Amazon is adding a prescription drug discount programme to its growing health care business. The retail giant said Tuesday that it will launch RxPass, a subscription service for customers who have Prime memberships. Amazon said people will pay USD 5 a month to fill as many prescriptions as they need from a list of about 50 generic medications, which are generally cheaper versions of brand-name drugs. The company said the flat fee could cover a list of medications like the antibiotic amoxicillin and the anti-inflammatory drug naproxen. Sildenafil also made the list. It’s used to treat erectile dysfunction under the brand name Viagra and also treats a form of high blood pressure. Amazon sells a range of generic drugs through its pharmacy service. Some already cost as low as USD 1 for a 30-day supply, so the benefit of this new programme will vary by customer. The new programme doesn’t use insurance, and people with government-funded Medicaid or Medicare coverage are not eligible. It will be available in 42 states and Washington, D.C. at launch. Any programme that gets low-cost generic drugs to more patients “is a good thing,” said Karen Van Nuys, an economist who studies drug pricing at the University of Southern California. But she added that she wasn’t sure how much of an impact RxPass will have.