Man told 911 he thought he killed wife after taking too much cold medicine

Matthew Phelps is charged with one count of murder for allegedly fatally stabbing his wife, Lauren Phelps.
6:10 | 09/06/17

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Transcript for Man told 911 he thought he killed wife after taking too much cold medicine
They looked like the picture of marital bliss. Lauren and Matt Phelps, newlyweds, married for barely ten months. Lauren, 29, a Sunday school teacher and auditor who ran an online business on the side. So thank you guys so much for watching, and I will talk to you guys later. Bye. Reporter: Matt, 28, worked at a lawn service in North Carolina and once attended a bible college. But that image of what seemed from the outside like the perfect all-American couple shattered as caught in a dramatic call to 911. Where is the knife right now? Reporter: Matt Phelps now stands accused of murdering his wife. He hasn't yet entered a plea, and what we don't know is whether or not cold medication he took will play a role in this case. Sir, you could receive the death penalty or life without the possibility of parole. Reporter: Just after 1:00 A.M. On Friday a man called authorities with this startling revelation. I had a dream, and then I turned on the lights and she's dead on the floor. How? How? I have blood all over me, and there's a bloody knife on the bed. And I think I did it. Reporter: The Raleigh police department says it has altered the recording to disguise the caller's voice. The man said he took over-the-counter medication to help him sleep just hours before. I took more medicine than I should have. What medicine did you take? I took -- I took coricidin cough and cold because I know it can make you feel good. So a lot of times I can't sleep at night. Is she breathing at all? Is her chest moving? Is anything going on with her? No. Okay. We're going to -- The blood is dried on me. It's dried? The blood is not wet on me. The blood is dry. When officers arrived at the Phelps home in Raleigh, they found Lauren with stab wounds. They rushed her to the hospital, where she was pronounced dead. Lauren's heartbroken family said in a statement, "She was all about her family. Her four nephews were her whole world and church was a priority for her." Matt Phelps' defense attorney is asking the public to wait for more information before judging his client. Be patient with everybody so that we can all together get to the bottom of this really significant tragedy. Reporter: Bayer, the manufacturer of coricidin, defended its product in a statement, saying "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." What Phelps said in that 911 call already raising questions. Listen, this ain't the cold and flu season. Okay? So there's no evidence he had the cold or a flu. He also said he takes coricidin because it makes him feel good and helps him go to sleep. He said nothing about being ill. If there was literature, proof, evidence that this particular cough syrup has led to violent episodes in the past, could there be a defense? Maybe. Particularly if there was no warning. But there is no evidence that we know of. Ambien's a different story. Reporter: One of the best-known cases of what's become known as the ambien defense is that of Carrie Kennedy. I have no memory. Until I was stopped at a traffic light. Reporter: In 2012 Kennedy, the daughter of Robert Kennedy, sideswiped a tractor-trailer and allegedly left the scene. Police found her slumped over the wheel of her car. She faced a single misdemeanor count of driving while impaired. Her defense argued that she unnothingly took a generic form of ambien, mistaking it for her thyroid drug, and one of the expert witnesses in the trial, Dr. David Benjamin, said the medication can cause an automatic type of behavior or zombieism and that people might become impaired but not know it. Had she had her faculties about her she would have pulled over and called aa. Reporter: Sanofi, the maker of ambien, said in a statement that it stands behind the robust clinical data that have demonstrated the safety and efficacy of ambien since its approval in the U.S. In 1992. Kennedy was found not guilty. But in another case, one not involving a traditional pharmaceutical, the outcome was tragically different. Report of a domestic violence in port. Reporter: In April 2014 Christine Kirk called 911 saying her husband had taken some marijuana and was talking like it was the end of the world and wanted her to shoot him. Telling the 911 operator that he was totally hallucinating. He grabbed the gun and she's screaming. The line disconnected. Reporter: Richard Kirk was charged with first-degree murder of his wife and he pled not guilty by reason of insanity. Researchers suggesting the pot-laced candy which is legal in Colorado may have contributed to his psychotic break. The guardians of Kirk's children filed a wrongful death suit against the maker and distributor of the chewy candy alleging they negligently, recklessly and purposefully concealed vital dosage and labeling information claiming the package doesn't warn buyers that the high in edibles could lead to paranoia, psychosis and hallucinatio hallucinations. We don't have a lot of literature on what the side effects would be on a person who has ingested recreational marijuana. So a manufacturer could potentially be held liable for that. An attorney for the makers of the candy told ABC that they were complying with all state labeling requirements at the time that said marijuana could have adverse health effects and called the suit's claims preposterous and baseless. Kirk later changed his plea, agreeing to serve 25 to 30 years in prison for second-degree murder. As for Matt Phelps, he will be back in court later this month. Until more answers are uncovered -- Hi, everybody. It's Lauren. Reporter: -- Lauren's family is left waiting and wondering what went so wrong.

This transcript has been automatically generated and may not be 100% accurate.

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