Does Lactulose Cause Palpitations And Elevated BP?

i have been on lactulose for several yrs for an inactive colon and colon blockage. gradually it has had to be increased over the yrs. I started with 4 tablespoons and today i take 18 tablespoons nightly recently i have had heart palpatations and my blood pressure has gone to 140/70 . i have been put on metoprolol ER 25mg.once daily. a cartologist said my heart is good......salt runs slightly low 131-132........lactulose is probably doing this but the answer may be the little bag out the side of the body as colon won't work without it.....HELP mssj1234! WWW.WWWW.WW