Sinus / Throat Problems and Pseodophrine

Hello, I have sinus problems which the drainage down the
back of my throat makes my throat irritated and then I cough
horribly. It is a dry high pitched cough. I have been taking
Allegra D which seems to maybe help. Also other medicine
with I have been on contains pseodophrine (SP) but it seems
like it affects my performance in bed when I am on them. Is
this possible ? I am only 34 years old and I am able to
perform very well with my wife when I am not on these meds
but as soon as I start taking them. I only get to the point
of "semi hard" for the lack of words please excuse me if
this offends anyone. I am still able to have an orgasm but
not a full erection.As this is embarrasing enough for me
anyhow and makes me feel less of a man in bed when this
happens. So, I hate to take them. I am just wondering if
there is any other medicine I can use that won't have this
effect on me ? Thanks, Raz

BTw After I get done taking the meds , after a couple of
days I am back to normal.