An elderly man, in obvious respiratory distress due to exacerbation of his emphysema and chronic bronchitis, presents in the emergency department. One drug ordered by the physician, to be administered by respiratory therapist, is $N$-acetylcysteine. Which of the following is main action or purpose of this drug?

An elderly man, in obvious respiratory distress due to exacerbation of his emphysema and chronic bronchitis, presents in the emergency department. One drug ordered by the physician, to be administered by respiratory therapist, is $N$-acetylcysteine. Which of the following is main action or purpose of this drug?

Toxicities of H₁ antihistamines include which one of the following?

Acute exacerbations of asthma can be triggered by all of the following except

The symptoms of allergen-mediated asthma result from which of the following?

Terbutaline has a preference for stimulation of which of the following receptors?