Some of the best-selling prescription drugs have seen huge price spikes in recent years.

Use the lookup tool to reveal how costs for some of the most popular medications have changed over time.

Data comes from the Centers for Medicare and Medicaid Services. Prices reflect total spending by the Medicare Part D program in 2015 for each recipient of the prescription drug. The amount of the cost shared by the patient varies, but in most cases is around 5 percent to 20 percent of the total spending, the data shows.