Prescription drugs are big business, and not just for the makers of those drugs. Prescription dispensing revenues hit a record high 0f $46 billion in 2019, according to the Drug Channels Institute's 2020 Economic Report on U.S. Pharmacies and Pharmacy Benefit Managers. According to this year's report, a portion of that growth is attributable to the rise of specialty drug sales from PBMs, including Caremark, Express Scripts, OptumRx and Humana. For these companies, specialty drugs made up approximately 60 percent of revenues. Related: 6 ways Amazon could up-end the pharmacy business Another trend? Big pharmacies continue to get bigger, and smaller pharmacies, such as those found in local grocery stores, continue to become more scarce. The top 15 pharmacies accounted for three-quarters of revenue in 2019. Meanwhile, CVS and Walgreens picked up new revenue by acquiring eight smaller chains between them. Among the report's other key findings:

• Insurers, PBMs and specialty pharmacies continue to integrate vertically, giving them more control over how and where drugs are accessed.
• Retail pharmacy growth continues to slow under increased competition, and the number of retail pharmacies continues to decrease.
• Rebates and discounts paid by manufacturers totaled $175 billion.
• Outside investors such as Amazon continue to look for new ways to disrupt how prescription drugs are dispensed.

In addition, the prescription drug industry faces ongoing scrutiny from federal and state regulators, though no significant action has been taken to disrupt the industry. Amid all of these threats and opportunities, which pharmacies are still leading the way in terms of revenues? Check out the slideshow above to find out. Read more: 

• The decline of the pharmacy-grocer
• Consumers may hate drug costs, but they like their pharmacies
• Amazon teams up with Novartis on pharma delivery