The opioid overdose antidote naloxone, cleared by the Food and Drug Administration last year for over-the-counter sales, is not always easy to find in pharmacies.

NBC News searched for naloxone, sold as Narcan, in 64 stores in 15 states and Washington, D.C. over three weeks in February. The stores included major chain drug stores, independent pharmacies, supermarkets, big-box chains, gas stations and convenience stores.

The investigation found Narcan boxes were stored in different locations, including on or behind the pharmacy counter, in the pain medication aisle or behind the front register. Sometimes, a customer would have to ask for help to find it. In one store, they were in a locked case marked “COVID tests.”

Most of the major drugstores and big-box store pharmacies carried Narcan. None of the gas stations or convenience stores did.

The maker of Narcan, Emergent BioSolutions, says that since the launch of the over-the-counter version of the medication last fall, it can be purchased at more than 32,000 mass, drug, grocery and online retailers and e-commerce sites. In 2023, the company distributed more than 20 million doses of the antidote, both over-the-counter and prescription, in the U.S. and Canada, the company said.

Almost all stores visited by NBC News priced over-the-counter Narcan at around $45. Several stores were selling it for $49.99.