FlexPen for the delivery of insulin: accuracy, injection force and patient preference.

FlexPen is a widely used, prefilled, insulin-delivery pen for patients with Type 1 or Type 2 diabetes. Well-designed trials suggest that FlexPen is more accurate than other prefilled pens at high, medium and low doses. Furthermore, FlexPen is preferred to the vial-and-syringe method by patients, but comparisons of patient preference for modern pens are currently lacking. Next Generation FlexPen has similar accuracy to FlexPen but has improved patient perception. FlexPen improves adherence and reduces costs compared with the vial-and-syringe method, but the relative adherence and/or cost benefits of different pens are unknown. Important improvements in Next Generation FlexPen include: a significantly reduced injection force (that is lower than the injection force of other prefilled pens) and clearer labeling for insulin-type differentiation. Current evidence suggests that FlexPen and Next Generation FlexPen are an attractive choice when considering insulin-delivery methods.