Dxm

Dxm
INN
Drug class
Routes of administration	Oral
Pregnancy category
Bioavailability	11%
Metabolism	Hepatic (CYP2D6, CYP3A4)
Elimination half-life	2-4 hours
Excretion	Renal
Legal status
CAS Number	125-71-3
PubChem	5284443
DrugBank	DB00514
ChemSpider	4447628
KEGG	D03778

Dextromethorphan (DXM) is a medication most commonly used as a cough suppressant in over-the-counter cold and cough medicines. It is a dissociative drug of the morphinan class with multiple mechanisms of action, including effects on the central nervous system.

Pharmacology

Dextromethorphan is a non-opioid cough suppressant that acts on the medulla oblongata to elevate the threshold for coughing. It is a stereoisomer of levomethorphan, an opioid analgesic, but lacks significant analgesic or addictive properties at therapeutic doses.

Mechanism of Action

Dextromethorphan primarily acts as a sigma-1 receptor agonist and an NMDA receptor antagonist. It also has activity as a serotonin reuptake inhibitor and a norepinephrine reuptake inhibitor. These actions contribute to its antitussive effects and its potential for abuse at higher doses.

Metabolism

Dextromethorphan is metabolized in the liver by the cytochrome P450 enzyme CYP2D6 to dextrorphan, which is also an active metabolite. The drug is further metabolized by CYP3A4. Genetic polymorphisms in CYP2D6 can lead to variations in metabolism, affecting the drug's efficacy and risk of side effects.

Clinical Uses

Dextromethorphan is used to relieve cough caused by the common cold, influenza, or other respiratory conditions. It is available in various formulations, including syrups, lozenges, and capsules.

Adverse Effects

At therapeutic doses, dextromethorphan is generally well-tolerated. Common side effects include dizziness, nausea, and drowsiness. At higher doses, it can cause hallucinations, dissociation, and euphoria, leading to its potential for abuse.

Abuse Potential

Dextromethorphan is sometimes abused for its psychoactive effects. High doses can lead to dissociative states similar to those produced by ketamine or phencyclidine (PCP). Abuse of dextromethorphan is sometimes referred to as "robotripping" or "skittling."

Legal Status

Dextromethorphan is available over-the-counter in many countries, but some jurisdictions have imposed restrictions due to its abuse potential. In the United States, it is available without a prescription, but some states have age restrictions on its purchase.

See Also

• Cough suppressant
• Dissociative drug
• NMDA receptor antagonist

External Links

• Drugs.com: Dextromethorphan
• MedlinePlus: Dextromethorphan