I wouldn't worry about polyvinyl alcohol triggering CH...  Many years ago while getting my degree in chemistry at the U of W in Seattle, I worked at a plastics factory where we used polyvinyl alcohol as a release agent to keep the GelCoat finish on fiberglass boats from sticking to the mold. 

We applied the polyvinyl alcohol with a spray gun to the inside of the mold so used eye protection and mask to prevent inhaling the polyvinyl alcohol. This was well before OSHA so I used the chem lab's CRC Handbook and Merck Index to make sure it wasn't hazardous... 

Polyvinyl alcohol is used in eye drops and contact lens wetting solutions in small quantities.  It also appears it's used as a binding agent in some pill form medications, but the quantity is so small I doubt there's much to be concerned about. 

The body metabolizes/oxidizes polyvinyl alcohol in the liver through a number of processes to acetic acid... vinegar, much the same as the ethyl alcohol (ethanol) in beer, wine, and hard liquor... 

As ethyl alcohol is induces cerebrovascular constriction, I'm of the opinion the rapid conversion in the liver to acetic acid may be one of the mechanisms that triggers CH as acetic acid lowers arterial pH and that causes vasodilation. 

Is the medication Tramadol?

Take care,

V/R, Batch