Do not give up taking it except on the advice of your doctor. If you take it only once a day, take it at bedtime to reduce daytime sleepiness. Consult your doctor before breast-feeding. Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. If any of these effects persist or worsen, notify your doctor or pharmacist promptly. Monitor your blood sugar levels regularly and tell your doctor of the results. If you see that it is near the time for the next dose, skip the missed dose and resume your usual dosing schedule. Limit alcoholic beverages.