How does montelukast (Singulair), a leukotriene blocker, work in the treatment of asthma?

Choice A reason: This is not what will happen when a person is hypotensive. Baroreceptors are sensory receptors that detect changes in blood pressure. When a person is hypotensive, the baroreceptors are more active, not less, and they send signals to the brain to increase the blood pressure.

Choice B reason: This is what will happen when a person is hypotensive. SNS stands for sympathetic nervous system, which is the part of the autonomic nervous system that prepares the body for fight or flight response. When a person is hypotensive, the SNS is activated to increase the heart rate, contractility, and vasoconstriction, which all raise the blood pressure.

Choice C reason: This is not what will happen when a person is hypotensive. Person will be bradycardic means that the person will have a slow heart rate, usually below 60 beats per minute. When a person is hypotensive, the opposite will happen, as the heart rate will increase to compensate for the low blood pressure.

Choice D reason: This is not what will happen when a person is hypotensive. SNS is suppressed means that the sympathetic nervous system is inhibited or reduced in activity. When a person is hypotensive, the SNS is not suppressed, but rather stimulated, to increase the blood pressure.

Choice A reason: This is not a correct statement. LABAs stand for long-acting beta2-agonists, which are a class of medications that relax the smooth muscles of the airways and improve the airflow in patients with asthma or COPD. However, LABAs do not reduce the risk of asthma-related deaths, and may even increase it if used alone without an inhaled glucocorticoid, which is a type of anti-inflammatory medication.

Choice B reason: This is not a correct statement. LABAs cannot be used on an as-needed basis to treat symptoms, as they have a slow onset of action and a long duration of effect. LABAs are meant to be used as a maintenance therapy to prevent asthma exacerbations, not to relieve acute symptoms. For quick relief of symptoms, patients should use a short-acting beta2-agonist, such as albuterol or salbutamol.

Choice C reason: This is not a correct statement. LABAs are not safer than short-acting beta2 agonists, as they have similar side effects, such as tachycardia, tremors, and hypokalemia. LABAs also have a black box warning that they may increase the risk of asthma-related deaths if used without an inhaled glucocorticoid.

Choice D reason: This is the correct statement. LABAs should be combined with an inhaled glucocorticoid, as this combination has been shown to improve the asthma control, reduce the frequency and severity of exacerbations, and decrease the inflammation and airway hyperresponsiveness. The inhaled glucocorticoid also reduces the risk of adverse effects and mortality associated with LABAs.