The workers compensation industry is leaning on anti-inflammatory drugs as it seeks to move away from opioids as a prescription for pain for injured workers.

But some medical experts are concerned that this shift could also lead to overprescribing, overutilization and serious side effects such as gastrointestinal bleeding and liver and heart problems.

Known in the marketplace as non-steroidal anti-inflammatory drugs, this class of pain relievers aims to reduce inflammation, a common cause of musculoskeletal pain. NSAIDs, as they are dubbed, come in prescription strengths with generic names such as celecoxib, etodolac and diflunisal.

They are also sold in over-the-counter varieties under common household names that include Advil, Aleve and Motrin or generic names such as ibuprofen and even aspirin.

“We are shifting toward (NSAIDs), and there are side effects we are concerned with,” said Reema Hammoud, Southfield, Michigan-based director of clinical pharmacy for Sedgwick Claims Management Services Inc.

“We are on guard,” Nikki Wilson, Omaha, Nebraska-based pharmacy product manager for Coventry Workers Comp Services, said of the industry’s trend toward nonopioid pain medications.

“We know there needs to be a lot of education on the front end” of prescribing anti-inflammatory drugs, she added.

Most in the medical community have recently put NSAIDs in another category: safer than opioids.

The California closed drug formulary for injured workers launched on Jan. 1 has moved all opioids into the “nonexempt” category, meaning a utilization review is required beyond a four-day supply. Yet the formulary allows most pain-relieving anti-inflammatory drugs, classifying the drugs as “exempt” from a utilization review, meaning doctors can generally prescribe them for pain without regulatory oversight.

The formulary lists 28 NSAIDs, with four that are nonexempt and come with restrictions for prescribing to injured workers, according to the drug list.

“Most state formularies and treatment guidelines recommend NSAIDs first,” said Dr. Brigette Nelson, Scottsdale, Arizona-based senior vice president of workers compensation clinical management at Express Scripts Holding Co. “Yet they are not innocuous drugs.”

Those managing workers comp claims and injured workers’ prescriptions say a close examination of side effects has some putting the brakes on NSAIDs, or at least treading cautiously.

“The side effects are not fatal if you know what you are doing,” Ms. Wilson said.

The U.S. Food and Drug Administration’s list of 19 side effects includes heart attack, stroke, high blood pressure, kidney and liver failure and stomach ulcers. The longer NSAIDs are taken, the higher the risk of developing or worsening such conditions, according to the FDA.

For example, a person with a heart condition should take the “lowest dose possible,” said Ms. Wilson, who added, “or not at all.” In some cases, she said, the patient is “left with opioids” as a safer option for treating pain.

“You have to look at all the patient factors and evaluate that patient to prevent these side effects,” said Ms. Hammoud, adding that some risks can be mitigated with other medications, such as protective agents for the gastrointestinal tract. “There are ways to prescribe them where they are not dangerous.”

Most prescribers are aware of what to do and how to prescribe, but the patients themselves can raise the risk by being uninformed, Dr. Nelson said.

“Prescribers are careful, but consumers are not,” said Dr. Nelson, who said some of the risk in comp — and the delay of recovery and exacerbation of health problems that come with side effects — can be out of the industry’s hands because they don’t know the patients are mixing medications.

Undisclosed NSAID drug combinations increase the risk exponentially, experts say. That’s when an injured worker suffering from pain takes both a prescription formula and an over-the-counter NSAID, unaware that mixing the two can put a patient on the fast track to more serious side effects.

“I think one of the things that we’ve discovered is that people know what they are taking, they know what the product is called, but they don’t know what it is or what’s in it,” said David Kaufman, a Boston University epidemiologist and researcher who in 2017 conducted a study of 1,326 ibuprofen users, including some who also took prescription formulas in conjunction with what they purchased over the counter. “If they don’t know it’s an NSAID and they don’t know they shouldn’t take more than one NSAID at a time, then they get into trouble.”

Mr. Kaufman had patients keep a seven-day diary on medications and, upon inspection, found that “most did not recognize all products taken as NSAIDs.”

“We can prevent so much by educating our patients and letting them know that these are chemicals and we have to be careful,” said Ms. Hammoud.

“Especially with long-term use, we don’t want to see anybody taking anything long term. Everything comes with side effects,” she said.