Hold metformin if the patient is at risk for dehydration (eg. vomiting, diarrhea) due to the risk of lactic acidosis
Medications that stimulate insulin secretion (eg. sulfonylureas, repaglinide, or nateglinide) should be held if the patient is at risk for hypoglycemia
Patients usually should continue their basal insulin, but may decrease or hold their bolus dosing.
Finger sticks should be checked every 2-4 hours for those on insulin, or 2-4 times per day for type II diabetics not on insulin.
References
Diabetes. Pharmacist's Letter March 2013;29(3):13-4.
