The first generation of nonselective beta blockers for the treatment of asthma have been long been declared obsolete, and the modern cardio selective beta blockers are now in use almost everywhere. They are immensely more suitable for selectively blocking beta-2 receptors within the body while affecting the beta-1 receptors as little as possible. Controlled doses of cardio selective beta blockers can reduce the risks of bronchoconstriction tremendously. Beta blockage also causes the beta regulators to become much more sensitive to any form of adrenergic stimulation.

Cardio selective beta blockers work by neutralizing the effect of adrenaline in the human body. Patients of mild to moderate stages of asthma and other breathing-related diseases can safely use cardio selective beta blockers without the risk of having to deal with unwanted asthmatic seizures. The older generations of beta blockers were rarely prescribed to patients due to their 'uncontrollable' nature, but the precision offered by the new beta blockers make them suitable for widespread use, as seen from extensive research conducted on the matter. However, they are still unsuitable for treating cases of severe asthma, in cases of which, different alternatives are explored.