ORNACOL

Dextromethorphan is a non-opioid antitussive drug. The major metabolite of dextromethorphan, dextrorphan, binds with high affinity to σ-receptors to produce its antitussive activity without exhibiting the classic opiate effects that occur from binding into μ- and δ-receptors. In larger than therapeutic doses, dextrorphan is also an antagonist of N-methyl-D-aspartate (NMDA) receptors.

Phenylpropanolamine is a sympathomimetic agent which is used as a decongestant and appetite suppressant. It was commonly used in prescription and over-the-counter cough and cold preparations. Although originally thought to act as a direct agonist of adrenergic receptors, phenylpropanolamine was subsequently found to show only weak or negligible affinity for these receptors, and has been instead characterized as an indirect sympathomimetic which acts by inducing norepinephrine release and thereby activating adrenergic receptors.