Dextromethorphan is an ingredient in many over-the-counter cough medicines. When used as directed, it may help reduce coughing for some people. Over-the-counter does not always mean risk-free. Adverse effects of dextromethorphan can become serious if someone takes too much, mixes it with certain medicines or uses it to feel high. If cough medicine use is connected to anxiety, confusion, hallucinations, mood changes or safety concerns, mental health support may help you understand what kind of care may fit.
This article is educational. It does not replace medical care. If you think someone may have taken too much dextromethorphan, call Poison Control at 800-222-1222 or seek emergency care.
What is dextromethorphan?
Dextromethorphan is a cough suppressant. It is often listed as “DM” on cough and cold medicine labels. Some products contain only dextromethorphan. Others combine it with medicines such as antihistamines, decongestants, pain relievers or expectorants.
People should follow package or prescription directions and not take more than directed. A label check matters because combination products can add extra risks. For example, some cold medicines contain acetaminophen, which can harm the liver when too much is taken.
What are common side effects?
Some adverse effects of dextromethorphan may be mild. Others may need quick medical attention.
Common side effects can include:
- Drowsiness — Feeling sleepy or slowed down
- Dizziness — Feeling lightheaded or unsteady
- Nausea — Feeling sick to your stomach
- Vomiting — Throwing up after taking the medicine
- Restlessness — Feeling agitated or unable to settle
Adverse effects from cough suppressants are rare, but nausea, stomach discomfort, drowsiness and dizziness are among the more common reactions.
What symptoms may mean overdose or poisoning?
Dextromethorphan overdose can be dangerous. Symptoms may affect the body, thoughts, mood and behavior.
Possible overdose signs may include:
- Fast heartbeat — Heart racing or pounding
- Trouble breathing — Slow, shallow or difficult breathing
- Confusion — Not knowing what is happening
- Hallucinations — Seeing or hearing things that are not there
- Seizures — Uncontrolled shaking or loss of awareness
- Coma — Being unable to wake up
Call 911 right away if a person has collapsed, had a seizure, has trouble breathing or cannot be awakened.
Poison Control is also available 24/7 at 800-222-1222. You can call even if you are not sure whether the situation is an emergency.
Can dextromethorphan affect mental health?
Yes, especially when someone takes too much or misuses it. High amounts of dextromethorphan can affect the brain in ways that may feel scary or hard to control.
Poison Control notes that high doses can lead to panic, extreme agitation, hallucinations, psychosis, seizures, coma or death.
Mental health symptoms may include:
- Panic — Sudden intense fear or dread
- Paranoia — Feeling watched, threatened or unsafe
- Hallucinations — Hearing or seeing things others do not
- Dissociation — Feeling detached from your body or surroundings
- Mood changes — Feeling very sad, irritable or emotionally out of control
These symptoms do not prove a mental health diagnosis. They do mean the person may need medical or clinical support.
Lightfully treats adults with anxiety disorders, mood disorders, trauma-related disorders, thought-related symptoms and other mental health concerns.
What drug interactions should I know about?
Dextromethorphan can interact with some medicines and substances. This can raise the risk of serious side effects.
One concern is serotonin syndrome. This is a dangerous reaction that can happen when there is too much serotonin activity in the body. Poison Control lists dextromethorphan as one of the medicines that can affect serotonin activity.
Alcohol and other substances may also increase other side effects, such as drowsiness or impairment. It is safest to ask a doctor or pharmacist before combining medicines.
Why can misuse be risky?
Some people take dextromethorphan to feel high or disconnected. This can be risky because the amount in the body can become unsafe. It can also be hard to know what other ingredients are in the product.
The FDA warns parents and caregivers to use caution with cough and cold medicines and notes reports of serious harm in children.
For adults, misuse may also connect with anxiety, depression, trauma symptoms, sleep problems or feeling unable to cope. A mental health evaluation can help sort through what is happening.
When should someone seek help?
Seek medical help right away for trouble breathing, seizures, chest pain, severe confusion, loss of consciousness or suspected overdose. Call 911 if the person cannot stay awake or may be in danger.
It may also be time to seek mental health support if dextromethorphan use is linked to:
- Repeated misuse — Using more than directed or using it to cope
- Mood changes — Depression, irritability or emotional crashes
- Anxiety symptoms — Panic, fear or restlessness
- Thought changes — Paranoia, hallucinations or confusion
- Safety concerns — Self-harm urges or suicidal thoughts
A clear list of symptoms can make the first call with a provider easier.
If you may not be able to stay safe, call or text 988, call 911 or go to the nearest emergency room.
How can Lightfully support the next steps?
Dextromethorphan side effects can raise medical, emotional and safety concerns. If symptoms continue after the immediate medical issue is handled, mental health care may help.
At Lightfully Behavioral Health, licensed clinical experts provide whole-person-centered care for adults experiencing anxiety, depression, trauma-related symptoms, thought-related symptoms, self-harm behaviors, suicidal thoughts and other mental health concerns. Care may include therapy, psychiatry, group support and a personalized treatment plan.
Lightfully offers Residential Treatment, Partial Hospitalization Program, Intensive Outpatient Program and Virtual Services.
Daily habits that support mental health may also help create steadier routines while seeking care.
Change is possible. When you’re ready to take the first step, reach out to our Admissions Concierge Team. We’ll take the next steps together, toward the fullest, brightest version of you.
Frequently asked questions
Is dextromethorphan safe?
Dextromethorphan may be safe for some people when used exactly as directed. It can become unsafe if someone takes too much, mixes it with certain medicines or uses it to feel high.
What are the most common adverse effects of dextromethorphan?
Common side effects may include drowsiness, dizziness, nausea, vomiting and stomach discomfort. More serious symptoms can include hallucinations, trouble breathing, seizures or severe confusion.
Can dextromethorphan cause hallucinations?
Yes, hallucinations can happen, especially with high doses or misuse. Hallucinations after taking cough medicine should be taken seriously and may need medical attention.
What should I do if someone took too much dextromethorphan?
Call Poison Control at 800-222-1222 or seek emergency care. Call 911 right away if the person has trouble breathing, has a seizure, cannot wake up or may not be safe.
Can dextromethorphan interact with antidepressants?
Yes. Dextromethorphan can interact with some antidepressants and other medicines that affect serotonin. Ask a doctor or pharmacist before combining medications.
When should I seek help for suicidal thoughts?
Seek help right away if you are thinking about suicide, making a plan or worried you may not be able to stay safe. If this is an emergency, call or text 988 or go to the nearest emergency room.
When should I seek treatment for self-harm behaviors?
You may benefit from treatment if you are hurting yourself, thinking about hurting yourself or relying on self-harm to cope with distress. If you may not be able to stay safe or suicidal thoughts are present, call or text 988 or seek emergency care.
Who is Lightfully’s Partial Hospitalization Program for?
Our Partial Hospitalization Program is for adults who need structured daytime care without staying overnight. Our Admissions Concierge and clinical teams can help determine whether this level of care fits your current needs.
Who is Lightfully’s Intensive Outpatient Program for?
Our Intensive Outpatient Program is for adults who need more support than weekly therapy while continuing daily life at home. Our Admissions Concierge and clinical teams can help determine whether this level of care fits your current needs.
Who is Lightfully’s Residential Treatment Program for?
Our Residential Treatment Program is for adults who need 24-hour support in a home-based setting while they focus on mental health treatment. Our Admissions Concierge and clinical teams can help determine whether this level of care fits your current needs.
