Bone marrow depression associated with acute colchicine toxicity in the presence of hepatic dysfunction

[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.

Colchicine poisoning: the dark side of an ancient drug

INTRODUCTION

Colchicine is used mainly for the treatment and prevention of gout and for familial Mediterranean fever (FMF). It has a narrow therapeutic index, with no clear-cut distinction between nontoxic, toxic, and lethal doses, causing substantial confusion among clinicians. Although colchicine poisoning is sometimes intentional, unintentional toxicity is common and often associated with a poor outcome.

METHODS

We performed a systematic review by searching OVID MEDLINE between 1966 and January 2010. The search strategy included "colchicine" and "poisoning" or "overdose" or "toxicity" or "intoxication."

TOXICOKINETICS

Colchicine is readily absorbed after oral administration, but undergoes extensive first-pass metabolism. It is widely distributed and binds to intracellular elements. Colchicine is primarily metabolized by the liver, undergoes significant enterohepatic re-circulation, and is also excreted by the kidneys. THERAPEUTIC AND TOXIC DOSES: The usual adult oral doses for FMF is 1.2-2.4 mg/day; in acute gout 1.2 mg/day and for gout prophylaxis 0.5-0.6 mg/day three to four times a week. High fatality rate was reported after acute ingestions exceeding 0.5 mg/kg. The lowest reported lethal doses of oral colchicine are 7-26 mg.

DRUG INTERACTIONS

CYP 3A4 and P-glycoprotein inhibitors, such as clarithromycin, erythromycin, ketoconazole, ciclosporin, and natural grapefruit juice can increase colchicine concentrations. Co-administration with statins may increase the risk of myopathy.

MECHANISMS OF TOXICITY

Colchicine's toxicity is an extension of its mechanism of action - binding to tubulin and disrupting the microtubular network. As a result, affected cells experience impaired protein assembly, decreased endocytosis and exocytosis, altered cell morphology, decreased cellular motility, arrest of mitosis, and interrupted cardiac myocyte conduction and contractility. The culmination of these mechanisms leads to multi-organ dysfunction and failure. REPRODUCTIVE TOXICOLOGY AND LACTATION: Colchicine was not shown to adversely affect reproductive potential in males or females. It crosses the placenta but there is no evidence of fetal toxicity. Colchicine is excreted into breast milk and considered compatible with lactation.

CLINICAL FEATURES

Colchicine poisoning presents in three sequential and usually overlapping phases: 1) 10-24 h after ingestion - gastrointestinal phase mimicking gastroenteritis may be absent after intravenous administration; 2) 24 h to 7 days after ingestion - multi-organ dysfunction. Death results from rapidly progressive multi-organ failure and sepsis. Delayed presentation, pre-existing renal or liver impairment are associated with poor prognosis. 3) Recovery typically occurs within a few weeks of ingestion, and is generally a complete recovery barring complications of the acute illness.

DIAGNOSIS

History of ingestion of tablets, parenteral administration, or consumption of colchicine-containing plants suggest the diagnosis. Colchicine poisoning should be suspected in patients with access to the drug and the typical toxidrome (gastroenteritis, hypotension, lactic acidosis, and prerenal azotemia).

MANAGEMENT

Timely gastrointestinal decontamination should be considered with activated charcoal, and very large, recent (<60 min) ingestions may warrant gastric lavage. Supportive treatments including administration of granulocyte colony-stimulating factor are the mainstay of treatment. Although a specific experimental treatment (Fab fragment antibodies) for colchicine poisoning has been used, it is not commercially available.

CONCLUSION

Although colchicine poisoning is relatively uncommon, it is imperative to recognize its features as it is associated with a high mortality rate when missed.

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.

Colchicine in dermatology

Colchicine is a medication most often used to treat symptoms of gout. This drug has also been shown to have beneficial effects on cutaneous conditions, including leukocytoclastic vasculitis, psoriasis, and Sweet's syndrome. Colchicine inhibits the function of polymorphonuclear leukocytes, and dermatoses with a strong presence of these cells may benefit the most from the administration of this medication. A review of the pharmacology, mechanism of action, and adverse reactions of colchicine is also presented.

Colchicine intoxication: clinical pharmacology, risk factors, features, and management

The use of colchicine for acute gouty arthritis dates to ancient times. In recent years, colchicine also has been used successfully for various other rheumatic and nonrheumatic conditions. Colchicine is a safe drug when used according to established therapeutic guidelines. However, toxicity can be considerable if ingested intentionally or if the recommended doses are exceeded. Colchicine intoxication is characterized by multi-organ involvement and by the poor prognosis associated with administration of large amounts of the drug. Therapy is basically supportive and symptomatic because of the rapid distribution and binding of colchicine to the affected tissues. Use of anticolchicine antibodies is a novel approach that has shown promise in experimental models. Important research questions pertain to the effect of liver and kidney disease on colchicine metabolism, use of colchicine levels in the diagnosis of intoxication and for prognostication, and application of immunotoxicotherapy for colchicine poisoning in humans.

Colchicine cardiotoxicity following ingestion of Gloriosa superba tubers

The clinical features of colchicine toxicity in a patient following ingestion of Gloriosa superba tubers are described. Gastroenteritis, acute renal failure, cardiotoxicity and haematological abnormalities were the main toxic manifestations. There was no hypotension and no neurological manifestations. Electrocardiographic changes were noteworthy and have not been reported previously.

Zero-order absorption and linear disposition of oral colchicine in healthy volunteers

The pharmacokinetics of colchicine has been studied in nine healthy male volunteers after oral doses of 0.5, 1, and 1.5 mg as tablets. Plasma and urine samples were collected over 48 h and analysed for colchicine by radioimmunoassay. Individual colchicine concentration profiles in plasma and urine were well described by a two-compartment open model with zero-order input. Considering the absorption variables as specific to each experiment, the lag time (0-0.35 h) and duration (0.39-2.38 h) of absorption were found to be independent of dose, while the zero-order rate constant of absorption (k0) increased linearly with dose. Disposition variables were taken as common to the three experiments, except in six subjects in whom renal excretion varied significantly across experiments in a dose-independent manner. For seven subjects the terminal half-life was 19.4 h, the oral apparent volume of distribution at steady-state (Vss/f) was 691 l, and the oral systemic clearance (CL/f) was 33.1 l.h-1. In the two other subjects, the values were unreliable, but the estimated terminal half-life was greater than 48 h, Vss/f ranged from 1690 to 3480 l, and CL/f was in the range of the other subjects in 1 subject, and it was about 15 l.h-1 in the other. In the latter subject, these estimates, together with the observation that plasma concentration reached a plateau at 2 to 5 h after ingestion, suggest enterohepatic cycling of colchicine. Overall, the disposition of colchicine was linear in the dose range 0.5-1.5 mg, with a long terminal half-life, and absorption obeyed zero-order kinetics, with k0 proportional to dose.

Granulocytopenia complicating colchicine therapy for primary biliary cirrhosis

A case is presented of a 76-yr-old woman with primary biliary cirrhosis and adult polycystic liver disease who developed bone marrow toxicity associated with chronic low-dose colchicine therapy. Two months after starting colchicine therapy (0.6 mg b.i.d. p.o.), the patient developed hematologic toxicity as evidenced by transient but profound granulocytopenia which promptly reversed 4 days after the drug was stopped. Bone marrow examination revealed moderate hypocellularity of all cell lines and striking dysplastic changes in the late myeloid and erythroid series. There was no apparent toxicity involving other organ systems. The patient fully recovered. This case is compared with previous descriptions of colchicine toxicity.

The effect of intraperitoneal colchicine on the formation of peritoneal adhesions in the rat

A double blind study was carried out to determine the effect of colchicine on the formation of intraperitoneal adhesions in the rat. Adhesions were produced by a standard method in 92 rats. The animals were than divided at random into two groups. One group (47 rats) was treated with intraperitoneal colchicine, whilst the other, the control group (45 rats) was treated with intraperitoneal normal saline in the same volume, frequency and duration. Four weeks later the animals were killed for assessment and measurement of adhesions. Two kinds of adhesions were found. 1. "Surface adhesion" - consisting of two serosal surfaces attached together; their area was significantly smaller (p less than 0.00003), and their number was lower (p less than 0.03) in the colchicine group than in the control group. 2. "Filamentous adhesions" - thin, elastic cords connecting omentum or pelvic fat bodies to other viscera; there was no significant difference in their number between the colchicine and the control group. We concluded that post-operative treatment with colchicine reduces the formation of intraperitoneal adhesions in the rat.

Colchicine overdose: report of two cases and review of the literature

Colchicine overdose is an uncommon but serious problem that may be missed or ignored unless the physician is aware of the significant potential for, and the various stages of, toxicity. We report two fatal cases in which the potential for lethal complications was not initially realized. Both patients developed multiple organ damage characteristic of severe colchicine toxicity. Awareness and appropriate initial therapy are important if death is to be prevented in colchicine overdose.

Marrow aplasia induced by colchicine. A case report

A 70 year old male developed marrow aplasia and pancytopenia after receiving 10 mg of colchicine intravenously over a period of 5 days for acute gouty arthritis. Despite a fatal outcome, evidence of recovery of hematopoiesis was observed in the bone marrow 3 days after the last dose of the drug. The pathogenetic mechanism by which colchicine induced marrow aplasia in this patient remains unclear.