Dextromethorphan hydrobromide

Dextromethorphan Hydrobromide

Dextromethorphan hydrobromide is a medication commonly used as a cough suppressant in over-the-counter cold and cough medicines. It is a synthetic derivative of morphine, but unlike morphine, it does not have analgesic or addictive properties at therapeutic doses. Dextromethorphan is classified as an antitussive, which means it is used to relieve cough.

Pharmacology

Dextromethorphan acts on the central nervous system to suppress the cough reflex. It is an NMDA receptor antagonist and a sigma-1 receptor agonist. At therapeutic doses, it primarily affects the cough center in the medulla oblongata, reducing the urge to cough.

Mechanism of Action

Dextromethorphan works by decreasing the activity of the cough center in the brain. It is believed to exert its effects by binding to and inhibiting the NMDA receptor, which plays a role in the transmission of pain and cough signals. Additionally, dextromethorphan's action on sigma-1 receptors may contribute to its cough-suppressing effects.

Metabolism

Dextromethorphan is metabolized in the liver by the cytochrome P450 enzyme CYP2D6 to dextrorphan, which is an active metabolite. The rate of metabolism can vary significantly between individuals due to genetic polymorphisms in the CYP2D6 enzyme.

Uses

Dextromethorphan is primarily used to treat coughs associated with the common cold, bronchitis, and other respiratory illnesses. It is available in various formulations, including syrups, tablets, and lozenges.

Side Effects

Common side effects of dextromethorphan include dizziness, nausea, and drowsiness. At higher doses, it can cause confusion, excitation, and hallucinations. Abuse of dextromethorphan can lead to serious health issues, including serotonin syndrome and dissociative states.

Abuse Potential

Although dextromethorphan is safe at recommended doses, it has potential for abuse, particularly among adolescents. At high doses, it can produce psychoactive effects, including euphoria and hallucinations, due to its action on the NMDA receptor.

Regulation

In many countries, dextromethorphan is available over-the-counter, but some jurisdictions have imposed age restrictions or require identification for purchase to prevent abuse.

Also see

• Cough suppressant
• NMDA receptor antagonist
• Sigma-1 receptor
• Cytochrome P450
• Serotonin syndrome