Dextromethorphan

[SH4:p175]

Usage

• Common in over-the-counter cough suppressants

Structure

• D-isomer of levorphanol

Pharmacodynamics

Mechanism of action

• A low affinity NMDA antagonist

Effects

• Equal in antitussive potency as codeine
• NO analgesic or physical dependence action
• Rarely cause sedation or GIT problems

Side effects/Toxicity

Side effects

• Euphoric effects can lead to abuse

Toxicity

In the case of overdose, the symptoms and signs include:

• Increased BP
• Increased HR
• Somnolence/Agitation/Coma
• Slurred speech
• Ataxia
• Diaphoresis
• Skeletal muscle rigidity
• Seizure
• Decreased core temperature