Serum half-life for carbinoxamine is estimated to be 10 to 20 hours. Virtually, no intact drug is excreted in the urine. Pseudoephedrine HCl is an oral sympathomimetic amine which acts as a decongestant to respiratory tract mucous membranes. While its vasoconstrictor action is similar to that of ephedrine, pseudoephedrine has less pressor effect in normotensive adults. Serum half-life for pseudoephedrine is 6 to 8 hours.
Acidic urine is associated with faster elimination of the drug.
About one half of the administered dose is excreted in the urine. Dextromethorphan hydrobromide is a non-narcotic antitussive with effectiveness equal to codeine. It acts in the medulla oblongata to elevate the cough threshold. Dextromethorphan does not produce analgesia or induce intolerance, and has no potential for addiction. At usual doses, it will not depress respiration or inhibit ciliary activity.