The number of people hospitalized because of amphetamine use is skyrocketing in the United States, but the resurgence of the drug largely has been overshadowed by the nation’s intense focus on opioids.

Amphetamine-related hospitalizations jumped by about 245 percent from 2008 to 2015, according to a recent study in the Journal of the American Medical Association. That dwarfs the rise in hospitalizations from other drugs, such as opioids, which were up by about 46 percent. The most significant increases were in Western states.

The surge in hospitalizations and deaths due to amphetamines “is just totally off the radar,” said Jane Maxwell, an addiction researcher. “Nobody is paying attention.”

Doctors see evidence of the drug’s comeback in emergency departments, where patients arrive agitated, paranoid and aggressive. Paramedics and police officers see it on the streets, where suspects’ heart rates are so high that they need to be taken to the hospital for medical clearance before being booked into jail. And medical examiners see it in the morgue, where in a few states, such as Texas and Colorado, overdoses from meth have surpassed those from the opioid heroin.

Amphetamines are stimulant drugs, which are both legally prescribed to treat attention deficit hyperactivity disorder and produced illegally into methamphetamine. Most of the hospitalizations in the study are believed to be due to methamphetamine use.

Commonly known as crystal meth, methamphetamine was popular in the 1990s before laws made it more difficult to access the pseudoephedrine, a common cold medicine, needed to produce it. In recent years, law enforcement officials said, there are fewer domestic meth labs and more meth is smuggled in from south of the border.

As opioids become harder to get, police said, more people have turned to meth, which is inexpensive and readily available.

The federal government estimates that more than 10,000 people died of meth-related drug overdoses last year. Deaths from meth overdose generally result from multiple organ failure or heart attacks and strokes, caused by extraordinary pulse rates and skyrocketing blood pressure.

In California, the number of amphetamine-related overdose deaths rose by 127 percent from 456 in 2008 to 1,036 in 2013. At the same time, the number of opioid-related overdose deaths rose by 8.4 percent from 1,784 to 1,934, according to the most recent data from the state Department of Public Health.

“It taxes your first responders, your emergency rooms, your coroners,” said Robert Pennal, a retired supervisor with the California Department of Justice. “It’s an incredible burden on the health system.”

Costs also are rising. The JAMA study, based on hospital discharge data, found that the cost of amphetamine-related hospitalizations had jumped from $436 million in 2003 to nearly $2.2 billion by 2015. Medicaid was the primary payer.

“There is not a day that goes by that I don’t see someone acutely intoxicated on methamphetamine,” said Dr. Tarak Trivedi, an emergency room physician in Los Angeles and Santa Clara counties. “It’s a huge problem, and it is 100 percent spilling over into the emergency room.”

Trivedi said many psychiatric patients are also meth users. Some act so dangerously that they require sedation or restraints. He also sees people who have been using the drug for a long time and are dealing with the downstream consequences.

In the short term, the drug can cause a rapid heart rate and dangerously high blood pressure. In the long term, it can cause anxiety, dental problems and weight loss.

“You see people as young as their 30s with congestive heart failure as if they were in their 70s,” he said.

Nationwide, amphetamine-related hospitalizations were primarily due to mental health or cardiovascular complications of the drug use, the JAMA study found. About half of the amphetamine hospitalizations also involved at least one other drug.

Because there has been so much attention on opioids, “we have not been properly keeping tabs on other substance use trends as robustly as we should,” said study author Dr. Tyler Winkelman, a physician at Hennepin Healthcare in Minneapolis.

Sometimes doctors have trouble distinguishing symptoms of methamphetamine intoxication and underlying mental health conditions, said Dr. Erik Anderson, an emergency room physician at Highland Hospital in Oakland, Calif. Patients also may be homeless and using other drugs alongside the methamphetamine.

Unlike opioid addiction, meth addiction cannot be treated with medication. Rather, people addicted to the drug rely on counseling through outpatient and residential treatment centers.

The opioid epidemic, which resulted in about 49,000 overdose deaths last year, recently prompted bipartisan federal legislation to improve access to recovery, expand coverage to treatment and combat drugs coming across the border.

There hasn’t been a similar recent legislative focus on methamphetamine or other drugs. And there simply aren’t enough resources devoted to amphetamine addiction to reduce the hospitalizations and deaths, said Maxwell, a researcher at the Addiction Research Institute at the University of Texas at Austin. The number of residential treatment facilities, for example, has continued to decline, she said.

“We have really undercut treatment for methamphetamine,” Maxwell said. “Meth has been completely overshadowed by opioids.”