Gabapentin-Induced Hypoglycemia in a Patient With Pre-Diabetes: A Case Report and Review of the Literature

Gabapentin, a γ-aminobutyric acid (GABA) analogue, is widely prescribed for neuropathic pain and partial seizures. While common adverse effects include somnolence and dizziness, hypoglycemia is rarely reported. A 76-year-old woman with hypertension, dyslipidemia, hypothyroidism, and pre-diabetes (HbA1c 6%) developed recurrent symptomatic hypoglycemia shortly after starting gabapentin 300 mg once daily for neuropathic pain. Within two days, she experienced dizziness, sweating, and fatigue with capillary glucose readings as low as 2.4 mmol/L, confirmed on laboratory chemistry. Investigations revealed inappropriately elevated insulin and C-peptide with negative ketones, consistent with a non-ketotic hyperinsulinemic hypoglycemic state. Other causes, including insulinoma, factitious hypoglycemia, and adrenal insufficiency, were excluded. The Naranjo Adverse Drug Reaction Probability Scale score was 7, indicating a probable relationship between gabapentin and the hypoglycemia. Gabapentin was discontinued after three doses. The hypoglycemic episodes resolved within several days, and no further events occurred during hospital observation, a 72-h fast, or continuous glucose monitoring at follow-up. This case highlights gabapentin as a potential cause of clinically significant hypoglycemia, even in patients without overt diabetes. Clinicians should remain aware of this underrecognized adverse effect, especially in elderly patients.