Overdosing on Cold and Flu Medications

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Over-the-counter (OTC) cough and cold medicines are widely available, low-cost, and can help relieve some symptoms of upper respiratory infections and the flu. While they have some benefits, these medications carry a risk of overdosing.

Overdosing of OTC cold and flu remedies is often accidental—due to errors like misreading product labels or dosing. Sometimes, these medications are also intentionally abused. Signs of overdose include excessive fatigue or dizziness, sudden jitteriness, confusion, and more.

This article discusses intentional and accidental overdoses of cold and flu medicines, as well as signs of overdose and medication abuse.

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How an Accidental Overdose Happens

Overconsumption of drugs found in cold and flu remedies poses health risks. These drugs include:

  • Acetaminophen: relieves pain and lowers fever by stopping the production of certain chemicals in the brain that cause pain and fever
  • Non-steroidal anti-inflammatories (NSAIDs): relieve pain and reduce fever and inflammation
  • Dextromethorphan: a cough suppressant that works in the part of your brain that makes you cough, telling your body to cough less
  • Pseudoephedrine: relieves nasal congestion by reducing swelling in the sinuses to help mucus and air flow more freely
  • Antihistamines: block a chemical called histamine that causes symptoms such as sneezingitchy eyes, and postnasal drip

Using these medications with alcohol can also lead to overdosing.

There are several reasons that accidental overdoses can happen with cold and flu medications, including:

  • Ignoring dosing recommendations and taking whatever dose is desired
  • Taking more frequent doses to try to overcome an illness faster
  • Misreading a product label
  • Measuring the dose incorrectly

Taking different OTC cold and flu remedies can cause an overdose if they contain some of the same ingredients. For example, if you were to take a multi-symptom medication like NyQuil along with Tylenol (or Tylenol Extra Strength) for fever and pain, you could overdose on acetaminophen, which is in both products.

Taking too much acetaminophen can potentially cause liver damage. This risk is even higher with alcohol. According to research published in the Journal of Clinical and Translational Hepatology, acetaminophen overdose accounts for more than 50% of overdose-related acute liver failures in the United States.

Preventing Overdose

Ways to avoid these mistakes include:

  • Reading the product labels
  • Avoiding co-administration of remedies with the same ingredients
  • Limiting yourself to the recommended dose
  • Abstaining from alcohol when taking cold and flu medications

Can You Overdose on Nyquil?

Nyquil Cold and Flu is a combination medication containing acetaminophen, dextromethorphan, and doxylamine. Overdose side effects can include drowsiness, blurred vision, upset stomach, nervousness, or more serious side effects such as confusion, hallucinations, trouble urinating, and irregular heartbeat.

Do not take more than four doses in 24 hours. See the directions on the box for the correct dosage for adults and children.

Nyquil should not be used as a sleep aid. A 2015 review concluded there weren’t enough quality studies to determine its safety or effectiveness as a sleep aid.

Signs of Accidental Overdose

Though you may never anticipate a cold and flu medication overdose, they can easily happen. It's important to recognize the signs of an OTC cold and flu medication including:

  • Excessive tiredness or lethargy
  • Extreme dizziness or drowsiness
  • Sudden anxiety or jitteriness
  • Confusion
  • Abdominal pain
  • Labored or shallow breathing
  • Loss of appetite
  • Nausea or vomiting
  • Rapid heart rate
  • Blurred vision
  • Dilated pupils
  • Dark-colored urine
  • Unresponsivenessness

In cases of overdose, get emergency medical help or call Poison Control at 1-800-222-1222. It's important to get immediate medical care, even if you don't notice any symptoms yet.

Abuse of Cold/Flu Medication

Several different ingredients in cold, cough, and flu medications can be abused.

Dextromethorphan (DMX)

Some people abuse OTC cold, cough, and flu remedies containing dextromethorphan (DMX). These products are readily available throughout the United States in syrup, tablet, and powder form. Brands of cough medications containing DMX include:

  • Delsym 12-hour Cough
  • Robitussin Cough Long-Acting
  • Triaminic Long-Acting Cough
  • Vicks DayQuil Cough

There are over 50 brands of combination products (such as cough and cold, or flu) medications for both adults and children that contain DMX. Some examples include:

  • Alka-Seltzer Plus Cold and Cough Formula
  • Children's Dimetapp Multisymptom Cold and Flu
  • Children's Mucinex Cough
  • Children's Robitussin Cough and Cold CF
  • Coricidin HBP Day and Night Multi-Symptom Cold
  • Diabetic Tussin DM
  • PediaCare Children's Fever Reducer Plus Cough and Runny Nose
  • Sudafed PE Day/Night Cold
  • Theraflu Cold and Cough
  • Triaminic Cough and Sore Throat
  • Tylenol Cold and Cough Daytime
  • Vicks Children's NyQuil Cold and Cough

The abuse of DMX is most common among 8th to 12th graders. When swallowed or snorted in excess, DMX can cause hallucinogenic effects similar to the anesthetic drug ketamine or the street drug phencyclidine (also known as PCP or "angel dust.") Depending on how much is taken, the effects can last for as long as six hours or even more.

The overuse of DMX is associated with an array of side effects, including:

  • A feeling of floating
  • Confusion and disorientation
  • Impaired judgment
  • Blurred vision
  • Loss of coordination
  • Slurred speech
  • Dizziness
  • Excessive sweating
  • Hyperactivity
  • Hallucinations
  • Rapid or pounding heartbeats
  • A drop in body temperature
  • Hot flashes
  • Diarrhea
  • Abdominal pain
  • Nausea and vomiting
  • Unconsciousness

Repeated abuse of DXM at high doses can also cause a condition known as chemical psychosis in which a person loses touch with reality. Referred to by some as "poor man's psychosis," the DMX-induced disorder (characterized by paranoia, delusions, hallucinations, and disassociation) has been known to lead to impulsive and even violent acts, including assault and self-harm.

An overdose of DMX can lead to more serious symptoms, including seizures, cerebral hemorrhage (bleeding in the brain), permanent brain damage, and even death.

To prevent abuse in your family, educate your kids about the dangers of DMX, monitor their activities, keep track of all cold and flu medications in the home, and avoid stockpiling medications containing DMX.

Alcohol

Alcohol used to be a common ingredient in many OTC cough syrups. As a public safety measure, alcohol is no longer a component of most OTC remedies. However, some cold and flu combination medications such as NyQuil and Theraflu still contain alcohol.

Because fewer remedies contain alcohol, there is less of a concern for abuse.

Codeine

Codeine has also been an ingredient in many OTC cough syrups that were abused.

As a public health safety measure, codeine has been classified as a controlled substance. Products containing 90 mg or more of codeine, like Tylenol 3, are Schedule III controlled substances and require a prescription to use them.

Signs of Abuse

Since DMX abuse is largely hidden, it is important to recognize the signs of overdose.

If you suspect that someone has overdosed on DMX, call 911 if there are any of the following symptoms:

  • Extreme disorientation or drowsiness
  • Blueish lips, fingernails, or skin
  • Vomiting
  • Seizures
  • Very slow or very rapid heartbeats
  • Slow, shallow, or labored breathing
  • Unconsciousness
  • No breathing

Until help arrives, call Poison Control 1-800-222-1222 for instructions on what to do.

Summary

While OTC cold, cough, and flu medicines have some benefits, they also carry a risk of overdosing, which can be accidental or intentional. If you're self-treating a cold, carefully read and follow product instructions and only treat the symptoms you have.

Know the signs of medication overdose and abuse to be able to get someone help if needed.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Kristina Herndon, RN
Kristina Herndon, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.