it is challenging to provide an exact figure for how much "Big Pharma" makes from medical prescriptions each year because the pharmaceutical industry is vast and diverse, comprising numerous companies with various drug portfolios. Additionally, financial data can vary from year to year and depend on several factors, including drug sales, patent expirations, new drug approvals, and market demand.
However, I can give you a general idea based on the information available up to 2021. In 2020, the global pharmaceutical market was valued at over $1.3 trillion USD in total sales. The top pharmaceutical companies, commonly referred to as "Big Pharma," contributed significantly to this revenue. Some of the largest pharmaceutical companies in terms of sales include Pfizer, Johnson & Johnson, Novartis, Roche, and Merck & Co.
Please note that these figures are approximate and subject to change. For the most up-to-date and accurate information, it is recommended to refer to financial reports, market research, and reputable sources related to the pharmaceutical industry. Additionally, the COVID-19 pandemic might have had significant impacts on pharmaceutical sales and revenue in 2020 and beyond, which would need to be taken into account when analyzing more recent data.