Combination Medications in Diabetes Care: An Opportunity That Merits More Attention

Abstract

During the past few years, new pills have been marketed that are combinations of two separate medications. At present, these products apply to three specific treatment areas related to diabetes: diabetes itself, lipidemia, and hypertension (Table 1). Until recently, the only combination pills on the market for these disease states were combinations of diuretics and one other blood pressure medication. In the past few years, a number of newer combination diabetes and lipid medications have been released, starting with metformin-glyburide, metformin-glipizide, metformin-rosiglitazone, and lovastatin-niacin. More combinations are planned. In all cases, these combination medications are mixtures of two existing drugs that have already been marketed. In all cases thus far, providers have had extensive opportunities to gain experience with both of the combined drugs as single agents, as well as moderate experience in combining them to treat more resistant cases. Clearly, a primary motive for developing and marketing the combination tablet has been economic—an effort by the manufacturer either to extend the patent life and profitability of the key agent in the combination because patent protection was about to expire or to create a new market for an agent that would perform better than the single-agent competition. Although the economic motives for the introduction of combination products seem understandable, the benefits of these combination agents for patients and providers have not been explored in detail. One possibility, that these drugs improve patient adherence to treatment by eliminating one pill in the polypharmacy many patients face,1 has recently been challenged.2 A new study in the journal Diabetes Care suggests that, in contrast to other patient populations,3 diabetic patients do not have a reduction in adherence to their medical regimen when multiple medications are prescribed. If true, this eliminates one possible benefit of combination medications. If there is no …