Global use of prescription drugs shows no sign of slowing down over the next few years, according to a new report, which projects 4.5 trillion doses will be used in 2020, with China and India driving the spike in demand.

The amount represents a 24% increase over current prescription drug use, according to an analysis released this week by the IMS Institute for Healthcare Informatics. It estimates emerging markets such as Brazil, China, India and Indonesia will represent nearly half of all growth over the next five years.

Some of those countries, such as Brazil and China, have in recent years reformed theirhealthcare systems with the aim of providing near-universal insurance coverage, and that has increased spending. Many countries have also seen their populations grow older, much like in the U.S. That has helped drive demand for drugs as the rates of noncommunicable diseases rise. More than half of the world’s population is expected to consume more than one dose per day of medicines in 2020, up from one-third in 2005.

Despite the increased use, the report forecasts a general slowdown in spending growth over the next five years, which will rise between 29% and 32% to reach $1.4 trillion in 2020, compared with the 35% increase that occurred between 2010 and 2015.

Several factors play a role in lowering spending growth over the next several years. Increased use of branded medications along with price increases will result in $163 billion in spending growth. But the report projects that price discounts and rebates, as well as a number of medications losing patent exclusivity in the coming years will result in $178 billion in reduced spending on expensive, brand-name drugs as more biosimilar drugs enter the market.

Drug use in developed markets is expected to see modest gains over the next five years. The U.S. and Europe are estimated to increase by 100 million doses in 2020.

Specialty medications, which have been at the center of debate in recent months because of their high cost, are expected to make up 28% of global spending on medication in 2020, up from 26% in 2015. Developed markets will continue to outpace spending on specialty drugs, with such products making up 36% of the market in those countries in 2020 compared with 12% in emerging markets.

The IMS report projects more than 225 new drugs will be introduced by 2020, with one-third of those products being oncology medications.

“During the next five years, we expect to see a surge of innovative medicines emerging from R&D pipelines, as well as technology-enabled advances that will deliver measurable improvements to health outcomes,” said Murray Aitken, executive director of the IMS Institute for Healthcare Informatics, in a released statement. “With unprecedented treatment options, greater availability of low-cost drugs and better use of evidence to inform decisionmaking, stakeholders around the world can expect to get more ‘bang for their medicine buck’ in 2020 than ever before.”