Beta blockers are medicines that are often used in the treatment of high blood pressure and heart complaints. They slow the heart rate and block the sometimes harmful effects of stress hormones on the heart. There can be problems in combining beta blockers with asthma, as these medications can cause asthma attacks. If taking a beta blocker has been judged essential, then it is important that the impact on the asthma sufferer is monitored closely.
The purpose of using beta blockers is to treat high blood pressure, irregular and/or fast heartbeats, angina, congestive heart failure, migraines and overactive thyroid glands. They block the effect of adrenaline on the body's beta receptors and slow the nerve impulses that travel through the heart. There are two types of beta receptors, beta 1 and beta 2, and there are two types of beta blockers. The older medications are called non-selective, as they target both beta 1 and beta 2. The newer ones are called cardio selective beta blockers, as they block beta 1 more than beta 2, and thus are more precise in their actions.
The development of the cardio selective type is good news for asthma sufferers. The use of these beta blockers with mild or moderate asthma is considered much safer for the airways. For those who suffer from severe asthma, however, the use of beta blockers is not advisable.
Potential adverse effects of beta blockers with asthma patients were originally documented on the use of the non-selective type, where acute bronchospasms were reported as a side effect. A bronchospasm is a contraction of the smooth muscle of the bronchi and bronchioles, which leads to an obstructed respiratory airway. This is a chief characteristic of asthma. The relationship of beta blockers with asthma was not researched or examined in any other formal way, but the idea that the two do not mix became entrenched.
The subsequent development of the newer cardio selective beta blocker, which has largely replaced the older medication in popularity, has resulted in a revision of the wisdom of taking beta blockers with asthma. It has been found that when the newer type of medication is taken at therapeutic doses, the risk of bronchospasms is negligible. This means that the use of cardio selective beta blockers with asthma is deemed less risky and may even be beneficial.
As of May 2011, more research needs to be done on the relationship between asthma and beta blockers, but medical opinion mainly supports the use of cardio selective beta blockers for patients with mild or moderate asthma. Such patients should be closely monitored while the treatment is in effect. There is little data available on the efficacy of using beta blockers on people with severe asthma.