selective and non-selective. Selective
beta-blockers, such as metoprolol, act primarily on the Beta-1 receptors in the heart. Non-selective beta-blockers, such as propranolol act on both types of receptors, in both heart and lungs. Propranolol and other medicines in its class are capable of evoking bronchospasm in people with asthma. Metoprolol is selective, but not entirely so; thus, asthma worsens in some people given this “selective” medicine and you may be one of them.