Hormonal counterregulation and consecutive glimepiride serum concentrations during severe hypoglycaemia associated with glimepiride therapy.

Objective: To examine the release of counterregulatory hormones and consecutive glimepiride serum concentrations during severe hypoglycaemia (SH) associated with glimepiride therapy.

Methods: In nine type-2 diabetic patients [age 81+/-9 (65-93) years; diabetes duration 9+/-4 (3-15) years; initial blood glucose 33+/-16 (10-54) mg/dl (1.8+/-0.9 mmol/l); HbA1c 7.2+/-1.1 (5.6-8.7)%; creatinine clearance 49+/-33 (15-107) ml/min] who experienced SH associated with glimepiride therapy with neuroglucopenic presentation, insulin, C-peptide, glucagon, epinephrine, norepinephrine, cortisol, adenocorticotrophic hormone (ACTH), human growth hormone (HGH) and pancreatic polypeptide (PP) were determined in blood samples taken at 4-h intervals prior to and during treatment with glucose i.v. Serum from the same samples was screened for sulphonylurea-type oral antidiabetics. Glimepiride concentrations were determined by a validated atmospheric pressure chemical ionization liquid chromatographic-mass spectrometry (APCI-LC-MS) assay.

Results: Once treatment had begun, normoglycaemia was maintained; most glimepiride levels were below the limit of detection (LOD <0.01 mg/l) and further sulphonylureas could be excluded. The secretion of glucagon and epinephrine as counterregulatory hormonal responses was unaffected. In addition, protracted marked increases of cortisol and norepinephrine levels were demonstrated. Protracted stimulation of insulin and C-peptide occurred in a period of up to 24 h after SH. No significant protracted responses were observed for ACTH, HGH or PP.

Conclusion: In SH associated with glimepiride therapy, no correlation between glimepiride serum concentrations and the protracted stimulation of insulin and C-peptide was observed. The secretion of glucagon and epinephrine as counterregulatory hormonal responses was unaffected. Protracted increased release of cortisol might be a medium-term indicator of glimepiride-associated SH.