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

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.

Choice A reason: This is not the agent that the nurse should question. Beta blockers are a class of medications that lower the blood pressure and heart rate by blocking the beta receptors in the heart and blood vessels. They can be used to treat hypertension, angina, heart failure, and arrhythmias. They do not cause edema or hyperkalemia.

Choice B reason: This is not the agent that the nurse should question. Alpha 2 agonists are a class of medications that lower the blood pressure by stimulating the alpha 2 receptors in the brain, which reduce the sympathetic nervous system activity. They can be used to treat hypertension, especially in patients with renal impairment. They do not cause edema or hyperkalemia.

Choice C reason: This is not the agent that the nurse should question. Calcium channel blockers are a class of medications that lower the blood pressure and heart rate by blocking the calcium channels in the heart and blood vessels, which cause vasodilation and reduced cardiac contractility. They can be used to treat hypertension, angina, and arrhythmias. They may cause edema, but not hyperkalemia.

Choice D reason: This is the agent that the nurse should question. Aldosterone antagonists are a class of medications that lower the blood pressure and reduce fluid retention by blocking the action of aldosterone, a hormone that regulates the sodium and potassium balance in the body. They can be used to treat hypertension and heart failure, especially in patients with low renin levels. However, they can cause hyperkalemia, which can be dangerous for the patient. The nurse should question the prescriber about the rationale for prescribing this agent and monitor the patient's potassium level closely.