Drug poisoning now exceeds car accidents as the No. 1 cause of unintentional death in Arizona.

One of the biggest contributing drugs does not require a prescription: acetaminophen. The active ingredient in Tylenol is associated with 30 percent of the poisoning fatalities in the U.S. and is found in more than 600 over-the-counter and prescription medications. Therein lies the problem, experts say.

“If a person has a cold, they’ll go to the drugstore and get a cold medication to treat their symptoms. But sometimes they need two kinds to treat their symptoms, and they also have a headache” said Dr. Keith Boesen, director of the Arizona Poison and Drug Information Center, which is trying to educate local residents that dosage matters.

“They’ve now taken three medications, not realizing that they all contain some of the same medications.”

Chronic pain sufferers, in addition to their prescribed medication for pain, will often use over-the-counter pain medications, such as Aleve or Tylenol.

Whether or not people are taking prescribed pain medications, over-the-counter drugs can still pose a serious threat to their health if they’re unclear about the ingredients.

The maximum recommended adult dose of acetaminophen is 4,000 milligrams per day. One Tylenol Extra Strength pill contains 500 mg, making eight pills a day the maximum safe dose if no other acetaminophen-containing medications are used.

According to a 2012 report by the Pima County Forensic Science Center, 32 percent of unintentional deaths were caused by overdoses. Car accidents accounted for 27 percent.

For decades, car wrecks had been the leading cause of unintentional deaths in Arizona and the United States. A 2012 injury and mortality report by the Arizona Department of Health Services noted that in 2009 drug poisonings surpassed car accidents in unintentional deaths.

In 2011, there were 277 drug-overdose deaths in Pima County. That number increased 13 percent in 2012, with 314 deaths.

“One of the drivers of this statistic is the increase in prescription pain medications,” Boesen said. “That (increase), combined with advances in vehicular safety, has opened the door for prescription medication abuse to become a significant problem in the United States.”

Nine out of 10 poisonings were drug-related, and nearly 80 percent of the drug overdoses in the United States were unintentional.

Prescription pain medications, when used in excess or in combination with other drugs, can be very dangerous, sometimes leading to liver failure or death, Boesen said.

“Many of these situations are a result of drug interactions, including over-the-counter medications,” Boesen said.

A November 2011 study by the U.S. Centers for Disease Control and Prevention showed that the number of deaths caused by prescription drugs exceeded the number of deaths from cocaine and heroin combined.

“There was a concerted effort in the 1990s and early 2000s in the recognition of pain and chronic pain as a disease entity,” said Dr. Mazda Shirazi, medical director for the Arizona Drug and Poison Center and an emergency room physician.

The recognition, he said, led to an increase in prescriptions of narcotics and opiumlike medications, such as oxycodone.

“Dosage matters. Patients don’t realize how important it is,” Shirazi said. “Many people think if one is good, two is better, and that’s not the case.”

It’s important for patients to talk to their physician or pharmacist about their medications: what’s in them, what their dosage is, and what they can interact with.

Shirazi encourages everyone to call the poison center with any questions about any medications, prescription or over-the-counter.

Manned by nationally certified, expertly trained pharmacists, the poison center is prepared to go through a medication’s ingredients with patients, providing detailed explanations. The poison center is open 24 hours a day, seven days a week.

“Don’t use the Internet to look up medication,” Shirazi said. “What’s available to the general public is street-drug-type information, and there’s little verification of sources and accuracy.”

It’s also important to recognize that special populations, such as small children, older adults or chronic pain sufferers, are at an increased risk for toxicity. In small children, small doses can be fatal.

“Keep medications together for each person,” said Liz Barta, poison education specialist for the center. “Make sure to label the containers to avoid mix-ups.”

Caitlin Schmidt is a journalism student at the University of Arizona and an apprentice at the Star. Email her at starapprentice@azstarnet.com.