Reducing the burden of diabetes treatment: A review of low-cost oral hypoglycemic medications

BACKGROUND: The vast majority of individuals diagnosed with diabetes are low/middle income and may have access to only three of the 11 oral hypoglycemic medications (OHMs) due to cost: metformin intermediate release (IR) or extended release (ER), sulfonylureas (glimepiride, glipizide, glyburide), and pioglitazone. Sulfonylureas and pioglitazone have had significant controversy related to potential adverse events, but it remains unclear whether these negative outcomes are class-, drug-, or dose-related. OBJECTIVE: We conducted a narrative review of low-cost OHMs. METHODS: We evaluated the maximum recommended (MAX) compared to the most effective (EFF) daily dose, time-to-peak change in HbA1c levels, and adverse events of low-cost oral hypoglycemic medications. RESULTS: We found that the MAX was often greater than the EFF: metformin IR/ER (MAX: 2,550/2,000 mg, EFF: 1,500-2,000/1,500-2,000 mg), glipizide IR/ER (MAX: 40/20 mg, EFF: 20/5 mg), glyburide (MAX: 20 mg, EFF: 2.5-5.0 mg), pioglitazone (MAX: 45 mg, EFF: 45 mg). Time-to-peak change in HbA1c levels occurred at weeks 12-20 (sulfonylureas), 25-39 (metformin), and 25 (pioglitazone). Glimepiride was not associated with weight gain, hypoglycemia, or negative cardiovascular events relative to other sulfonylureas. Cardiovascular event rates did not increase with lower glyburide doses (p<0.05). Glimepiride and pioglitazone have been successfully used in renal impairment. CONCLUSIONS: Metformin, glimepiride, and pioglitazone are safe and efficacious OHMs. Prescribing at the EFF rather than the MAX may avoid negative dose-related outcomes. OHMs should be evaluated as individual drugs, not generalized as a class, due to different dosing and adverse-event profiles; Glimepiride is the preferred sulfonylurea since it is not associated with the adverse events of others in its class.