Sept. 8, 2017 -- The 911 call is chilling.

“I think I killed my … I took more medicine than I should.”

That’s the start of more than 6 minutes of audio of a 911 call made by Matthew James Phelps after he woke up and said he found his wife stabbed to death

“I had a dream. And then I turned on the lights and she is dead on the floor,” he says in the call. “I have blood all over me, and there is a bloody knife on the bed, and I think I did it.”

Phelps tells the operator he took Coricidin HBP Cough and Cold to help him sleep. “I know it can make you feel good, and sometimes I can’t sleep at night,” he says.

He later breaks down sobbing on the phone with the dispatcher. “Oh God. She didn’t deserve this. Why?”

The News & Observer newspaper in Raleigh, NC, reports that Phelps’ attorney says the effects of the cold medicine he took are “certainly an interesting subject of inquiry” as the case moves forward.

Phelps, 29, was charged with murdering his wife of less than a year -- Lauren Ashley-Nicole Phelps, also 29. Prosecutors say he could face the death penalty or life in prison if convicted. He did not have a criminal record, according to the News & Observer.

But can common cold medication really make someone commit a violent and deadly crime?

Side Effects and Abuse

The two main active ingredients in Coricidin are the antihistamine chlorpheniramine, which makes it easier to breathe, and dextromethorphan (DXM), a cough suppressant. The FDA approved DXM, found in more than 100 over-the-counter (OTC) cold and cough medicines, in the 1950s.

Bayer, which makes Coricidin HBP Cough and Cold, issued this statement about the case:

“Bayer extends our deepest sympathies to this family. Patient safety is our top priority, and we continually monitor adverse events regarding all of our products. There is no evidence to suggest that Coricidin is associated with violent behavior.”

Stefanie Ferreri, PharmD, a clinical professor at the University of North Carolina Eshelman School of Pharmacy in Chapel Hill, says DXM is considered safe and effective when taken at recommended doses. But, she adds, even at that amount, patients will often be warned of possible side effects.

“We usually recommend to be careful if you drive because we know it will affect your brain even at the recommended doses,” Ferreri says.

One tablet of Coricidin HBP Cough and Cold contains 30 mg of DXM. The recommended daily dosage is no more than four tablets, or 120 mg of DXM.

Ferreri says the medicine slows down breathing and suppresses the cough reflex in the brain, which can make people feel drowsy or dizzy at regular doses and euphoric or high if they abuse or misuse it.

And the drug is often abused, particularly by teens, and that can trigger psychotic behavior in rare cases, Ferreri says.

The medicine is sold under street names like poor man’s PCP, Red Devils, and Skittles., a prevention campaign run by the Consumer Healthcare Products Association, says 1 in 30 teens report abusing DXM. When taken at high doses, DXM can cause hallucinations, mild distortions of color and sound, as well as loss of motor control, according to the association, which represents OTC drug manufacturers and distributors.

“When people abuse it and take eight to 20 times more than is recommended, that is when we start to see psychosis and hallucinations and euphoria and feelings of getting high,” Ferreri explains.

Officials have not released details about how much Coricidin Phelps had taken.

There is not a lot of research on the subject. But a 2008 study found Coricidin HBP can cause psychosis when misused and warns those who treat teens to be aware of this.

And a 2013 study reports on a 40-year-old man hospitalized for acute psychosis after he was found acting bizarrely at a supermarket. After rapidly taking 30 tablets of Coricidin HBP, he showed paranoid behavior and said he could “look at people and know exactly what they were thinking.”

Study author Siva Kumar Aytha, MBBS (the equivalent of an MD in India), observed the case while at the University of Nebraska Medical Center. He is now a resident doctor in emergency medicine at Fortis Hospital in Kolkata, India.

“This man in particular was paranoid. He was restless. He had psychosis. He was not aware of what he was doing as he tried to push off his IV and throw things,” he says.

But 2 days after the man stopped taking Coricidin under hospital supervision, Aytha reported that his mental state was stable with no evidence of psychosis. He didn’t need antipsychotic treatment and didn’t remember much of the episode.

When he went searching for other similar cases, Aytha says there was little to be found.

“Dextromethorphan does have the potential to cause psychosis, but there are very limited cases showing this,” he says, adding that he was surprised to see the reaction mimic one to PCP. “No one would expect the dextromethorphan would be such a potent psychotic, because this is such a commonly used medication.”

He stresses that what he published is a single case report. He says this topic needs more studies to reach any sort of conclusions.

What You Need to Know

In general, if you follow the recommended dosing of OTC cough and cold medications, Ferreri and others say, you will likely be fine. But she warns that OTC cold medicines can interact with other medications and don’t mix well with alcohol. Also, the drugs may last from 3 to 30 hours in your system, depending on how fast you metabolize them, Aytha says.  

Ferreri recommends reading labels carefully and searching for the active ingredient so you know if you are taking DXM. She suggests parents also learn about teen abuse by visiting websites like

“Over-the-counter medications need to be taken seriously. They do have side effects and drug interactions. So make sure to speak with your doctor or pharmacist before taking something you haven’t taken before so you know what to expect,” Ferreri suggests.


Show Sources

Bayer U.S.

Consumer Healthcare Products Association. “Dextromethorphan: Preventing Teen Cough Medicine Abuse.”

Siva Kumar Aytha, MBBS, Kolkata, India.

Stefanie Ferreri, PharmD, UNC Eshelman School of Pharmacy, Chapel Hill, NC.

City of Raleigh, NC, Police Department. “What is DXM,” “What does abuse look like?”

D.L. Dickerson, The Journal of Addictive Diseases. 2008.

SK Aytha, The Primary Care Companion for CNS Disorders, Nov. 21, 2013.

S. Banerji, American Journal of Health System Pharmacy, Oct. 1, 2001.

The News & Observer: “Murder suspect says he took too much cold medicine, then woke to find his wife dead,” Sept. 1, 2017; “Lawyer says effects of cold medicine will be ‘subject of inquiry’ in man’s murder trial,” Sept. 5, 2017.

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