American Academy of Clinical Toxicology Practice Guidelines on the Treatment of Ethylene Glycol Poisoning. Ad Hoc Committee.

Fomepizole (4-methylpyrazole, 4-MP, Antizol) is a potent inhibitor of alcohol dehydrogenase that was approved recently by the US Food and Drug Administration (FDA) for the treatment of ethylene glycol poisoning. Although ethanol is the traditional antidote for ethylene glycol poisoning, it has not been studied prospectively. Furthermore, the FDA has not approved the use of ethanol for this purpose. Case reports and a prospective case series indicate that the intravenous (i.v.) administration of fomepizole every 12 hours prevents renal damage and metabolic abnormalities associated with the conversion of ethylene glycol to toxic metabolites. Currently, there are insufficient data to define the relative role of fomepizole and ethanol in the treatment of ethylene glycol poisoning. Fomepizole has clear advantages over ethanol in terms of validated efficacy, predictable pharmacokinetics, ease of administration, and lack of adverse effects, whereas ethanol has clear advantages over fomepizole in terms of long-term clinical experience and acquisition cost. The overall comparative cost of medical treatment using each antidote requires further study.     

Massive Ethylene Glycol Ingestion Treated with Fomepizole Alone—A Viable Therapeutic Option

Fomepizole is used to treat and prevent toxicity from ethylene glycol poisoning. Treatment with fomepizole without hemodialysis in massive ethylene glycol ingestion has been rarely reported in the literature; however, published literature and practice guidelines recommend considering dialysis for ethylene glycol levels >50 mg/dL. We report a case of massive ethylene glycol ingestion resulting in the highest serum ethylene glycol concentration in a patient without ethanol co-ingestion who was treated with fomepizole and was not hemodialyzed. A 48-year-old male presented to the emergency department after reportedly ingesting >1liter of antifreeze in an attempt at self-harm. He denied concomitant ethanol consumption. His initial presenting serum ethylene glycol level was 700 mg/dL, with normal renal function, and a metabolic acidosis with a high anion gap. One hour after presentation, he was started on intravenous fomepizole. Treatment with fomepizole continued until the patient's plasma ethylene glycol concentration was 16 mg/dL. His metabolic acidosis quickly resolved, he had no adverse reactions to the treatment, and his renal function remained normal. Ultimately, he was discharged to a psychiatric unit without sequelae. Published literature and practice guidelines suggests considering hemodialysis initiation in patients with an ethylene glycol level >50 mg/dL. This recommendation is anecdotally, rather than evidence, based. With the potential risks inherent in hemodialysis, our case provides evidence that treatment with fomepizole without hemodialysis appears to be a viable alternative option in patients with even extremely high plasma ethylene glycol concentrations as long as their renal function is intact.     

Current management of ethylene glycol poisoning.

Ethylene glycol, a common antifreeze, coolant and industrial solvent, is responsible for many instances of accidental and intentional poisoning annually. Following ingestion, ethylene glycol is first hepatically metabolised to glycoaldehyde by alcohol dehydrogenase. Glycoaldehyde is then oxidised to glycolic acid, glyoxylic acid and finally oxalic acid. While ethylene glycol itself causes intoxication, the accumulation of toxic metabolites is responsible for the potentially fatal acidosis and renal failure, which characterises ethylene glycol poisoning. Treatment of ethylene glycol poisoning consists of emergent stabilisation, correction of metabolic acidosis, inhibition of further metabolism and enhancing elimination of both unmetabolised parent compound and its metabolites. The prevention of ethylene glycol metabolism is accomplished by the use of antidotes that inhibit alcohol dehydrogenase. Historically, this has been done with intoxicating doses of ethanol. At a sufficiently high concentration, ethanol saturates alcohol dehydrogenase, preventing it from acting on ethylene glycol, thus allowing the latter to be excreted unchanged by the kidneys. However, ethanol therapy is complicated by its own inherent toxicity, and the need to carefully monitor serum ethanol concentrations and adjust the rate of administration. A recent alternative to ethanol therapy is fomepizole, or 4-methylpyrazole. Like ethanol, fomepizole inhibits alcohol dehydrogenase; however it does so without producing serious adverse effects. Unlike ethanol, fomepizole is metabolised in a predictable manner, allowing for the use of a standard, validated administration regimen. Fomepizole therapy eliminates the need for the haemodialysis that is required in selected patients who are non-acidotic and have adequate renal function.     

Ethylene glycol ingestion treated only with fomepizole

Introduction

Ethylene glycol is a widely used chemical that is capable of causing significant injury if ingested. Treatment for ethylene glycol poisoning typically includes basic supportive care, alcohol dehydrogenase inhibition, and hemodialysis. Recent data have suggested that hemodialysis may not be necessary for cases of ethylene glycol poisoning that can be treated with fomepizole as blocking therapy before acidosis or renal dysfunction develops.

Case Report

A 33-year-old man presented to the emergency department 1 hour after drinking approximately 1/2 gallon of ethylene glycol antifreeze and an unknown quantity of beer. On arrival he was mildly inebriated but otherwise displayed no other features of ethylene glycol poisoning. Fomepizole therapy was initiated and initial laboratory studies later revealed an osmol gap of 157 mOsm and an ethylene glycol concentration of 706 mg/dL. Nephrology and toxicology services were consulted. Over the next 3 days, fomepizole therapy was continued while the patient’s acid-base status and renal function were closely monitored. No evidence of acid-base abnormalities or renal impairment was ever observed and the patient was discharged to psychiatric care on the fourth hospital day.

Discussion

This report describes the case of a patient who presented soon after a massive ingestion of ethylene glycol with very high serum concentrations. He was successfully treated using fomepizole and basic supportive care. Our patient developed neither renal insufficiency nor metabolic acidosis. His concomitant ethanol consumption, early presentation, and treatment likely contributed to his favorable outcome. This case report underscores the effectiveness of supportive care and fomepizole in the treatment of ethylene glycol poisoning.     

Treatment of severe pediatric ethylene glycol intoxication without hemodialysis

BACKGROUND: There is limited experience treating severe ethylene glycol poisoning in children without hemodialysis. The objective of this study was to describe the clinical course and outcome of severe pediatric ethylene glycol poisoning treated without hemodialysis. METHODS: Patient records were identified retrospectively by hospital discharge diagnosis (ICD-9 code) of ethylene glycol poisoning from 1999 through 2002 at a pediatric medial center. Patients with initial serum ethylene glycol concentrations less than 50 mg/dL or those who received hemodialysis were excluded. RESULTS: Six patients with an age range of 22 months to 14 years were admitted for treatment of ethylene glycol poisoning over a four-year period. Initial serum ethylene glycol concentrations ranged from 62 to 304 mg/dL (mean 174.0 mg/dL). The lowest-measured individual serum bicarbonates ranged from 4 to 17 mEq/L. All patients were initially admitted to intensive care. One patient received ethanol only, two patients received fomepizole only, and three patients received a loading dose of ethanol and then were converted to fomepizole therapy. None of the patients received hemodialysis. Treatment was continued until the serum ethylene glycol was less than 10 mg/dL. Metabolic acidosis resolved with intravenous fluid and supplemental bicarbonate within 24h. All patients had a normal creatinine upon presentation and at discharge. The mean length of stay in intensive care was 21h and on the ward was 33.7h. One episode of hypoglycemia occurred in a 22-month-old. All patients recovered without evidence of renal insufficiency or other major complications at discharge. CONCLUSION: Six pediatric patients with severe ethylene glycol intoxication and normal renal function were successfully treated without hemodialysis.     

Nystagmus secondary to fomepizole administration in a pediatric patient

BACKGROUND: Fomepizole is an alcohol dehydrogenase inhibitor used to treat ethylene glycol poisoning in adults, with only one report describing the use of fomepizole in the pediatric population. We report a case of nystagmus associated with fomepizole treatment of a 6-year-old female who ingested ethylene glycol 15 hours prior to admission. CASE REPORT: A previously healthy 6-year-old presented to the emergency department mottled, comatose, and with Kussmaul respirations. Initial arterial blood gases: pH 7.11, PO2 200, HCO3 2, base excess -29, and within 20 minutes her pH dropped to 7.03. The patient was responsive to pain only. Initially, crystalluria without fluorescence was observed in the emergency department; 2 hours after admission, the urine fluoresced under Wood's light. Laboratory data were significant for increased anion and osmolar gaps. She was fluid-resuscitated, NaHCO3, thiamine, and pyridoxine were administered, and she was admitted to the pediatric intensive care unit. Within 4 hours of admission, a loading dose of fomepizole (15 mg/kg) was infused due to the severity of the patient's clinical status. Hemodialysis was initiated but discontinued temporarily due to catheter thrombus formation. The initial (3-hour postadmission) ethylene glycol concentration was 13 mg/dL. She developed coarse vertical nystagmus within 2 hours of fomepizole infusion. The ethylene glycol concentration was 5 mg/dL 3 hours after hemodialysis which then was discontinued. No further fomepizole was administered and the child recovered uneventfully. CONCLUSION: There was no evidence of the more frequently cited adverse events, such as headache, nausea, and dizziness. Fomepizole has been incompletely evaluated in the pediatric population, and the nature and occurrence of adverse events have not been described adequately. The use of fomepizole appeared safe in this patient although she developed transient nystagmus.     

急性乙二醇中毒3例报告及文献回顾

乙二醇为防冻剂的主要成分。乙二醇主要在肝脏内先后代谢为羟乙醛、乙醇醛、乙醇酸及草酸。这些代谢特可导致代谢性酸中毒。典型临床表现通常为3个阶段：第1阶段在摄入后12h内，乙二醇致中枢神经系统抑制；第2阶段在摄入12～24h后，出现代谢性酸中毒和心肺疾病；第3阶段在摄入后24～72h。出现肾小管坏死和肾衰竭。乙二醇致死量为1．4-1．6ml／kg[成人（70kg）约为100m1]。一旦怀疑乙二醇中毒，应尽快测定乙二醇和乙醇酸血浓度明确诊断。中毒治疗原则包括早期及时洗胃，给予乙醇或甲吡唑解毒剂，血液透析，碳酸氢钠vitB6等。大多数乙二醇中毒患者经早期诊断治疗后可恢复正常。本文报告3例急性乙醇中毒，3例患者均为男性（48岁），每人服用防冻液约为150ml。2倒出现头痛有，1例出现上腹不适、兴奋、躁动。3倒患者在摄入乙醇后12～18h出现代谢性酸中毒，24h出现血尿。经洗胃和血液透析，给予法莫替丁40mg，10％葡萄糖酸钙20ml。4％碳酸氢钠静脉注射，38％白酒200ml口服。2倒治愈，1例于摄入乙二醇后29h死亡。     

Ethylene glycol intoxication: case report and pharmacokinetic perspectives

A 42-year-old man was brought to the emergency department with ethylene glycol intoxication. He was hemodynamically stable and had normal renal function. His serum ethylene glycol concentration was 284 mg/dl approximately 1 hour after ethylene glycol consumption. The patient was treated with fomepizole and forced diuresis. Elimination of ethylene glycol in this patient followed first-order pharmacokinetics. Elimination pharmacokinetics in this patient were compared with that in a patient who received fomepizole and hemodialysis. Fomepizole monotherapy can be given in patients without renal failure or metabolic acidosis even with serum ethylene glycol concentrations greater than 50 mg/dl. However, cost estimates based on this case suggest that if the patient is treated adequately with a single hemodialysis session and 24-hour hospitalization, then fomepizole monotherapy may be more expensive than the combination regimen of fomepizole and hemodialysis.     

Expert opinion: fomepizole may ameliorate the need for hemodialysis in methanol poisoning

Fomepizole is now the antidote of choice in methanol poisoning. The use of fomepizole may also change the indications for hemodialysis in these patients. We have addressed this change in a review of articles on methanol poisonings. Review of the literature (through PubMed) combined with our own experiences from two recent methanol outbreaks in Estonia and Norway. The efficiency of dialysis during fomepizole treatment was reported in only a few reports. One recent study challenged the old indications, suggesting a new approach with delayed or even no hemodialysis. Methanol-poisoned patients on fomepizole treatment may be separated into two categories: 1) The critically ill patient, with severe metabolic acidosis (base deficit >15 mM) and/or visual disturbances should be given buffer, fomepizole and immediate hemodialysis: dialysis removes the toxic anion formate, and assists in correcting the metabolic acidosis, thereby also reducing formate toxicity. The removal of methanol per se is not important in this setting because fomepizole prevents further production of formic acid. 2) The stable patient, with less metabolic acidosis and no visual disturbances, should be given buffer and fomepizole. This treatment allows for the possibility to delay, or even drop, dialysis in this setting, because patients will not develop more clinical features from methanol poisoning when fomepizole and bicarbonate is given in adequate doses. Indications and triage for hemodialysis in methanol poisonings should be modified. Delayed hemodialysis or even no hemodialysis may be an option in selected cases.     

Treatment of methanol and isopropanol poisoning with intravenous fomepizole

CASE REPORT: We report a case of mixed methanol and isopropanol poisoning in a patient who refused dialysis but agreed to treatment with intravenous fomepizole. The patient was asymptomatic on arrival, with initial blood methanol and isopropanol concentrations of 146 mg/dL and 39 mg/dL, respectively. Blood ethanol was undetectable. The patient was treated with fomepizole twice daily intravenously until blood methanol was undetectable. No side effects of therapy, other than transient eosinophilia, were observed. The evolution was uneventful and no metabolites of either alcohol were detected at any time during the hospitalization. The decay of plasma methanol and isopropanol under fomepizole treatment were well described by first-order kinetics. The plasma elimination half-lives of methanol and isopropanol were 47.6 hours and 27.7 hours, respectively. Fomepizole appears to have been effective in blocking the toxic metabolism of both methanol and isopropanol and was associated with a favorable outcome.     

Considerations for the treatment of ethylene glycol poisoning based on analysis of two cases

The clinical picture as well as the principles of treatment in ethylene glycol poisoning differ with the time after ingestion. These time-related differences are illustrated by two case reports. During the first hours of ethylene glycol poisoning, the patient suffers from drunkenness, vomiting and somnolence due to the intoxicant effect of ethylene glycol on the central nervous system. In the following hours a poisoning with glycolate and oxalate develops, with increasing acidosis, renal and brain damage. A patient admitted within a few hours of an overdose, with no or only slight metabolic acidosis, may be successfully treated with ethanol. If the serum concentration of ethylene glycol is very high, hemodialysis may be deferred until the necessary staff and equipment are available. If the patient is admitted with severe metabolic acidosis, hemodialysis must be started immediately. The need for ethanol administration during hemodialysis merits reevaluation.     

Triethylene glycol poisoning treated with intravenous ethanol infusion

INTRODUCTION: Poisoning with triethylene glycol has been rarely reported in humans. Triethylene glycol is thought to be metabolized by alcohol dehydrogenase to acidic products resulting in the production of a metabolic acidemia. Triethylene glycol metabolism has previously been shown to be inhibited by fomepizole (4-methyl pyrazole) administration. We report a case of triethylene glycol ingestion, presenting with a metabolic acidemia, treated with intravenous ethanol administration. CASE REPORT: A 23-year-old female presented to the emergency department approximately 1-1.5 hours following ingestion of a gulp of triethylene glycol (99%) brake fluid with coma (GCS-3) and metabolic acidemia (pH 7.03, PCO2 44 mm Hg, Bicarbonate 11 mmol/L, anion gap 30 mmol/L, serum creatinine 90 mumol/L). She was intubated and given 100 mmol of intravenous sodium bicarbonate. An ethanol loading dose was administered followed by an infusion to maintain serum ethanol at 100 mg/dL. Acidemia gradually resolved over the next 8 hours and she was extubated 12 hours later. The ethanol infusion was continued for a total of 22 hours. There was no recurrence of acidemia. Serum ethanol, ethylene glycol, and methanol levels were nondetectable on presentation, as was serum salicylate. Urine drug of abuse screen and thin-layer chromatography revealed no other coingested substances. The patient was discharged to a psychiatric ward 36 hours postingestion. CONCLUSION: Pure triethylene glycol poisoning results in coma and metabolic acidemia and may be treated with alcohol dehydrogenase inhibitors such as ethanol.     

Survival and complete recovery after severe acute ethylen glycol poisoning — a case report

Early signs of acute ethylene glycol (EG) poisoning are similar to ethanol intoxication. However, such signs of EG poisoning are followed by severe metabolic acidosis, increased anion gap, neurological and renal dysfunction, and, without adequate therapy, up to 40% mortality. Early recognition and treatment with intravenous ethanol or fomepizole and bicarbonate, renal replacement therapy, and supportive measures are the key elements of survival.     

Incorporation of therapeutic interventions in physiologically based pharmacokinetic modeling of human clinical case reports of accidental or intentional overdosing with ethylene glycol.

Although occupational uses of the high production volume (HPV) chemical ethylene glycol (EG) have not been associated with adverse effects, there are case reports where humans have either intentionally or accidentally ingested large quantities of EG, primarily from antifreeze. The acute toxicity of EG can proceed through three stages, each associated with a different metabolite: central nervous system depression (ethylene glycol), cardiopulmonary effects associated with metabolic acidosis (glycolic acid), and ultimately renal toxicity (oxalic acid), depending on the total amounts consumed and the effectiveness of therapeutic interventions. A physiologically based pharmacokinetic (PBPK) model developed in a companion paper (Corley et al., 2005). Development of a physiologically based pharmacokinetic model for ethylene glycol and its metabolite, glycolic acid, in rats and humans. Toxicol. Sci., in press 2005) was refined in this study to include clinically relevant treatment regimens for EG poisoning such as hemodialysis or metabolic inhibition with either ethanol or fomepizole. Such modifications enabled the model to describe data from several human case reports, confirming the ability of the previous model to describe the pharmacokinetics of EG and its metabolite, glycolic acid, in humans across a broad range of doses and multiple exposure routes. By integrating the case report data sets with controlled studies in this PBPK model, it was demonstrated that fomepizole, if administered early enough in a clinical situation, can be more effective than ethanol or hemodialysis in preventing the metabolism of EG to more toxic metabolites. Hemodialysis remains an important option, however, if treatment is instituted after a significant amount of EG is metabolized or if renal toxicity has occurred.     

Plasma and tissue determination of 4-methylpyrazole for pharmacokinetic analysis in acute adult and pediatric methanol/ethylene glycol poisoning

Methanol and ethylene glycol poisoning may result in severe intoxication. The inhibition of alcohol dehydrogenase by ethanol or 4-methylpyrazole (4-MP, fomepizole) is fundamental to their treatment. 4-MP presents several advantages over ethanol therapy and has been recently approved as a specific antidote for both intoxications. The authors have developed a simple gas chromatographic method to determine blood and tissue 4-MP concentrations. This method has been validated for its reproducibility (between-day CV < 6.3%), sensitivity (LOD 0.2 microg/mL), and linearity. It has been used in 4 adult patients intoxicated by methanol and 1 child accidentally intoxicated by ethylene glycol. 4-MP was used for each patient, and its blood levels were monitored every 4 hours over 2-3 days for pharmacokinetics purposes. In the population studied, after repeated administration of 10 mg/kg fomepizole, plasma 4-MP concentrations ranged from 1.4 to 21.6 microg/mL, always above the active level of 0.8 microg/mL. The mean peak concentration observed in the 4 adult patients was 18.5 +/- 2.6 microg/mL and in the child was 18.9 +/- 2.2 microg/mL. Even though 4-MP is characterized by a dose-dependent kinetic profile, under our conditions of dosage and blood sampling, its elimination better fitted a first-order kinetic model. At steady state and without any concomitant therapies, the mean apparent elimination half-life was 14.5 +/- 3 hours. Elimination seemed faster in the child. A trend toward a progessive enhancement of the 4-MP elimination rate is suggested in the pediatric case, with the duration of the treatment resulting in a t(1/2) below 5 hours after 48 hours. One patient died, and samples of blood and hepatic tissue were removed simultaneously during autopsy for 4-MP analysis. Interestingly, when the plasma concentration was subtherapeutic (<1 microg/mL) the tissue concentration observed was still significant with 12 microg/g, supporting an intermittent scheme of administration.     

Fomepizole (4-methylpyrazole) in fatal methanol poisoning with early CT scan cerebral lesions

BACKGROUND: Methanol poisoning, potentially fatal, is generally treated with the combination of ethanol as antidote, and hemodialysis. Fomepizole, a competitive inhibitor of alcohol dehydrogenase, has more recently been used, and is capable of blocking the toxic metabolism of methanol. To our knowledge, its use has never been reported as an antidote in severe methanol poisoning requiring hemodialysis. CASE REPORT: We report a case of fatal methanol poisoning (1.9 g/L on admission) suspected due to the combined presence of coma and severe metabolic acidosis with normokalaemia. CONCLUSION: The fomepizole treatment protocol (10 mg/kg by i.v. infusion over 1 hour before dialysis, repeated 12 hours later in combination with 1.5 mg/kg/h during dialysis) was simple to use and appeared effective in eliminating methanol in combination with hemodialysis. The case is also unusual in terms of severity and the early onset of cerebral lesions demonstrated by computed tomography (CT) scan.     

Treatment of a 1,4-butanediol poisoning with fomepizole

BACKGROUND: Toxicity of 1,4-butanediol, an industrial solvent and a substance of abuse, is still misunderstood and not well documented. To date, only supportive treatments are used in this poisoning. CASE REPORT: The case of a 43-year-old man who ingested 30 mL of a homemade 1,4-butanediol solution and who developed general seizures and coma has been reported here. An intravenous loading dose of fomepizole 10 mg/kg was started on admission and followed by two other doses of 10 mg/kg every 12 hour. He awoke shortly after fomepizole administration. Initial plasma 1,4-butanediol and gamma-hydroxybutyric acid concentrations, measured by gas chromatography-mass spectrometry, were 24 and 222 mg/L, respectively. Subsequent 1,4-butanediol and gamma-hydroxybutyric acid determination suggest that there was some further formate of gamma-hydroxbutyric acid after fomepizole was administered. CONCLUSION: Fomepizole administration appeared safe in this 1,4-butanediol-intoxicated patient. It is unknown whether fomepizole influenced his clinical course, but the rapid awakening observed suggests that it may have been usefuL Further experience is needed, however, to define the efficacy of this antidotal therapy in 1,4-butanediol intoxication.     

Was it necessary to add Bitrex (denatonium benzoate) to automotive products?

Oregon was the first state to mandate the addition of a bitter aversive agent to consumer automotive products containing > or = 10% ethylene glycol (EG) or > or = 4% methanol (MeOH). The 1995 Toxic Household Products statute required the addition of denatonium benzoate at a concentration of 30-50 ppm with the intent to reduce the frequency of serious pediatric exposures to these products. Retrospective review included Oregon Poison Center (OPC) records of all reported pediatric (< 6 y) exposures to automotive antifreeze (EG) and windshield washer fluid (MeOH) from 1987 through 2003, OPC charts of children treated with ethanol, fomepizole, or hemodialysis for EG or MeOH poisoning from 1987 through 2002, and coroner reports of poisoning deaths for 1994-1997 to identify EG or MeOH deaths not reported to the OPC. OPC recorded 332 EG and 117 MeOH exposures among preschool children from 1987-2003 with no change in annual frequency after 1995. No child died or suffered "major" effects before or after 1995. Ten children received ethanol infusions until laboratory results were available; 9 had no detectable concentration of the suspected agent, and 1 had a sub-toxic concentration. Two children received fomepizole but had no detectable EG. No child underwent hemodialysis. Coroner reports detected no missed pediatric deaths from toxic alcohols in 1994-1997. The mandatory addition of denatonium benzoate was unnecessary as unintentional ethylene glycol or methanol exposures in pre-school age children did not cause measurable toxicity.     

Clearance of ethylene glycol by kidneys and hemodialysis

A patient with acute ethylene glycol poisoning was treated with ethanol administration and hemodialysis, and his renal function remained consistently normal. Serial measurements of serum and urine levels of urea, creatinine, ethylene glycol, and ethanol were performed to compare the relative contributions of the hemodialyzer and the patient's kidneys in clearing ethylene glycol from the blood. Simultaneous measurements of the serum-osmolal gap (corrected for ethanol) and anion gap were correlated with these data. Mean renal clearance of ethylene glycol was 27.5 +/- 4.1 ml/min, with a fractional ethylene glycol excretion of 19.8 +/- 1.5%. This was lower than the mean urea clearance of 89.4 +/- 11.0 ml/min and fractional urea excretion of 66.0 +/- 7.8%. Hemodialyzer clearance of ethylene glycol was 156 ml/min. There was a nearly exact correlation between the serum ethylene glycol level and the corrected osmolal gap (r = 0.998, p less than 0.01). The calculated renal elimination half-life of ethylene glycol was 18 hr. We conclude that with a moderate diuresis, the normal human kidney contributes significantly to the removal of ethylene glycol from the blood. Corrected serum osmolal gap provides a nearly exact approximation of the serum ethylene glycol level and is a useful therapeutic guide.     

Fomepizole (orphan medical)

Orphan Medical has developed fomepizole as a potential treatment for both ethylene glycol and methanol poisoning. The drug was launched as Antizol in January 1998 for the treatment of ethylene glycol poisoning [273949] after US marketing approval was grantedin December 1997 [271563]. It has also received US approval for methanol poisoning [393217] and UK approval for ethylene glycol poisoning [329495]. In 1999, Orphan Medical's partner, Cambridge Laboratories, intended to pursue European approval under the mutual recognition procedure [329495]. However, by September 2000, Cambridge Laboratories had discontinued their involvement with fomepizole and IDIS World Medicines had licensed the rights to distribute the drug in the UK [412142]. In February 2000, the Canadian Therapeutic Products Programme (TPP) granted fomepizole Priority Review, provided that an NDA was submitted by March 14, 2000 [354665]. In August 2000, the TPP accepted this NDA and set a target date for approval in the fourth quarter of 2000 [379474]. The TPP granted fomepizole a Notice of Compliance permitting the sale of fomepizole in Canada in December 2000. The company's marketing partner in Canada, Paladin Labs had launched fomepizole by January 2001 [396953]. In June 2000, Tucker Anthony Cleary Gull stated that the Orphan Drug status which Orphan Medical had obtained for fomepizole would provide marketing exclusivity through December 2004. The analysts also stated that fomepizole had accounted for 40% of Orphan Medical's revenue in financial year 1999, although +/- 30% of sales were estimated to be due to stockpiling [409606].