Low blood sugar, or hypoglycemia, can cause light-headedness and dizziness, states WebMD. Hypoglycemia usually occurs when blood sugar levels fall beneath 70 milligrams per deciliter. In diabetics, this can occur due to diet, exercise, certain medications and other conditions.
Other symptoms of hypoglycemia include confusion, shaking, pronounced pulse, headaches and irritability, according to WebMD. If untreated, symptoms can progress into more serious ones, such as numbness in mouth, neuromuscular difficulties, nightmares and even coma. While too much insulin can cause hypoglycemia, medications known as sulfonylureas may also contribute. Notable ones include glipizide, glimepiride and glibenclamide. Monitoring blood sugar levels more closely and making necessary adjustments are preventative measures for reducing the likelihood of hypoglycemia.