Curbside Consults

VOL 107 / NO 7 / JUNE 2000 / POSTGRADUATE MEDICINE

Oral antidiabetic agents safe with renal disease?

Family physician, Indiana

A: Use of oral antihyperglycemic drugs in older patients with renal insufficiency requires careful consideration. It is well known that metformin hydrochloride (Glucophage) is contraindicated in patients with renal insufficiency (ie, serum creatinine level >1.5 mg/dL). However, there are no such restrictions on other oral antihyperglycemic agents, including other insulin sensitizers.

It is perfectly appropriate and quite efficacious to combine insulin-sensitizing agents that work by different mechanisms (eg, metformin combined with rosiglitazone maleate [Avandia] or pioglitazone hydrochloride [Actos]) (1). The caution when doing so is to monitor findings of liver function tests monthly for the first 6 months and every 6 months thereafter. No renal toxicity is associated with such a combination, and renal function does not need to be closely monitored. Moreover, recent data suggest that rosiglitazone and pioglitazone may contribute to small reductions in blood pressure. In addition, rosiglitazone may lower microalbuminuria.

If further glucose control is needed, agents that work by yet a different mechanism can certainly be used in conjunction with these others. For example, acarbose (Precose) works by a different mechanism that is complementary to the other agents, but it may not be as well tolerated because of gastrointestinal side effects.

Remember that dietary management is the key to glucose control in patients with type 2 diabetes, and weight loss is the single best measure. In addition, drugs that worsen insulin resistance (eg, moderate- to high-dose beta blockers, high-dose diuretics) should be avoided. Use of alternative agents (eg, alpha blockers, angiotensin-converting enzyme inhibitors) to control blood pressure ensures an optimal environment to control glucose levels.

George Bakris, MD
Departments of Preventive and Internal Medicine
Rush-Presbyterian-St Luke's Medical Center, Chicago

Reference

1. Riddle MC. Oral pharmacologic management of type 2 diabetes. Am Fam Physician 1999;60(9):2613-20

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