Dextromethorphan differs from codeine in:
Dextromethorphan is a synthetic opiod derivative with antitussuive actions like codeine but with lesser side effects. It does not cause constipation and has no addiction liability but can cause nausea and drowsiness. Ref KD Tripathi 8th ed.
Its antitussive action can be blocked by naloxone
Depresses mucocilliary function of the airway mucosa
Addiction common
Causes no constipation
Central Nervous system