Severe lactic acidosis after an iatrogenic propylene glycol overdose.

Propylene glycol is a diluent found in many intravenous and oral drugs, including phenytoin, diazepam, and lorazepam. Propylene glycol is eliminated from the body by oxidation through alcohol dehydrogenase to form lactic acid. Under normal conditions, the body converts lactate to pyruvate and metabolizes pyruvate through the Krebs cycle. Lactic acidosis has occurred in patients, often those with renal dysfunction, who were receiving prolonged infusions of drugs that contain propylene glycol as a diluent. We describe a 50-year-old man who experienced severe lactic acidosis after receiving an accidental overdose of lorazepam, which contains propylene glycol. The patient was acutely intoxicated, with a serum ethanol concentration of 406 mg/dl. He had choked on a large piece of meat and subsequently experienced pulseless electrical activity with ventricular fibrillation cardiac arrest. He was brought to the emergency department; within 2 hours, he was admitted to the intensive care unit for initiation of the hypothermia protocol. The patient began to experience generalized tonic-clonic seizures 12 hours later, which resolved after several boluses of lorazepam. A lorazepam infusion was started; however, it was inadvertently administered at a rate of 2 mg/minute instead of the standard rate of 2 mg/hour. Ten hours later, the administration error was recognized and the infusion stopped. The patient's peak propylene glycol level was 659 mg/dl, pH 6.9, serum bicarbonate level 5 mEq/L, and lactate level 18.6 mmol/L. Fomepizole was started the next day and was continued until hospital day 3. Continuous renal replacement therapy was started and then replaced with continuous venovenous hemofiltration (CVVH) for the remainder of the hospital stay. The patient's acidosis resolved by day 3, when his propylene glycol level had decreased to 45 mg/dl. Fomepizole was discontinued, but the patient's prognosis was poor (anoxic brain injury); thus care was withdrawn and the patient died. Although the patient's outcome was death, his lactic acidosis was treated successfully with fomepizole and CVVH. Clinicians should be aware that an iatrogenic overdose of lorazepam may result in severe propylene glycol toxicity, which may be treated with fomepizole and CVVH.

[Intoxication with propylene glycol in two horses]. / Een intoxicatie met propyleenglycol bij twee paarden.

Two horses were accidentally administered propylene glycol instead of mineral oil. After discovery of the mistake intensive medical therapy with intravenous fluids, etc. was started, and both animals recovered fully from their clinical symptoms. Veterinarians use propylene glycol as well as paraffin routinely for the treatment of their patients. Mistakes are likely to be made because both medicines and sometimes their packing have a similar appearance. Several incidents have been reported in other countries. A large amount of propylene glycol given to a horse, but also to other animals, can be dangerous and immediate adequate intervention is necessary. The major cause of the problems in case of a propylene glycol intoxication is the high concentration of D-lactate that arises. Clinically, this primarily results in a depression of the central nervous system and in metabolic acidosis. Furthermore colic, diarrhoea and respiratory problems may occur.

Screening of urine by one-dimensional and pulsed-field gradient two-dimensional 1H NMR spectroscopy: intoxication by propylene glycol in an infant patient.

1H NMR spectroscopy is a promising method for the analysis of physiological fluids in clinical medicine. In the course of screening the urine of patients by 1D- and pulsed-field gradient 2D 1H NMR spectroscopy at 500 MHz, we encountered a case with a very high excretion of propylene glycol compared to others who received similar doses of the medication. In this case, the propylene glycol was scarcely metabolized by the patient. Propylene glycol is widely used as a safety material which is transformed into pyruvate and lactate in the healthy body. In this paper, we discuss how NMR spectroscopy can be a useful method for screening a patient intoxicated with propylene glycol.

Propylene glycol: the safe diluent that continues to cause harm.

Propylene glycol (PG) is present in many pharmaceutical products, lotions, ointments, and cosmetics. Although considered to be a relatively safe substance, overdoses have been associated with serious adverse effects. Propylene glycol intoxication occurred in a child and caused central nervous system depression and a severe metabolic acidosis. Initial assessment revealed an elevated serum anion gap, a slight increase in measured serum osmolality, and a normal osmolal gap. The child's acidosis was due to increased concentrations of lactate and pyruvate. The possibility of serious PG intoxication should be considered in any patient with an unexplained serious metabolic acidosis.