Dear Dr. K; When I recently started taking Coreg for newly diagnosed hypertension my previously well controlled asthma got worse. Are they related?
The short answer is yes, the long answer requires explanation. First of all, asthma and hypertension are both very common conditions with 9% of American adults having asthma and up to 25% having hypertension. Certain factors can contribute to both conditions: stress, obesity, sedentary life style, excess salt intake, and sleep-disturbed sleep. Correcting these factors can help both conditions.
In terms of medications, many of the medicines used to treat asthma and hypertension can act on opposing sides of the autonomic nervous system. The autonomic nervous system controls the smooth muscles found in both our bronchial tubes and our blood vessels and heart. Unfortunately, medicines that can relax heart and blood vessel smooth muscle (thereby lowering BP) can sometimes constrict bronchial smooth muscle (narrowing airways and causing asthma).
Coreg contains a beta-blocker meaning it blocks the beta input into blood vessels and the heart and thereby relaxes them and lowers BP. Unfortunately, it also blocks beta input into bronchial tubes which causes them to tighten, thereby causing asthma. Many of the medications used to treat asthma work through the beta system as stimulants (agonists). Many inhalers contain short acting or long acting beta agonists: albuterol, Advair, Symbicort, Breo, Dulera. Blocking the beta system reduces their benefit.
Luckily scientists have come to understand this dichotomy. This has led to the development of “cardio-selective” beta blockers. These drugs are much less likely to have negative effect on asthma as they are formatted to work mostly on the heart and blood vessels. Perhaps your doctor could switch you from Coreg (a non-cardio selective) to a cardio-selective beta blocker.