Hello, Thank you for your query. Nebicard is a selective beta blocker which means that its effect is mainly on the heart and blood vessels and not on the bronchial tree of the lungs. It loses this selectivity in doses higher than 5mg per day or if you are a slow metabolizer . If your asthma was diagnosed on the basis of a spirometry and you require a reliever like ventorlin, then you should avoid Nebicard in doses above 5mg per day because there is a risk of precipitating asthma. There are many antihypertensives that do not have this risk and your doctor can advise you something that has no effect on the lungs. I am available if you have further queries. Dr. Noble Zachariah