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

Choice A reason: This is not an adverse effect of ACE inhibitors. Constipation is a common side effect of opioid medications, which slow down the intestinal motility and cause hard stools.

Choice B reason: This is not an adverse effect of ACE inhibitors. Hypokalemia is a low level of potassium in the blood, which can be caused by diuretic medications, such as furosemide or hydrochlorothiazide, which increase the urine output and potassium excretion.

Choice C reason: This is an adverse effect of ACE inhibitors. Chronic cough is a dry, persistent cough that occurs in some patients taking ACE inhibitors, due to the accumulation of bradykinin, a substance that causes inflammation and irritation in the respiratory tract.

Choice D reason: This is not an adverse effect of ACE inhibitors. Nervousness is a common side effect of stimulant medications, such as caffeine or amphetamine, which increase the activity of the central nervous system and cause anxiety, agitation, and insomnia.

Choice A reason: Vasodilators are not the preferred agents for the initial treatment of heart failure. They are used as adjunctive therapy to reduce the afterload and preload on the heart. However, they do not address the fluid overload that is the main cause of heart failure symptoms.

Choice B reason: Diuretics are the preferred agents for the initial treatment of heart failure. They help to reduce the fluid overload and congestion in the lungs and peripheral tissues. They also lower the blood pressure and improve the cardiac output and renal function.

Choice C reason: Calcium channel blockers are not the preferred agents for the initial treatment of heart failure. They are contraindicated in most cases of heart failure because they can worsen the cardiac function and increase the mortality. They can also cause peripheral edema and hypotension.

Choice D reason: Direct renin inhibitors are not the preferred agents for the initial treatment of heart failure. They are a newer class of drugs that block the renin-angiotensin-aldosterone system (RAAS), which is involved in the pathophysiology of heart failure. However, they have not shown any significant benefit over the existing RAAS inhibitors, such as angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs). They can also cause hyperkalemia and renal impairment.