(1) Specific classes of medications used to control and slow the heart rate include digitalis , beta blockers, and calcium channel blockers.(2) In reality, more than 30% of conventional medications come from common plant sources (eg, digitalis from foxglove, vincristine from periwinkle).(3) One-year mortality was reduced regardless of gender, presence of diabetes mellitus or heart failure, or treatment with diuretics, digitalis , beta blockers or anticoagulants.(4) The effects of the medication can be inhibited by tricyclic antidepressants and digitalis .(5) According to the authors, the concomitant intake of those two drugs induced a drop in potassium following a diuretic induced decrease in water retention, which led to an increase in sensitivity of heart muscle to digitalis .