(Reuters Health) - Brand-name medicines that combine multiple drugs into a single pill may be more expensive than buying each drug separately, a U.S. study suggests.

Researchers examined data collected from 2011 to 2016 on 1,500 medicines that accounted for the highest total spending for Medicare Part D drug plans in 2015. This included 29 brand-name combination pills with generic alternatives available.

For the ten most costly brand-name combo pills, Medicare could have spent $2.7 billion less if generic alternatives had been prescribed instead, researchers estimate.

“These brand-name combination pills cost far more than sum of their parts,” said study leader Dr. Chana Sacks of Brigham and Women’s Hospital in Boston.

“The price of brand-name combination drugs, like all medications in the U.S., are not determined based on the magnitude of the clinical benefit or the costs of research and development; rather prices are set by the manufacturer based on what the market will bear,” Sacks said by email.

In 2016, Medicare spent $303 million on brand-name combo pills when identical doses of the generics sold separately would have cost $68 million, her team reports in JAMA.

That year, Medicare also spent $232 million on brand-name combo pills that would have cost $13 million if patients got generic drugs at different doses.

And, Medicare spent $491 million on brand-name combo pills when patients could have gotten therapeutically equivalent generics for $20 million.

Brand-name combo pills do have some advantages. Chief among them is that patients who take multiple drugs for chronic health problems can cut back on the number of pills they need to buy and remember to take.

But these combo pills don’t work better than the individual medicines. Therefore, they’ve been controversial because of their potential to drive up health care spending.

Epzicom, a combination of abacavir and lamivudine to treat HIV, resulted in estimated excess Medicare spending of about $106 million in 2016, researchers estimated, based on its cost compared with the separate generic pills.

Zegerid, a combination of the stomach medicines omeprazole and sodium bicarbonate, resulted in estimated excess spending of $28.1 million that year.

Percocet, a painkiller containing oxycodone and acetaminophen, resulted in estimated excess spending of $42.8 million in 2016.

“One surprising finding was that this held true even for brand-name combination pills that have generic versions of the combination pill,” Sacks said. “For example, Medicare reported spending more than $14 for each dose of brand-name Percocet . . . despite the existence of a generic combination oxycodone/acetaminophen product.”

The study didn’t look at how much patients paid at the drugstore, so it’s not clear how much of the excess cost of brand-name combo pills came from their pockets.

Researchers also lacked data on why combo pills were prescribed. Sometimes there may be good reasons to use a specific drug rather than a substitute, the study authors note.

When individual drugs are not available in the doses used for a combination product, it may be harder to find substitutes, said Stacie Dusetzina of Vanderbilt University School of Medicine in Nashville, Tennessee, who wasn’t involved in the study.

But even when combination pills might be more convenient for patients, the cost may not be worth it, Dusetzina, who wasn’t involved in the study, said by email.

“This benefit can be quickly erased if patients have a hard time affording the combination product,” Dusetzina said. “For patients who are using a combination product and finding that they are not affordable, they should ask their pharmacist if there is a cheaper option.”

SOURCE: bit.ly/2nXY2CQ JAMA, online August 21, 2018.