Dextromethorphan

Dextromethorphan received approval from the U.S. Food and Drug Administration (FDA) in 1958.¹ It was created as part of an initiative to find a non-addictive substitute for opioid-based cough medicines. Although a synthetic derivative of morphine, it has a vastly different range of medical effects.

Dextromethorphan acts on the central nervous system (CNS) to suppress the urge to cough. Specifically, it impacts sigma-1 and N-methyl-D-aspartate (NMDA) receptors. ¹

DXM is effective in relieving coughs at recommended dosages and is generally well-tolerated with a low profile of side effects, such as dizziness, gastrointestinal discomfort, and drowsiness.²

When consumed at considerably higher dosages, dextromethorphan can produce dissociative or even hallucinogenic effects. Concerns about its misuse, especially among adolescents, have grown due to these psychoactive properties.³ Additionally, when taken with certain medications like isocarboxazid and metaxalone, there could be a risk of severe adverse interactions.⁵

Because of increasing concerns about misuse, there have been calls for stricter regulation. Some states in the U.S. have implemented age restrictions for purchasing products containing dextromethorphan.⁴

Appearance

In its pure form, dextromethorphan is usually a white powder. However, it is most commonly encountered in various over-the-counter products. For example:

• Syrups: Typically clear to slightly opaque, with varying colours like red, green, or purple.
• Capsules and Tablets: Usually white or a combination of colours, and may be solid or filled with powder or liquid.
• Lozenges: Usually circular and come in various colours.

Tastе

The taste of dextromethorphan also varies based on the product.

• Syrups: Usually sweetened and flavoured to mask the bitter taste of the active ingredient.
• Capsules and Tablets: Generally do not have a taste unless broken open, as they are meant to be swallowed whole.
• Lozenges: Often flavoured with menthol, eucalyptus, or fruit flavours to make them palatable.

Smell

Dextromethorphan itself is generally odourless. However, the syrups, capsules, and lozenges often have added flavours or ingredients that may contribute to a mild scent. For example, syrups may have a fruity or medicinal smell depending on the other ingredients present.

These characteristics can be found in various consumer-facing product descriptions and medical literature.^2,4

Dosage can differ based on the specific product form and individual requirements. The dosages outlined below are generally recommended for therapeutic use in adults:

• Syrups: 15-30 mg every 4 to 6 hours.
• Tablets/Capsules: Similar to syrups, although it is imperative to follow the manufacturer’s instructions. ²
• Recreational Use: For recreational use, the following dosages have been reported, though it’s essential to note that these are not medically recommended and can be dangerous:
• Minimum to Feel Something: Around 100 mg is often reported to produce mild stimulation.
• Low Dose: The 100-200 mg range, where users may experience heightened sociability and euphoria.
• Common Dose: Between 200-400 mg, typically producing noticeable perceptual changes and increased dissociative effects.
• High Dose: Over 600 mg, posing a considerable risk of severe adverse effects, such as hallucinations and hyperthermia. ³

What May Happen When Exceeding the High Dose

Exceeding high doses of Dextromethorphan (DXM) can lead to a range of severe health risks. These include but are not limited to hallucinations, hyperthermia, serotonin syndrome, severe dissociative states, and even death in extreme cases. ³

Users report a range of sensations depending on the dose:

Lower doses may produce mild euphoria and increased sociability.

Higher doses can lead to altered states of consciousness, including intense visual and auditory hallucinations and dissociative states.³

DXM generally takes about 30 minutes to an hour to start showing effects after oral consumption.¹

The effects of DXM generally last between 4 to 6 hours, although this can vary based on individual metabolism and dosage.²

Significant risks include serotonin syndrome, a potentially life-threatening condition, as well as damage to the liver due to the presence of other ingredients like acetaminophen in some formulations. ³

DXM is generally considered to have a low potential for addiction when used as directed. However, problematic use can arise when taken in excessive amounts for its psychoactive effects.³

In the United Kingdom, Dextromethorphan (DXM) is legally available over-the-counter. It is not classified under the Misuse of Drugs Act 1971, which means you can purchase and possess it without requiring a prescription. Nevertheless, misuse or selling to minors could result in legal consequences. Always follow the guidelines provided by the manufacturer and consult with healthcare professionals for appropriate use.

Significant interactions have been reported when DXM is mixed with other drugs like MAOIs, SSRIs, and certain analgesics, leading to severe health risks like serotonin syndrome.⁵

1. DrugBank. (n.d.). Dextromethorphan. Retrieved from https://go.drugbank.com/drugs/DB00514)
2. NCBI Bookshelf. (n.d.). Dextromethorphan Hydrobromide. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK538216/)
3. Substance Abuse Policy. (2016). Dextromethorphan abuse in adolescence. Retrieved from https://substanceabusepolicy.biomedcentral.com/articles/10.1186/s13011-016-0067-0)
4. Justice.gov. (n.d.). Dextromethorphan. Retrieved from https://www.justice.gov/archive/ndic/pubs11/11563/index.htm#Sources )
5. WebMD. (n.d.). Dextromethorphan HBR Oral. Retrieved from https://www.webmd.com/drugs/2/drug-363/dextromethorphan-hbr-oral/details)