For anyone tracking the pharmaceutical industry, the question of which drug is the 'most sold' is complex and revealing. The answer highlights the fundamental split in the market: brand-name biologics and cancer treatments that generate billions in revenue versus low-cost generic pills that are dispensed in immense volumes to millions of patients. While blockbuster specialty drugs capture headlines for their extraordinary profits, generic medications form the backbone of the American healthcare system based on sheer prescription volume.
The Most Sold Drug by Revenue: A Story of Specialty Biologics
When measuring by revenue, the list of top-selling drugs in the US and globally is dominated by highly expensive, often cutting-edge, treatments. These are typically biologics, which are complex drugs derived from living organisms, or targeted therapies for chronic or serious diseases like cancer.
Keytruda: The oncology king of 2024
In 2024, Merck's oncology drug Keytruda (pembrolizumab) cemented its position as a top-grossing drug, with nearly $29.5 billion in global sales. Approved for numerous cancer indications, this immunotherapy drug works by helping the body's immune system fight cancer cells. Keytruda's success is a testament to the high-value, high-cost nature of modern oncology treatments and the significant investment in research and development that drives their creation.
The rise and fall of Humira
For nearly a decade, Humira (adalimumab) held the title of the world's best-selling drug, peaking at over $21 billion in annual sales in 2022. This blockbuster biologic treats a range of autoimmune diseases, including rheumatoid arthritis and Crohn's disease. However, with its patent expiration in the US in 2023, several biosimilar competitors entered the market. This increased competition led to a sharp decline in Humira's sales, illustrating the dramatic impact of patent cliffs on the revenue leaders in the pharmaceutical world.
The GLP-1 phenomenon: Ozempic and beyond
New players are rapidly reshaping the revenue charts. Novo Nordisk's Ozempic (semaglutide), originally for type 2 diabetes, saw its sales surge to approximately $18.7 billion in 2024, fueled by high demand and expanded use for weight management. Along with its counterpart for weight loss, Wegovy, and competitor Mounjaro, these GLP-1 agonists represent a new wave of blockbuster success, though they also face increasing regulatory and pricing scrutiny.
The Most Sold Drug by Volume: The Reign of Generics
When the measure shifts to the number of prescriptions filled, a different set of medications rises to the top. These are typically generic drugs for common, chronic conditions that are used by millions of Americans.
Atorvastatin: The generic prescription leader
One of the most consistently prescribed drugs by volume in the US is atorvastatin, the generic version of Lipitor. This statin medication is used to lower high cholesterol and reduce the risk of cardiovascular disease. The widespread prevalence of high cholesterol means atorvastatin is prescribed to millions of patients annually, solidifying its place as a volume leader long after its brand-name version lost patent exclusivity.
Other high-volume generic giants
Many other generic drugs also consistently rank high in prescription volume due to their role in managing widespread chronic illnesses. These include:
- Metformin: An antidiabetic medication for managing blood sugar levels in patients with type 2 diabetes.
- Levothyroxine: A hormone medication used to treat hypothyroidism and thyroid-related conditions.
- Lisinopril: An ACE inhibitor commonly prescribed for high blood pressure and heart failure.
A Comparison of Blockbusters vs. Generics
| Feature | Most Sold by Revenue (e.g., Keytruda) | Most Sold by Volume (e.g., Atorvastatin) |
|---|---|---|
| Measurement Metric | Total dollar value of sales | Number of prescriptions dispensed |
| Drug Type | Often complex biologics or specialty drugs | Generally small-molecule generics |
| Cost | High (tens of thousands or more per course) | Low (often under $100 for a month's supply) |
| Patent Protection | Brand-name drugs with active patents or exclusivity | Generic versions after patent expiration |
| Market Dynamics | Driven by medical innovation, R&D, and pricing | Driven by market volume, affordability, and prevalence |
| Primary Driver | High cost per unit | High number of units sold |
Factors Driving the American Pharmaceutical Market
Several factors shape the contrasting stories of revenue and volume leaders in the US pharmaceutical market:
- Research & Development (R&D): The high costs and long timelines associated with developing innovative specialty drugs mean companies must charge high prices to recoup their investments. The market rewards risk-taking in R&D, especially for treatments targeting complex diseases like cancer.
- Patent Expiration and Biosimilars: A brand-name drug's sales typically peak before its patent expires. The loss of exclusivity, as seen with Humira, opens the door for lower-priced generic and biosimilar competition, which can dramatically erode the originator's market share.
- Prevalence of Chronic Disease: The high prescription volumes for generics like atorvastatin and metformin are driven by the large number of Americans living with chronic conditions like high cholesterol, high blood pressure, and type 2 diabetes.
- Cost-Conscious Healthcare System: Payers, including insurance companies and pharmacy benefit managers, actively promote generic and biosimilar alternatives to control costs. This pressure shifts prescription volume away from expensive brand-name drugs once generics become available.
The Shifting Landscape of US Drug Sales
The pharmaceutical landscape is in constant flux. The rise of new drug classes, such as GLP-1 agonists, and the continued maturation of specialty areas like oncology and immunology drive blockbuster revenue figures. Meanwhile, the generic market remains a stable force, ensuring that essential and affordable treatments are available to the vast majority of the population. The interplay between these two segments—one focused on innovation and high-value treatments, the other on volume and affordability—defines the American pharmaceutical marketplace.
Conclusion
Ultimately, there is no single answer to the question, "What is the most sold drug in the US?" It depends on the definition. By revenue, the most sold drug in recent years has been a high-cost biologic like Keytruda, reflecting the focus on innovative, expensive specialty therapies. By volume, the leader is a widely used and affordable generic drug such as atorvastatin, representing the backbone of chronic disease management. A complete picture of the US pharmaceutical market requires an understanding of both metrics and the market dynamics that drive them.
