Exceptions to the inpatient insulin “rule”: When an oral agent may make sense
Although severity of illness, planned or unplanned procedures, and changes from usual dietary patterns may limit the utility of some oral agents, no large studies have investigated the impact of oral diabetes medications on inpatient outcomes.1 For a patient who has excellent outpatient glycemic control and is not critically ill, continuation of some or all oral agents may be appropriate. Consider the following:
Metformin. This agent has the benefit of not causing hypoglycemia and of facilitating weight loss. Metformin is, however, contraindicated in patients with renal insufficiency, congestive heart failure, cardiovascular collapse, acute myocardial infarction, and septicemia.24
Despite the warning, metformin is often used in patients with these contraindications. A recent systematic review of more than 17,000 patients taking the drug did not uncover a single case of lactic acidosis.25 With appropriate monitoring, metformin may be a useful inpatient treatment for some patients.
Sulfonylureas. These agents should be limited in the inpatient setting because of their long action and propensity to cause hypoglycemia. In addition, some questions have arisen about the safety of these medications in patients with vascular disease and acute cardiac events.23,26 Despite this, there is no rigorous data to specifically advise against keeping inpatients with diabetes on sulfonylureas.
Thiazolidinediones. These agents should be used with caution in the inpatient setting. Although they have relatively few acute adverse effects, they have been shown to increase intravascular volume and have the potential to exacerbate congestive heart failure.27
Take advantage of bedside conversations. An inpatient stay offers physicians and patients the opportunity to work together to fine-tune components of the diabetic regimen.23 Make the most of these opportunities. In addition, once the patient goes home, you’ll need to ensure close follow-up to reconcile the differences between home self-management and the controlled hospital environment.
Correspondence
Donald R. Woolever, MD, Family Medicine Residency Program, Central Maine Medical Center, 76 High Street, Lewiston, ME 04240; woolevra@cmhc.org.