Atenolol and Verapamil

My sister has recently been put on Atenolol and Verapamil in an effort to control a new onset of high blood pressure.  She has actually been on Atenolol for many years to treat migraine headaches, with some success.  When the high blood pressure occured, the Verapamil was then added.  She has complained of occasional dizziness for quite some time, but this week has become so dizzy that she cannot work or drive and isn't even comfortable ambulating.  Her md has told her stop the Atenolol on Thurs of this week.  She is still very symptomatic as of day 2 with a heart rate in the 60s, which is low for her.  When might she expect her symptoms to subside?  Do these symtoms (symptoms) indicate that this drug combination resulted in some type of toxicity?  She has also had diarrhea and a rash, which she thought was just a random virus at the same time.

[Cleveland Clinic]

The diarrhea is probably getting her a little dehydrated which accentuates the effect of these drugs.  This is not a toxicity.  The atenolol wears of in about 5 days, so she has a few more days left.  I would encourage her to increase her oral intake.