The class-action lawsuit, filed anonymously by patients due to the sensitivity of their conditions, also goes after employers like Amtrak that fund prescription drug plans for their employees and chose to use CVS. The suit boils down to a few key allegations:

• Patients with a CVS drug plan previously had gone to other local, in-network specialty pharmacies to pick up their HIV/AIDS medications.
• Patients were shocked to find out their old pharmacy was out-of-network, and they were on the hook for their medications, which could easily cost more than $2,000 a month.
• CVS changed its pharmacy benefits a few years ago by requiring HIV/AIDS patients to either pick their drugs up at a CVS store or get them delivered to their homes, the suit claims.
• One plaintiff who is not home several days a week said he found his 90-day mail-ordered supply of drugs "baking in the afternoon sun."
• Patients also weren't comfortable picking up their drugs because many CVS stores lack private areas to ask questions.
• The plaintiffs said they also weren't able to opt out of CVS' options.

The major question: Other lawsuits have alleged that CVS uses anticompetitive muscle to force business partners to use certain vendors. Would Aetna customers with conditions like HIV be forced to use CVS and cut ties with their old pharmacies at the risk of paying lots of money for prescriptions out of their pockets?

CVS' response: "We have not been served with this complaint and have not had an opportunity to thoroughly review the allegations. However, (CVS') highest priority is assuring patient access to clinically appropriate drugs while managing overall health care costs for our clients. To that end, we offer our clients multiple clinical tools and pharmacy network options targeted at achieving both of these goals."