Can histatussin cause shortness of breath?

Histatussin: Histatussin, which is not available in the USA, contains chlorpheniramine, a well tolerated short acting anti-histamine, ammonium chloride, used as an expectorant, and ephedrine for nasal congestion. AC can cause metabolic acidosis which would make you feel short of breath. Ephedrine can cause tachyarrhythmias which would make you feel S.O. B. so the answer is...yes, it's possible.