Generic Diabeta drug side effects may include nausea, heartburn, stomach fullness, and weight gain, persistent sore throat or fever, easy bleeding or bruising, stomach pain, yellowing eyes or skin, dark urine, unusual tiredness or weakness, unusual or sudden weight gain, mental/mood changes, swelling of the hands or feet, seizures, low blood sugar with symptoms that include chills, cold sweat, blurred vision, dizziness, drowsiness, shaking, rapid heart rate, weakness, headache, fainting, tingling of the hands or feet, or hunger. An allergic reaction to Diabeta is improbable, but immediate medical attention should be sought if it there is rash, itching, swelling, dizziness, trouble breathing.