(±)-Bisoprolol (hemifumarate) is a selective type β1 adrenergic receptor blocker. Target: Adrenergic Receptor Approved: July 31, 1992 Bisoprolol, on beta 1-adrenoceptor peptide induced autoimmune myocardial damage. In the animal model of autoimmune cardiomyopathy induced by active immunization of rabbits with beta 1-adrenoceptor peptide, bisoprolol was given at a dose of 3 mg/day throughout the study period. Our results showed high titer of anti-beta 1-adrenoceptor antibody in the immunized group throughout the study but not in the group receiving only bisoprolol [1]. Bisoprolol administration resulted in a significant reduction in HR reaching 60.3 +/- 1.4 bpm at VT of 500 mL (compared to 70.5 +/- 1.8 bpm with placebo, P < 0.001). Changes in HP were also significant with an increase in HP reaching 1004.5 +/- 22.2 msec at this controlled VT (compared to 860.3 +/- 21.5 msec with placebo, P < 0.001) [2]. Toxicity: Oral, mouse: LD50 = 100 mg/kg; Skin, rabbit: LD50 = 200 mg/kg; Skin, rat: LD50 = 500 mg/kg. Symptoms of overdose include congestive heart failure (marked by sudden weight gain, swelling of the legs, feet, and ankles, fatigue, and shortness of breath), difficult or labored breathing, low blood pressure, low blood sugar, and slow heartbeat.