Why don't we use beta blockers on patient with asthma and coronary disease?

We do: Beta blockers generally exacerbate asthma as they block the receptors that open up the airways. Think albuterol, the mainstay of asthma treatment, is a beta-agonist, or exactly the opposite of the beta-blocker. However, there are selective beta-blockers which act on the heart but not the lungs and may be used relatively safely in patients who have both problems.

See below: Because most asthma patients are on beta agonists (like albuterol) which open bronchial airways by relaxing smooth muscle in the airways. Beta blockers do the reverse and would cause bronchoconstriction and thus worsen asthma or as least block the effects of the beta agonists.