Diazoxide for Neonatal Hyperinsulinemic Hypoglycemia and Pulmonary Hypertension

Mind the Decimal Point: A Case of Diazoxide Overdose-Induced Ileus

Diazoxide is the only medication approved by the United States Food and Drug Administration for the treatment of hyperinsulinism-induced hypoglycemia. Overdose is infrequently reported. This case describes a preterm four-week-old male who was prescribed diazoxide and chlorothiazide for perinatal stress-induced hyperinsulinism. The patient presented to the emergency department with feeding intolerance and abdominal distension following an accidental 10-fold diazoxide overdose. On presentation, vital signs were remarkable for tachycardia and intermittent tachypnea. Physical exam revealed a grossly distended abdomen. Laboratory abnormalities included a glucose of 216 mg/dL, sodium of 132 mmol/L, and chloride of 98 mmol/L. Abdominal X-ray interpretation found moderate gaseous distension suggestive of generalized ileus. The patient was admitted to the neonatal intensive care unit (NICU), and a nasogastric tube was placed. He received intravenous dextrose fluids, and enteral feeds were resumed as serial X-rays showed interval improvement. The patient remained in the NICU for several days to monitor bowel movements and resolution of ileus and he was discharged after improvement. While diazoxide overdose is rarely reported, and ileus due to such is documented even less frequently, 10-fold medication dose errors are common among infants. The source of the 10-fold mistake is often decimal points, leading zeros, or trailing zeros. Utilizing the smallest possible syringe for the prescribed dose may reduce the incidence of medication errors.

Neonatal Hypoglycemia

Neonatal hypoglycemia (NH) is broadly defined as a low plasma glucose concentration that elicits hypoglycemia-induced impaired brain function. To date, no universally accepted threshold (reference range) for plasma glucose levels in newborns has been published, as data consistently indicate that neurologic responses to hypoglycemia differ at various plasma glucose concentrations. Infants at risk for NH include infants of diabetic mothers, small or large for gestational age, and premature infants. Common manifestations include jitteriness, poor feeding, irritability, and encephalopathy. Neurodevelopmental morbidities associated with NH include cognitive and motor delays, cerebral palsy, vision and hearing impairment, and poor school performance. This article offers a timely discussion of the state of the science of NH and recommendations for neonatal providers focused on early identification and disease prevention.

Low-dose diazoxide is safe and effective in infants with transient hyperinsulinism

OBJECTIVE

Transient hyperinsulinism (THI) is the most common form of recurrent hypoglycaemia in neonates beyond the first week of life. Although self-resolving, treatment can be required. Consensus guidelines recommend the lower end of the diazoxide 5-15 mg/kg/day range in THI to reduce the risk of adverse events. We sought to determine if doses <5 mg/kg/day of diazoxide can be effective in THI.

DESIGN, PATIENTS, MEASURMENTS

Infants with THI (duration <6 months) were treated with low-dose diazoxide from October 2015 to February 2021. Dosing was based on weight at diazoxide start: 2 mg/kg/day in infants 1000-2000 g (cohort 1), 3 mg/kg/day in those 2000-3500 g (cohort 2) and 5 mg/kg/day in those >3500 g.

RESULTS

A total of 73 infants with THI (77% male, 33% preterm, 52% small-for-gestational age) were commenced on diazoxide at a median age of 11 days (range 3-43) for a median duration of 4 months (0.3-6.8), with no difference between cohorts. The mean effective diazoxide dose was 3 mg/kg/day (range 1.5-10); 35% (26/73) required an increase from their starting dose, including 60% (9/15) of cohort 1. There was no association between perinatal stress risk factors or treatment-related characteristics and dose increase. Adverse events occurred in 13 patients (18%); oedema (12%) and hyponatraemia (5%) were the most common. Two infants developed suspected necrotising enterocolitis (NEC); none had pulmonary hypertension.

CONCLUSION

Diazoxide doses <5 mg/kg/day are effective in THI. While the nature of the association between diazoxide and NEC was unclear, other adverse events were mild. We suggest considering starting doses as low as 2-3 mg/kg/day in THI to balance the side effect risk while maintaining euglycaemia.

Pulmonary hypertension associated with diazoxide: the SUR1 paradox

The ATP-sensitive potassium channels and their regulatory subunits, sulfonylurea receptor 1 (SUR1/Kir6.2) and SUR2/Kir6.1, contribute to the pathophysiology of pulmonary hypertension (PH). Loss-of-function pathogenic variants in the ABCC8 gene, which encodes for SUR1, have been associated with heritable pulmonary arterial hypertension. Conversely, activation of SUR1 and SUR2 leads to the relaxation of pulmonary arteries and reduces cell proliferation and migration. Diazoxide, a SUR1 activator, has been shown to alleviate experimental PH, suggesting its potential as a therapeutic option. However, there are paradoxical reports of diazoxide-induced PH in infants. This review explores the role of SUR1/2 in the pathophysiology of PH and the contradictory effects of diazoxide on the pulmonary vascular bed. Additionally, we conducted a comprehensive literature review of cases of diazoxide-associated PH and analysed data from the World Health Organization pharmacovigilance database (VigiBase). Significant disproportionality signals link diazoxide to PH, while no other SUR activators have been connected with pulmonary vascular disease. Diazoxide-associated PH seems to be dose-dependent and potentially related to acute effects on the pulmonary vascular bed. Further research is required to decipher the differing pulmonary vascular consequences of diazoxide in different age populations and experimental models.

Diazoxide-Induced Hypertrichosis in a Neonate With Transient Hyperinsulinism

Diazoxide is one of the FDA-approved pharmacologic treatments for hyperinsulinemic hypoglycemia, however, its adverse effects in infants are not well described. We reported a 37-week-old boy with the diagnosis of hypoglycemia. We started a dextrose infusion, but we used oral diazoxide, due to hypoglycemia episodes despite the increase in dextrose intake. The newborn had a normoglycemic condition after gradually increasing the diazoxide dose to 15 mg/kg/day. He was fully breastfed and discharged at 14 days of age with ongoing diazoxide. In weekly serial clinical follow-ups, the parents noticed an increase in the growth of forehead and facial hair that was diagnosed as diazoxide-induced hypertrichosis. Diazoxide was gradually tapered, and hypertrichosis continued until 1 month after dioxide discontinuation. Diazoxide use in NICU settings has increased over time. Diazoxide has many side effects, one of which is hypertrichosis. Many diazoxide side effects have been reported in adults or children and few studies have reported the prevalence of these adverse effects of diazoxide in neonates and infants.