The term “top-selling drug” refers to two distinct measures of market dominance: the monetary value of sales (revenue) or the quantity of prescriptions dispensed (volume). These two metrics paint vastly different pictures, contrasting high-priced specialty treatments with low-cost, widely accessible therapies. While volume indicates how many people receive a medication, revenue determines the financial power and strategic direction of pharmaceutical companies. This analysis focuses primarily on financial blockbusters that command billions in annual sales, while also exploring essential, high-volume medications.
Understanding the Metrics: Revenue Versus Volume
The difference between revenue and volume hinges on price and market exclusivity. Revenue leaders are typically expensive, branded specialty drugs, often biologics, that treat smaller patient populations but carry a high price tag. These products generate billions of dollars for their manufacturers. In contrast, volume leaders are universally low-cost generic drugs that treat common, widespread conditions. These generics are inexpensive per dose but are dispensed hundreds of millions of times, making them commonplace without generating blockbuster revenue.
The World’s Top-Selling Drugs by Revenue
The list of the world’s most financially successful drugs is dominated by complex, high-price therapies for chronic and life-threatening conditions. Merck’s Keytruda, an anti-PD-1 immunotherapy for various cancers, has become the undisputed revenue leader, with sales projected to reach nearly $30 billion in 2024. Its success is driven by approval across more than 40 different oncology indications, making it a foundational treatment in modern cancer care and solidifying its position as the largest pharmaceutical product globally.
Close behind are drugs that address major chronic diseases with targeted, innovative mechanisms. Novo Nordisk’s Ozempic, a glucagon-like peptide-1 (GLP-1) receptor agonist used for type 2 diabetes, is projected to command sales of approximately $17.5 billion in 2024, reflecting the massive and growing market for metabolic treatments. Eliquis, a blood thinner from Bristol Myers Squibb and Pfizer, is another high-revenue product, with 2024 sales projected at over $20 billion, due to its widespread use in preventing stroke and blood clots in high-risk patients.
Immunology treatments also feature prominently, with Dupixent (Sanofi/Regeneron) for inflammatory conditions like severe asthma and eczema projected to achieve around $14.1 billion in sales. The landscape is changing rapidly, demonstrated by the decline of AbbVie’s Humira, which was the world’s top-seller for six consecutive years. Humira’s revenue fell significantly, projected to be around $8.9 billion in 2024, as it faced intense competition from lower-cost biosimilar alternatives. Similarly, Johnson & Johnson’s Stelara, used for inflammatory diseases, is bracing for revenue erosion as its market exclusivity expires.
Factors Driving High Pharmaceutical Revenue
The ability of a drug to generate tens of billions in revenue stems from a combination of scientific complexity and legal market protection. Many of the top-selling drugs, such as Keytruda and Humira, are biologics, large-molecule medicines derived from living cells rather than chemical synthesis. Developing a biologic is a highly capital-intensive endeavor, with manufacturing costs estimated to be five to ten times higher than those for small-molecule drugs. This complexity requires specialized facilities and personnel, justifying a higher initial price point.
The second major driver is market exclusivity, which grants the manufacturer a temporary monopoly. This protection is often prolonged beyond the initial patent through a “patent thicket,” where companies file numerous secondary patents on minor aspects of the drug. This strategy delays the entry of generic or biosimilar competition, allowing the brand-name drug to maintain elevated prices for years. After the loss of exclusivity, a drug’s revenue can plunge by 80 to 90 percent within the first year as cheaper alternatives flood the market.
Drugs That Sell the Most by Volume
While blockbuster revenue drugs capture the financial spotlight, the highest-volume drugs are the ubiquitous, low-cost generics that form the foundation of public health globally. These medications are widely accessible because they treat highly prevalent conditions and their original patents have long expired, opening the door to intense generic competition. The sheer quantity of these prescriptions dwarfs the sales volume of any branded specialty drug.
Common Chronic Condition Treatments
The most prescribed medications globally treat widespread chronic conditions such as diabetes, hypertension, and high cholesterol. Metformin, the first-line treatment for type 2 diabetes, is consistently one of the most dispensed medications, with over 85 million prescriptions filled in the U.S. in 2023 alone. Similarly, statins like atorvastatin (generic for Lipitor) and common blood pressure medications like lisinopril are dispensed in massive volumes to manage cardiovascular risk factors. These generic therapies represent treatments that millions of people rely on daily, costing only a few dollars per prescription.
High-Volume Consumer Pain Relievers
OTC pain relievers also contribute significantly to high-volume sales globally due to their immediate accessibility. Acetaminophen, the active ingredient in Tylenol, is a market leader, with global sales exceeding 150 million units annually. Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen are also purchased in high volumes, reflecting their status as household staples for managing headaches, fever, and minor aches. The vast scale of consumer purchases places these products among the highest-volume drugs sold worldwide.
Widely Prescribed Antibiotics
Antibiotics are another category defined by high volume, as they are essential for treating common acute bacterial infections. Amoxicillin remains the most frequently prescribed antibiotic, constituting a significant percentage of the nearly 270 million total antibiotic prescriptions dispensed in the U.S. each year. The high volume of antibiotics reflects their importance in managing common respiratory, skin, and ear infections, making them a cornerstone of infectious disease treatment.
Major Therapeutic Areas Dominating Sales
The therapeutic areas that drive the highest revenue require long-term, specialized, and complex treatments. Oncology, or cancer treatment, is the largest area by sales, anchored by immunotherapies like Keytruda. This category demands high pricing due to its sophisticated mechanism and the shift toward personalized, targeted therapies.
Immunology, covering autoimmune and inflammatory diseases, is the second major area, with drugs like Humira and Dupixent generating immense sales. These chronic conditions require continuous, long-term use of expensive biologic therapies to manage inflammation. The third area experiencing explosive growth is Metabolic Disorders, driven by the GLP-1 class of drugs for type 2 diabetes and weight management. The widespread prevalence of these conditions, combined with the high cost of new injectable therapies, has made metabolic drugs a dominant force.
The Future of the Blockbuster Market
The pharmaceutical market is entering a transformative period shaped by patent expirations and the emergence of new technologies. The impending “patent cliff” for major revenue generators like Keytruda and Stelara is set to disrupt the market, as biosimilars are expected to erode billions in sales revenue. Companies are attempting to mitigate this by developing new formulations, such as a subcutaneous version of Keytruda, to maintain market share.
The next generation of blockbusters is already emerging, led by the GLP-1 agonists, including Ozempic and its weight-loss counterpart, Wegovy. These drugs are demonstrating massive sales growth potential that could soon challenge the dominance of oncology products. As these metabolic drugs gain expanded approvals for cardiovascular benefits, their patient base and financial impact are expected to expand dramatically, reshaping the definition of a top-selling drug.