To report historical patterns of pharmaceutical expenditures, to identify factors that may influence future spending, and to predict growth in drug spending in 2024 in the United States, with a focus on the nonfederal hospital and clinic sectors. Historical patterns were assessed by examining data on drug purchases from manufacturers using the IQVIA National Sales Perspectives database. Factors that may influence drug spending in hospitals and clinics in 2024 were reviewed-including new drug approvals, patent expirations, and potential new policies or legislation. Focused analyses were conducted for biosimilars, cancer drugs, endocrine drugs, generics, and specialty drugs. For nonfederal hospitals, clinics, and overall (all sectors), estimates of growth of pharmaceutical expenditures in 2024 were based on a combination of quantitative analyses and expert opinion. In 2023, overall pharmaceutical expenditures in the US grew 13.6% compared to 2022, for a total of $722.5 billion. Utilization (a 6.5% increase), new drugs (a 4.2% increase) and price (a 2.9% increase) drove this increase. Semaglutide was the top drug in 2023, followed by adalimumab and apixaban. Drug expenditures were $37.1 billion (a 1.1% decrease) and $135.7 billion (a 15.0% increase) in nonfederal hospitals and clinics, respectively. In clinics, increased utilization drove growth, with a small impact from price and new products. In nonfederal hospitals, a drop in utilization led the decrease in expenditures, with price and new drugs modestly contributing to growth in spending. Several new drugs that will influence spending are expected to be approved in 2024. Specialty, endocrine, and cancer drugs will continue to drive expenditures. For 2024, we expect overall prescription drug spending to rise by 10.0% to 12.0%, whereas in clinics and hospitals we anticipate an 11.0% to 13.0% increase and a 0% to 2.0% increase, respectively, compared to 2023. These national estimates of future pharmaceutical expenditure growth may not be representative of any health system because of the myriad of local factors that influence actual spending.