(Reuters Health) - Only 1 in 10 California pharmacies have programs to take back unused prescription opioids and just one in five give consumers accurate disposal information, according to a study that suggests drugstores could do more to help combat substance abuse.

FILE PHOTO: Tablets of the opioid-based Hydrocodone at a pharmacy in Portsmouth, Ohio, June 21, 2017. REUTERS/Bryan Woolston

For the “secret shopper”-style study, researchers called 898 pharmacies in California to inquire about the availability of take-back programs for leftover opioids and antibiotics, and find out how to safely dispose of these medicines at home.

“The danger of unused and unwanted prescription medication is substantial - from accidental childhood poisoning to pollution to intentional misuse,” said senior study author Dr. Hillary Copp of the University of California, San Francisco.

“The FDA recommends dropping off medications at a take-back site as the best option for disposal,” Copp said by email. “However, there are specific recommendations for medication disposal at home if the consumer does not have access to a take-back site.”

Just 19% of pharmacies correctly told callers they should bring unused opioids back to a drugstore or flush unused opioids down the toilet, the study found. Only 11% of pharmacies offered to take back unused opioids at their location.

With antibiotics, 47% of pharmacies correctly advised callers to return leftovers to a drugstore or to mix unused medicines with unpalatable substances like coffee grounds or kitty litter and place in a sealed container before tossing the drugs in the trash. Only 19% of pharmacies offered to take back unused antibiotics.

Tossing leftover antibiotics in the trash helps prevent people from taking them in the future for illnesses they can’t cure, which contributes to the rise of antibiotic-resistant superbugs that can’t be treated with available medicines, Copp said. Flushing antibiotics might get them into the water supply, also contributing to antibiotic resistance.

Flushing opioids, however, prevents them falling into the wrong hands and contributing to substance misuse, addiction and overdoses. Addicts might still take opioids they find in the trash, even mixed with dirt or kitty litter or other substances, Copp said.

All of the secret shoppers in the study posed as parents of children who recently had surgery. Callers asked pharmacies what to do with two leftover medications: the antibiotic Bactrim (sulfamethoxazole-trimethoprim), and liquid Hycet (hydrocodone-acetaminophen), a pain reliever containing an opioid compound.

Pharmacies gave callers the correct information about disposal of antibiotics and opioids far more often on weekdays than on weekends.

One limitation of the study is that results from California, where about 10% of the nation’s pharmacies are located, might not reflect what would happen elsewhere, the study team notes in the Annals of Internal Medicine.

Still, “the lack of consistent and clear information for patients is disturbing, particularly given risks for improper use of medications that are left in the home,” said Stacie Dusetzina, a researcher at Vanderbilt University School of Medicine in Nashville, Tennessee, who wasn’t involved in the study.

“Given the different strategies for disposal for different medicines, it seems that offering patients more opportunities to bring drugs back to pharmacies for proper disposal would help,” Dusetzina said by email.

The study results suggest that many pharmacies may be falling short as educators and as places for safe disposal, said Dr. Chana Sacks of Massachusetts General Hospital and Harvard Medical School in Boston.

“Patients may have other sources of information for questions about medication disposal - they might look it up on the internet before calling their pharmacy, for example,” Sacks, who wasn’t involved in the study, said by email. “But ideally pharmacies would be a place patients can count on to receive accurate information about all aspects of medications, including safe disposal.”

SOURCE: bit.ly/39mW6u9 Annals of Internal Medicine, online December 30, 2019.