Intravenous infusion of diazoxide in the treatment of chlorpropamide-induced hypoglycemia

Are one or two dangerous? Sulfonylurea exposure in toddlers

Sulfonylurea-based oral hypoglycemics are in widespread use in the adult population, increasing the potential for unintentional exposure in children. This article examines the risk of toxicity in children under 6 years of age who ingest one to two tablets of a sulfonylurea. We review the literature on sulfonylurea toxicity, including cases reported to the American Association of Poison Control Centers (AAPCC). The ingestion of one to two sulfonylurea tablets by a small child can lead to profound hypoglycemia with severe sequelae if untreated. As a result, all potential sulfonylurea ingestions by young children should be evaluated by a physician. A capillary glucose level must be rapidly determined at presentation and should then be repeated at regular intervals for up to 8 hours. A longer observation period is recommended for the extended release preparation of glipizide. Asymptomatic children who do not develop hypoglycemia within the recommended observation period may be safely discharged home. All children who exhibit clear symptoms of hypoglycemia or glucose levels < 60 mg/dL should be admitted for supplemental glucose (oral or intravenous), with careful observation of clinical condition and monitoring of serum glucose levels. In cases refractory to intravenous glucose, therapy with octreotide or diazoxide may be beneficial.

Management of antidiabetic medications in overdose

The drugs used to treat diabetes mellitus are diverse and involve several classes. However, these drugs can be roughly separated into hypoglycaemic agents, such as insulin and the sulphonylureas, and antihyperglycaemic agents, such as the biguanides, the alpha-glucosidase inhibitors and troglitazone. Reports of insulin overdose are rare. The major effects of insulin overdose are secondary to the insult to the CNS produced by hypoglycaemia. The mainstay of insulin overdose management is glucose replacement therapy. Sulphonylureas are the most commonly used oral antihyperglycaemic agents in the management of type 2 (non-insulin-dependent; NIDDM) diabetes mellitus. Sulphonylureas primarily cause serum glucose reduction by stimulating the release of preformed insulin from the pancreatic islets. The mainstay of sulphonylurea overdose management is glucose replacement therapy, and in severe cases, reduction of insulin release. In the large majority of patients intravenous glucose supplementation will be sufficient to maintain euglycaemia. Repaglinide, a meglitinide analogue, is a new nonsulphonylurea oral hypoglycaemic agent. In overdose, this drug may produce prolonged hypoglycaemia similar to the sulphonylureas. The primary problem with biguanide overdose is the potential for lactic acidosis. The management of biguanide overdose is largely supportive and directed at correcting the metabolic acidosis along with associated complications. The alpha-glucosidase inhibitors, acarbose, voglibose and miglitol competitively and reversibly inhibit the alpha-glucosidase enzymes (glucoamylase, sucrase, maltase and isomaltase) in the brush border in the small intestine, which delays the hydrolysis of complex carbohydrates. They appear unlikely to produce hypoglycaemia in overdose, but abdominal discomfort and diarrhoea may occur. Troglitazone is the first thiazolidinedione antidiabetic drug available. There are no data on overdose, probably because of its very recent introduction. Overdoses with antidiabetic drugs produce major morbidity, with many cases requiring intensive care medicine and prolonged hospital stays. However, fatalities are rare when treatment is initiated early. The management of the hypoglycaemic drugs (insulin and sulphonylureas) is based primarily on restoring and maintaining euglycaemia via intravenous dextrose supplementation. In the case of the sulphonylureas, reduction of insulin secretion via pharmacological intervention may also be necessary. With biguanides the main risk appears to be cardiovascular collapse secondary to profound acidosis. The management focus is on restoring acid-base balance with hyperventilation and the use of insulin to shift the utilisation of glucose from the nonoxidative pathway to the oxidative pathway. Use of haemodialysis has shown equivocal results but may be valuable in metformin overdose.

Hemiparesis and altered mental status in a child after glyburide ingestion

A normally healthy 6-year-old woke in an agitated state, limp, and moving only her left extremities. Upon arrival at the emergency department, a blood glucose measurement was 34 mg/dL. The child was lethargic, not responding to questions appropriately, and not moving her right extremities. The right arm was flexed, and the right leg was flexed and abducted. Pupils were equal and reactive, and eyes were deviated to the left. Six loose tablets of the grandmother's glyburide were found at home in the child's outdoor playhouse. Administration of glucose produced no change in the child's clinical condition. Intravenous glucose was begun at 4 mg glucose/kg/min, and the blood glucose level did not fall below 74 mg/dL after that. Over the next 48 h, the hemiparesis and mental status changes resolved without sequelae. The events of the case suggest a hypoglycemia-induced seizure with subsequent Todd's paralysis. Early direct medical evaluation in suspected glyburide ingestions in children is suggested.

Prospective multicenter study of sulfonylurea ingestion in children

OBJECTIVE

Sixty-eight percent of pediatric sulfonylurea ingestions reported to poison centers do not result in laboratory or behavioral effects. Consequently, if all exposed children are admitted overnight or for 24 hours for these exposures, it will result in 600 to 700 hospital admissions per year of children who will remain free of symptoms. We prospectively studied exposures reported to 10 regional poison centers to determine if it were possible to differentiate those patients who would have symptoms from those who would remain symptom free.

METHODS

We analyzed all sulfonylurea exposures in children < or = 12 years old reported to the participating poison centers. Hypoglycemia was defined as blood glucose (BG) concentration < 60 mg/dl.

RESULTS

Hypoglycemia developed in 56 (30%) of 185 exposed patients. Fifty-four of the 56 (96%) hypoglycemic patients had development of hypoglycemia within 8 hours of ingestion. Eighty-seven of the patients were initially managed with oral supplementation only; in 13 cases, treatment advanced to intravenous administration of glucose or glucagon with the onset of hypoglycemia. There was no statistical difference in medical outcome between patients monitored during oral supplementation versus during intravenous infusion of dextrose. Ingestions analyzed by time of day did not predict risk of hypoglycemia. Sufficient data were available for 103 (58%) of the 177 patients who ingested glyburide or glipizide to calculate a toxic dose/weight ratio. Of these 103 patients, 31 of 36 patients who ingested < or = 0.3 mg/kg remained symptom free, whereas 31 of 67 who ingested more than 0.3 mg/kg had BG concentrations < 60 mg/dl (p < 0.005, 95% confidence interval 0.05 to 0.58; sensitivity 86%, specificity 46%).

CONCLUSION

A lack of onset of hypoglycemia (BG > 60 mg/dl) in the first 8 hours after ingestion is predictive of a benign outcome in accidental pediatric sulfonylurea ingestion. Clinical observation of children for onset of hypoglycemia during oral feeding alone appears safe. Some children with symptoms of hypoglycemia need to receive intravenous dextrose therapy. Time of day of ingestion is not predictive of risk of hypoglycemia. Finally, at this time it appears inappropriate to use a milligram per kilogram body weight dose as a guide for management decisions.

Treatment of chlorpropamide overdose with diazoxide

A patient who took a chlorpropamide overdose was treated for several hours with concentrated glucose solutions, with little success in maintaining adequate serum glucose concentrations. Intravenous diazoxide administration was begun with the hope of decreasing pancreatic insulin release. After diazoxide was begun, glucose requirements decreased dramatically, and serum glucose was supranormal for most of the period of diazoxide administration. The case was complicated by the fact that the patient had taken three agents that can cause hypoglycemia--chlorpropamide, alcohol, and aspirin. Drug interactions potentiating the hypoglycemic effect of the chlorpropamide were also possible. Glucose infusion is the mainstay of therapy for a sulfonylurea overdose. However, glucose acts as a further stimulus of insulin release from a sulfonylurea-primed pancreas. Administration of concentrated glucose solutions is technically difficult because of damage to veins. Metabolic consequences of high rates of glucose infusion to hyperinsulinemic patients include hypokalemia and hypophosphatemia. Diazoxide appeared to decrease the glucose requirement in this patient, as it did in three other reported cases. Diazoxide is approved for certain hypoglycemic, hyperinsulinemic conditions. Sulfonylurea overdose represents a hypoglycemic, hyperinsulinemic condition; diazoxide appears to be an effective treatment.