I originally got on it for its well known side effect of slowing the
heart rate. I was unknowingly suffereing from severe sleep apnea at the time,
and was awakening each nght with a pounding, elevated heart rate, but not tachycardia. I kept increasing the dosage until I was at 200mg. This slowed my heart sufficiently, but I was a zombie, and any exertion felt like a weight on my chest. After discovering the sleep apnea, I got on CPAP, lowered the dosage to 100mg, and felt much better.