WASHINGTON — Federal officials have approved a new type of pain pill designed to eliminate the risks of addiction and overdose associated with opioid medications like Vicodin and OxyContin.

The U.S. Food and Drug Administration said last week it approved Vertex Pharmaceuticals’ Journavx for short-term pain that often follows surgery or injuries.

It’s the first new pharmaceutical approach to treating pain in more than 20 years, offering an alternative to both opioids and over-the-counter medications like ibuprofen and acetaminophen.

But the medication’s modest effectiveness and lengthy development process underscore the challenges of finding new ways to manage pain.

Studies in more than 870 patients with acute pain due to foot and abdominal surgeries showed Vertex’s drug provided more relief than a dummy pill, but didn’t outperform a common opioid-acetaminophen combination pill.

“It’s not a slam dunk on effectiveness,” said Michael Schuh of the Mayo Clinic, a pharmacist and pain medicine expert who was not involved in the research. “But it is a slam dunk in that it’s a very different pathway and mechanism of action.

“So, I think that shows a lot promise.”

The new drug will carry a list price of $15.50 per pill, making it many times more expensive than comparable opioids, which are often available as generics for $1 or less.

Opioids reduce pain by binding to receptors in the brain that receive nerve signals from different parts of the body. Those chemical interactions also give rise to opioids’ addictive effects.

Vertex’s drug works differently, blocking proteins that trigger pain signals that are later sent to the brain.

The initial concept to focus on pain-signaling proteins came out of research involving people with a rare hereditary condition that causes insensitivity to pain.

Vertex has attracted interest from Wall Street for its ambitious drug pipeline that involves winning FDA approval for multiple drugs across several forms of chronic pain, a bigger financial opportunity than acute pain.

But the share price plummeted in December when Vertex reported disappointing mid-stage results in a study of patients with chronic nerve pain affecting the lower back and legs.

The drug didn’t perform significantly better than placebo, the research found.