OFSO,
It is not just Beta blockers affected by grapefruit juice. I was on Amlodipine ( a calcium channel blocker) for my so-called hypertension, and that carries a warning on the information sheet to avoid grapefruit juice.
My normal BP was around 140/90 for a long time, which my GP considered borderline, and just advised taking more exercise, avoiding salt, and generally watching my diet. After developing a kidney stone last October, the duty doctor measured my BP at 255/152, and immediately put me on 5mg Amlodipine. That was fine for a while, but then the dose was increased to 10mg, which led to swollen ankles and a severe allergic reaction with urticaria.
It took some steroids to clear that up, and I'm now off the Amlodipine, and onto diuretics!
Funnily enough, I had no symptoms with my normal BP, only when I started taking the medication!. I think I agree with German friend.