Seniors Prescription Drug Relief Act This bill establishes and alters several programs and requirements relating to the prices of prescription drugs under Medicare. For example, the bill caps annual out-of-pocket spending under the Medicare prescription drug benefit. It also establishes (1) a program under which drug manufacturers must, subject to civil penalties, provide discounts for covered drugs for beneficiaries who have incurred costs above the annual deductible; and (2) a process through which certain beneficiaries may have their monthly out-of-pocket costs capped and paid in monthly installments.