Question

1. A 48-year-old man asks his physician for a prescription for sildenafil to improve his sexual performance. Because of risks from a serious drug interaction, this drug should not be prescribed and the patient should be urged not to try to obtain it from other sources, if he is also taking which of the following drugs?

A. Angiotensin-converting enzyme inhibitor

B. Beta-adrenergic blocker

C. Nitrovasodilator (eg. Nitroglycerin)

D. Thiazide or loop diuretic

2. A patient with heart failure, hypertension and hyperlipidemia is taking furosemide, captopril, atenolol, and simvastatin. During a scheduled physical examination, about a month after starting all the drugs, the patient reports a severe, hacking and relentless cough. Which of the following is the most likely cause of the cough?

A. An expected effect of the captopril

B. An allergic reaction to the statin

C. Dyspnea due to captopril's bronchoconstrictor action

D. Hyperkalemia caused by an interaction between furosemide and captopril

E. Excessive doses of furosemide, which lead to hypovolemia

3. Flecainide and propafenone are in Vaughan-Williams (antiarrhythmic) Class I-C. What is the clinically relevant "take home" message about this class of drugs?

A. Are only given for arrhythmias during acute myocardial infarction (MI)

B. Are particularly suited for patients with low ejection fraction or cardiac output

C. Are preferred drugs for relatively non-severe ventricular arrhythmias

D. Have a significant pro-arrhythmic effect (induction of lethal arrhythmias)

E. Cause pulmonary fibrosis and a hypo-thyroid syndrome when given long term.

Answer 1

1. Sildenafil potentiates the hypotensive effects of nitrates. Hence, it's administration to persons who are using nitrates in any form is dangerous.

Therefore, option C is correct.

Sildenafil should not be prescribed if the patient is taking nitrovasodilator(eg. Nitroglycerin)

2. Common adverse effect of prolonged use of captopril is persistent dry cough.

It is believed to be due to raised bradykinin. ACE inhibitors not only inhibit the action of ACE, but also inhibit the breakdown of bradykinin.

This results in the accumulation of protussive mediators like bradykinin leading to dry cough.

Therefore, option A is correct.

Severe, hacking and relentless cough is an expected effect of captopril.

3. These drugs are only given for arrhythmias during acute myocardial infarction (MI).

They have a significant pro-arrhythmic effect (induction of lethal arrhythmias).

Class-1 C antiarrhythmics such as flecainide and propafenone are contraindicated as they are pro-arrhythmic and may precipitate ventricular fibrillation.

Therefore, option D is correct.