1767-P: Intranasal Naloxone Prevents the Development of Hypoglycemia-Associated Autonomic Failure (HAAF) in Susceptible Individuals

Repeated hypoglycemic episodes can cause HAAF, i.e., blunted counter-regulatory hormone responses. We have shown that activating opiate receptors can induce HAAF in healthy participants subjected to subsequent experimentally induced hypoglycemia. However, we have noted inter-individual variability in the development of HAAF. In our current study we evaluated the effect of blocking opioid receptors with intranasal naloxone in individuals at risk for HAAF. To identify people susceptible to HAAF, fourteen nondiabetic subjects (13M, age 43.4±8.0, BMI 25.5±2.19 kg/m2) underwent two 120-minute hyperinsulinemic hypoglycemic (nadir 54 mg/dl) clamp studies on Day 1 and a third hypoglycemic clamp study on Day 2. Nine individuals developed HAAF, defined as ≥20% reduction in average epinephrine (EPI) levels (90-120 minutes) between the first and third episodes of hypoglycemia (858 ±161 vs. 494±108 pg/ml, p=0.008). The HAAF-prone subjects underwent similar 3-episode hypoglycemic studies on two subsequent occasions with hourly placebo (randomized, double-blinded) or naloxone (4 mg) on Day 1. While average EPI levels declined from the first to the third hypoglycemic episode by 42% with placebo (p=0.01), levels did not differ with intranasal naloxone (p=0.67). Similarly, plasma glucagon levels decreased significantly from the first to the third hypoglycemic episode with placebo but were maintained with naloxone (Glucagon 1st vs. 3rd episode: Placebo 31.5±8.07 vs. 21.6±5.3 mg/ml, p=0.03; Naloxone 30.5±7.42 vs. 27.0±6.9 mg/ml, p=0.41). Naloxone did not alter plasma cortisol responses or hypoglycemic symptoms. This confirms previous reports of inter-individual variability in development of HAAF. Administration of intranasal naloxone during antecedent hypoglycemia prevented HAAF in susceptible individuals. Inhaled naloxone may offer a feasible approach to ameliorate HAAF in targeted individuals at risk for hypoglycemia-related adverse events. Disclosure A. Manavalan: None. P.M. Mathias: None. S. Aleksic: None. E. Lontchi Yimagou: None. M. Carey: None. J. Moy: None. T. Patel: None. B. Kuo: None. O. Sandu: None. H. Shamoon: None. M. Hawkins: None. Funding National Institutes of Health (R01DK079974)