Lower Drug Costs for Families Act This bill applies certain Medicare prescription drug rebate requirements to prescription drugs that are available under private health insurance. Current law requires drug manufacturers to issue rebates to the Centers for Medicare & Medicaid Services for brand-name drugs without generic equivalents under Medicare that (1) cost $100 or more per year per individual, and (2) for which prices increase faster than inflation. Manufacturers that fail to comply are subject to civil penalties. The bill applies these requirements to prescription drugs that are available in the commercial market under private health insurance. It also indexes rebate calculations to drug prices in 2016 (as opposed to 2021).