Dextromethorphan Mechanism Of Action: How Does DXM Work?

Last Updated: March 16, 2020

Dextromethorphan or DXM is a popular over-the-counter cough medication. It effectively relieves cough symptoms by affecting the part of the brain that causes cough reflexes. This article answers the questions on what dextromethorphan does and what the mechanism of action of the cough suppressant dextromethorphan is. The article also discusses DXM uses, its storage methods, the essential precautions when taking DXM, and its effective use in treating drug withdrawal symptoms.

MOA: How Does DXM Work In The Body?

DXM is an antitussive medication. As for dextromethorphan MOA, it has several mechanisms of actions that allow it to provide varied uses. Dextromethorphan is derived from morphine; therefore, it contains addictive properties that can be harmful with prolonged usage. It is a known Non-Selective Serotonin Reuptake Inhibitor, increasing the concentrations of serotonin in one’s system which induces an intense feeling of euphoria for the user known as the dextromethorphan high.

Dextromethorphan is also a sigma-1 receptor agonist with the possibility of inducing certain hallucinogenic effects depending on the dosage and the frequency of use. This property is often involved in substance-abuse disorders.

How does dextromethorphan work? The answer to this question is complex, as it disrupts the communication between one’s nerves and the brain, blocking the signals for the reaction of coughing. DXM onset of action (the duration of time it takes to experience the expected effects after administering this medication) is usually from 15 to 30 minutes. It peaks at 2.5 hours, and the results can last up to 3-6 hours.

Dextromethorphan Medical Uses

Speaking of DXM uses, it is primarily medically prescribed as a cough suppressant. Other medical uses of this drug include being a part of the treatment plans for certain neuropsychiatric disorders. Dextromethorphan does not cure a cough or speed up the healing process, but merely gives temporary relief to the user. It can be used to treat minor throat infections that cause coughs without phlegm such as the flu and the common cold. DXM is not prescribed for long term infections and problems of the air passages.

cough and illness

How Does DXM Suppress Cough

What does DXM do when taken as a cough suppressant? It is important to understand the anatomical process behind the formation of a cough reaction before answer this question. While it may feel that a cough starts in and around the chest or throat area, it is the central nervous system that generates that reaction. When the nerve endings detect an irritation, constriction, or a harmful/alien substance in the lungs or the airways, it signals part in the brain that causes a cough reflex. Dextromethorphan stops this reflex by affecting the part of the brain that causes this reflex and blocking the signal. For as long as one keeps the DXM supplied to the brain, they can have temporary relief from coughing.

Using Dextromethorphan For Children

Dextromethorphan can be prescribed to children over the age of 4 for the treatment of acute and chronic coughing. The answer to how to take DXM is extremely critical when it comes to children since the mistakes in dosage can be quite damaging.

Using DXM For Other Treatment Purposes

Clinical trials for using DXM for opiate withdrawal were conducted in 2013. It is currently prescribed in combination with Clonidine to reduce the severity of drug withdrawal symptoms, including using DXM for Kratom withdrawal. Dextromethorphan is also known to have Ketamine-like DXM antidepressant effects. Dextromethorphan for depression treatments is normally combined with other stronger enzyme inhibitors as DXM potentiates their effectiveness. Dextromethorphan for pain is also a common off-label use of the drug since DXM has the ability to impact the parts of the central nervous system associated with chronic pain. Ketamine has stronger and faster responses when compared to the pain-relieving properties of Ketamine vs. DXM.

Storage Of DXM

DXM should be kept in its tightly closed original container. It also should be kept in room temperature, away from excess heat and moisture. Most importantly, it should be kept away from the sight and reach of children. Keep both the safety caps of the container and the location it is placed properly locked at all times.

treating cough in children


Following are the known dextromethorphan contraindications:

  • Physician prescribed doses of DXM do not impair one’s ability to drive. However, recreational or excessive use of this drug may lead to weakening cognitive functions that can perturb driving behavior.
  • Before buying it over the counter, it is always better to tell the pharmacist any allergies or ongoing medications to avoid complications.
  • DXM for sale is easy available in pharmacies, so be sure to control access to this substance in children.
  • High doses of DXM can even be fatal, especially for young children. While there are no special dextromethorphan nursing implications, taking the correct dosage of this medication is very important.
  • Excessive intake of DXM can cause dextromethorphan overdose symptoms such as seizures, high blood pressure, and breathing difficulties.
  • It is recommended to not to perform dextromethorphan extraction for recreational use, which carries risks of both side effects from the substance, and complications during its extraction.
  • Do not combine medications for high blood pressure and dextromethorphan.
  • Do not use for coughing related to asthma and regular smoking.
  • Dextromethorphan is contraindicated for patients receiving MAOI therapy and taking hepatic disease medications.

Using DXM Effectively

Dextromethorphan provides temporary yet quick and effective relief for coughs. It also performs well with Clonidine, a widely used medication in rehabilitation centers to treat withdrawal symptoms. This particular mechanism of action of DXM makes it a valuable medication to be used in drug abuse treatment programs. The abuse of this drug, however, can lead to serious harm, including seizures and even fatal brain damage. Therefore, it should always be taken at the right dosage directed by a physician.

Page Sources

  1. Linda Garcés-Ramírez, Jennifer L. Green, Takato Hiranita, Theresa A. Kopajtic, Maddalena Mereu, Alexandra Thomas, Christophe Mesangeau, Sanju Narayanan, Christopher R. McCurdy, Jonathan L. Katz, Gianluigi Tanda. Sigma receptor agonists: Receptor binding and effects on mesolimbic dopamine neurotransmission assessed by microdialysis. 2010.
  2. Ayyoub Malek, Shahrokh Amiri, Bohlool Habibi. The Therapeutic Effect of Adding Dextromethorphan to Clonidine for Reducing Symptoms of Opioid Withdrawal: A Randomized Clinical Trial. 2013 Asl.
  3. Weinbroum AA, Rudick V, Paret G, Ben-Abraham R. The role of dextromethorphan in pain control. 2000.
  4. Perry PJ, Fredriksen K, Chew S, Ip EJ, Lopes I, Doroudgar S, Thomas K. The Effects of Dextromethorphan on Driving Performance and the Standardized Field Sobriety Test. 2015.
  5. FDA White Oak Campus. Use of Cough Suppressants in Children. Expert Roundtable Meeting. 2017; 6.

Published on: August 6th, 2019

Updated on: March 16th, 2020

About Author

Peter J. Grinspoon, MD

Dr. Peter Grinspoon is an experienced physician with long-term clinical practice experience. As a former analgesic addict, Dr. Grinspoon knows precisely how important it is to provide patients with effective treatment and support. Medical writing for him is the way to communicate with people and inform them about their health.


Leave a comment