Why Avoid Dextromethorphan? A Guide to Its Risks and Side Effects

October 10, 2025 •

4 min read

Dextromethorphan (DXM) is a common ingredient in over 120 over-the-counter cough and cold medicines [1.2.6]. Despite its widespread availability, there are compelling reasons why to avoid dextromethorphan, from dangerous drug interactions to a significant potential for abuse and adverse side effects.

Quick Summary

This article details the significant risks tied to dextromethorphan (DXM), including its potential for abuse, severe side effects, and life-threatening interactions with other common medications like antidepressants.

Key Points

High Potential for Abuse: At high doses, DXM is used recreationally for its hallucinogenic effects, leading to addiction risk and thousands of ER visits annually [1.6.2].
Risk of Serotonin Syndrome: Combining DXM with antidepressants like MAOIs or SSRIs can cause a potentially fatal condition called serotonin syndrome [1.3.7, 1.4.1].
Dangerous in Combination Products: Many OTC products mix DXM with other drugs like acetaminophen, which can cause severe liver damage when taken in high doses [1.2.6].
Not for All Coughs: DXM suppresses the cough reflex and should not be used for chronic coughs or those with a lot of mucus, as this can be harmful [1.5.5].
Unsafe for Certain Populations: It should be avoided in children under 4 and used with caution in people with liver or chronic respiratory conditions [1.5.5, 1.5.4].
Adverse Side Effects: Even at normal doses, DXM can cause dizziness, drowsiness, and nausea; high doses can lead to respiratory depression and seizures [1.3.2, 1.5.7].
Safer Alternatives Exist: For productive coughs, the expectorant guaifenesin is often a better choice, and natural remedies like honey can also provide relief [1.7.3, 1.7.2].

What is Dextromethorphan?

Dextromethorphan (DXM) is a synthetically produced cough suppressant that is a structural analog of codeine [1.2.2]. It is found in more than 120 different over-the-counter (OTC) cold and cough preparations, making it one of the most common antitussive agents available [1.2.6]. It works by acting on the part of the brain that controls the cough reflex [1.5.7]. While effective for a dry, non-productive cough when used as directed, its widespread availability and psychoactive properties at high doses present several risks that warrant caution [1.2.2, 1.3.4].

The High Potential for Abuse and Overdose

One of the most significant reasons to be cautious with dextromethorphan is its potential for recreational misuse, often referred to as "robotripping" or "skittling" [1.2.4]. When taken in doses significantly higher than recommended, DXM acts as a dissociative hallucinogen, similar to PCP or ketamine [1.3.4, 1.3.5]. Abuse of DXM leads to about 6,000 emergency department visits annually, with half of those cases involving individuals between 12 and 25 years old [1.6.1, 1.6.2].

The effects are dose-dependent and categorized into "plateaus" [1.2.4, 1.2.5]:

First Plateau (100-200 mg): Mild stimulation, dizziness, and hyperactivity [1.2.4].
Second Plateau (200-400 mg): Euphoria, hallucinations, and impaired motor function, comparable to alcohol intoxication [1.2.4].
Third Plateau (500-1,500 mg): A trance-like state with more intense hallucinations and potential for aggressive behavior [1.2.4].
Fourth Plateau (>1500 mg): Complete dissociation and nonresponsiveness [1.2.5].

An overdose can lead to severe symptoms such as seizures, respiratory depression (slowed breathing), high blood pressure, coma, and even death [1.2.3, 1.2.4]. The risk is compounded because many OTC products containing DXM also include other active ingredients like acetaminophen or pseudoephedrine, which are toxic in large quantities and can cause liver damage or heart problems [1.2.6, 1.2.7].

Dangerous Drug Interactions: The Risk of Serotonin Syndrome

Dextromethorphan should be avoided by anyone taking certain types of antidepressants due to the risk of a life-threatening condition called serotonin syndrome [1.3.7]. This occurs when there is an excessive amount of serotonin in the brain [1.3.5].

Key interactions to be aware of:

MAOIs (Monoamine Oxidase Inhibitors): Taking DXM with an MAOI (e.g., phenelzine, isocarboxazid) or within 14 days of using one is contraindicated [1.5.7]. This combination can cause serious, life-threatening side effects [1.5.7].
SSRIs and SNRIs: Combining DXM with Selective Serotonin Reuptake Inhibitors (e.g., fluoxetine, sertraline) or Serotonin-Norepinephrine Reuptake Inhibitors (e.g., duloxetine, venlafaxine) also significantly increases the risk of serotonin syndrome [1.2.2, 1.4.1].

Symptoms of serotonin syndrome can range from mild to severe and include agitation, confusion, rapid heart rate, high blood pressure, dilated pupils, muscle rigidity, heavy sweating, and fever [1.3.5, 1.4.5]. In severe cases, it can lead to seizures, rhabdomyolysis (muscle breakdown), and death [1.4.5].

Common and Severe Side Effects

Even at therapeutic doses, dextromethorphan can cause a range of unwanted side effects. Common adverse effects are generally mild but can include [1.3.2, 1.3.3]:

Dizziness and lightheadedness
Drowsiness
Nausea and vomiting
Stomach pain
Nervousness or restlessness

More severe side effects, although rarer at correct dosages, can occur and warrant immediate medical attention. These include severe dizziness, confusion, hallucinations, seizures, and slow, shallow breathing [1.5.7].

Special Populations Who Should Avoid Dextromethorphan

Certain groups should exercise extreme caution or avoid DXM altogether:

Children Under 4: The FDA advises against the use of OTC cough and cold medicines in children younger than 4 years old due to the risk of serious side effects [1.5.5, 1.5.7].
Patients with Respiratory Conditions: Individuals with chronic coughs related to smoking, asthma, or emphysema, or coughs that produce a lot of mucus, should not use DXM without consulting a doctor [1.5.4, 1.5.5]. Suppressing a productive cough can be harmful.
Individuals with Liver Impairment: DXM is metabolized by the liver, and while no specific dose adjustments are provided, those with severe liver disease may have higher blood levels of the drug, increasing the risk of side effects [1.2.2, 1.3.1].
Pregnant or Breastfeeding Women: While standard doses are generally considered acceptable, it is recommended to avoid alcohol-containing DXM products during pregnancy [1.2.2]. It is not fully known if DXM is harmful to an unborn baby, so consultation with a doctor is crucial [1.5.7]. A very low amount is excreted in breast milk [1.2.2].

Alternatives to Dextromethorphan


Medication/Remedy	Mechanism of Action	Primary Use	Key Reason to Choose over DXM
Guaifenesin	Expectorant; thins and loosens mucus in the airways [1.7.5].	Productive, "wet" coughs with chest congestion [1.7.3].	Does not suppress the body's natural reflex to clear mucus; has fewer drug interactions [1.7.3].
Benzonatate	Non-narcotic cough suppressant; numbs the stretch receptors in the lungs and airways.	Symptomatic relief of cough.	A prescription alternative that does not have the same abuse potential or risk of serotonin syndrome [1.7.4].
Honey	Soothes the throat and has been shown to be effective for cough symptoms [1.7.2].	Soothing a dry, irritated throat, especially at bedtime [1.7.2].	A natural remedy with minimal side effects (not for children under 1 year old) [1.7.2].
Hydration & Humidifier	Thinning mucus and lubricating the throat [1.7.2, 1.7.5].	General cough and cold symptoms.	A non-pharmacological approach that supports the body's own clearing mechanisms without side effects [1.7.5].

Conclusion

While dextromethorphan is an effective and readily available cough suppressant, the reasons to avoid it are significant. The high potential for abuse, the life-threatening risk of serotonin syndrome when combined with common antidepressants, and a range of side effects make it a medication that requires careful consideration. For many individuals, particularly those on other medications or with underlying health conditions, safer alternatives like guaifenesin for productive coughs or simple home remedies may be a better choice. Always read labels carefully and consult with a healthcare professional or pharmacist to ensure a medication is safe for you.

For more authoritative information, you can visit the National Institutes of Health's page on Dextromethorphan.

Frequently Asked Questions

The most serious risks are serotonin syndrome, which can be fatal when DXM is mixed with antidepressants like MAOIs or SSRIs, and overdose from abuse, which can cause seizures, respiratory depression, and coma [1.3.7, 1.5.7].

No, you should not take dextromethorphan with antidepressants like MAOIs, SSRIs, or SNRIs. The combination can lead to a dangerous and potentially life-threatening condition called serotonin syndrome [1.4.1, 1.2.2].

Signs of a dextromethorphan overdose include nausea, vomiting, drowsiness, blurred vision, fast heartbeat, hallucinations, seizures, unsteadiness, and slow or shallow breathing [1.3.2, 1.2.3].

Standard doses are generally considered acceptable, but it's classified as a pregnancy category C drug, and its effects on an unborn baby are not fully known. It is recommended to avoid products containing alcohol and consult a doctor before use [1.2.2, 1.5.7].

Dextromethorphan is a cough suppressant. For a cough with phlegm (a productive cough), suppressing the cough can prevent your body from clearing mucus from your airways. An expectorant like guaifenesin is a better choice to help thin the mucus [1.5.5, 1.7.5].

Dextromethorphan itself is metabolized by the liver [1.2.2]. The greater danger comes from combination products where DXM is mixed with acetaminophen, as high doses of acetaminophen can cause severe liver damage [1.2.6].

Guaifenesin is a safer alternative for a productive, wet cough. It is an expectorant that works by thinning and loosening mucus, making your coughs more effective at clearing your airways [1.7.3, 1.7.5].