.35 mg/kg) 1-3 hours prior to presentation.The dog developed signs of all 3 stages of colchicine poisoning (gastrointestinal phase, multi-organ phase, recovery phase) and the clinical course was complicated by the presence of multi-organ dysfunction syndrome (MODS) and numerous negative prognostic factors.This case report describes the clinical and laboratory effects of colchicine poisoning and represents the first successful treatment of an accidental colchicine ingestion in a dog in Europe.

Anti-colchicine Fab fragments prevent lethal colchicine toxicity in a porcine model: a pharmacokinetic and clinical study

Background: Colchicine poisoning is commonly lethal. Colchicine-specific Fab fragments increase rat urinary colchicine clearance and have been associated with a good outcome in one patient. We aimed to develop a porcine model of colchicine toxicity to study the pharmacokinetics and efficacy of ovine Fab.

Methods: A Göttingen minipig critical care model was established and serial blood samples taken for colchicine and Fab pharmacokinetics, clinical chemistry, and haematology. Animals were euthanised when the mean arterial pressure fell below 45 mmHg without response to vasopressor, or at study completion.

Results: Initial studies indicated that oral dosing produced variable pharmacokinetics and time-to-euthanasia. By contrast, intravenous infusion of 0.25 mg/kg colchicine over 1 h produced reproducible pharmacokinetics (AUC_0–20 343 [SD = 21] µg/L/h), acute multi-organ injury, and cardiotoxicity requiring euthanasia a mean of 22.5 (SD = 3.2) h after dosing. A full-neutralising equimolar Fab dose given 6 h after the infusion (50% first hour, 50% next 6 h [to reduce renal-loss of unbound Fab]) produced a 7.35-fold increase in plasma colchicine (AUC_0–20 2,522 [SD = 14] µg/L/h), and removed all free plasma colchicine, but did not prevent toxicity (euthanasia at 29.1 [SD = 3.4] h). Earlier administration over 1 h of the full-neutralising dose, 1 or 3 h after the colchicine, produced a 12.9-fold (AUC_0–20 4,433 [SD = 607] µg/L/h) and 6.0-fold (AUC_0–20 2,047 [SD = 51] µg/L/h) increase in plasma colchicine, respectively, absence of free plasma colchicine until 20 h, and survival to study end without marked cardiotoxicity.

Conclusions: Colchicine-specific Fab given early, in equimolar dose, bound colchicine, eliciting its movement into the blood, and preventing severe toxicity. Clinical studies are now needed to determine how soon this antidote must be given to work in human poisoning.

Acute colchicine intoxication in a child: a case report

Colchicine poisoning is an uncommon, but potentially life-threatening, toxicologic emergency. The clinical features associated with overdose and the options for treatment are discussed. Colchicine poisoning typically shows 3 phases: initially, gastrointestinal symptoms predominate; in the second phase, multiorgan failure may occur, possibly leading to death. If the patient survives, the third phase of recovery follows, during which the patient often presents with hair loss. Early fatality is due to cardiovascular collapse and respiratory failure; however, pancytopenia and overwhelming septicemia can occur later. All patients suspected of having colchicine intoxication because of its unpredictable outcome should be managed according to the principles of intensive care, irrespective of the actual degree of poisoning. In those patients who survive the initial phase of poisoning, filgrastim (granulocyte colony-stimulating factor) offers an effective method of treating pancytopenia and preventing overwhelming septicemia. Daily monitoring of the patients' hematological status is strongly recommended. We are reporting a case of previously healthy girl who developed a multisystem organ failure after colchicine intoxication. The patient recovered completely and had no residual outcome.

Toxic epidermal necrolysis-like reaction secondary to colchicine overdose

Colchicine is a microtubule-inhibiting drug used to treat gout, familial Mediterranean fever and many other skin diseases. Intoxication with colchicine affects multiple organs, often fatally. Cutaneous sequelae of colchicine toxicity are rare. We describe the clinical and histological features of a toxic epidermal necrolysis-like exanthem in a patient who lethally overdosed on colchicine.

Colchicine-induced bone marrow suppression: treatment with granulocyte colony-stimulating factor

Bone marrow aplasia is a frequent complication of colchicine poisoning. This typically occurs on day 3 to 5 postexposure, and the blood cell counts remain depressed for a week or more. Unfortunately, because patients suffering from colchicine toxicity develop multiple organ complications and sepsis, the morbidity and mortality associated with bone marrow depression is high. In this article, we present three cases of colchicine toxicity in which granulocyte colony-stimulating factor (G-CSF) was used to treat bone marrow depression. In all three cases, there was a dramatic increase in the white cell count and, to a lesser extent, the platelet count. In view of the critical nature of the bone marrow depression and multi-organ toxicity induced by colchicine, we believe that consideration of the use of G-CSF to shorten the duration of neutropenia is warranted.