A 60-year-old man with known coronary artery disease comes to the office due to exertional chest tightness for the last 6 months. The symptoms occur when he walks more than 3 blocks, especially in cold weather. The patient underwent coronary artery bypass graft surgery 3 years ago for progressive angina. Past medical history also includes asthma, benign prostate hyperplasia, and peripheral artery disease. The physician discusses adding isosorbide dinitrate to his current therapy but the patient is concerned about adverse effects. Which of the following is most likely to occur in this patient with the add-on therapy?

Question

A 60-year-old man with known coronary artery disease comes to the office due to exertional chest tightness for the last 6 months.  The symptoms occur when he walks more than 3 blocks, especially in cold weather.  The patient underwent coronary artery bypass graft surgery 3 years ago for progressive angina.  Past medical history also includes asthma, benign prostate hyperplasia, and peripheral artery disease.  The physician discusses adding isosorbide dinitrate to his current therapy but the patient is concerned about adverse effects.  Which of the following is most likely to occur in this patient with the add-on therapy?

Quizplus · Accepted Answer

Nitrates are frequently used for symptomatic relief in patients with chronic stable angina. The anti-ischemic effect of nitrates is mediated by systemic vasodilation (predominantly venodilation) with a decrease in left ventricular end-diastolic volume and wall stress, resulting in decreased myocardial oxygen demand and relief of angina symptoms. The main adverse effects seen with nitrate therapy include headaches, cutaneous flushing, lightheadedness, hypotension, and reflex tachycardia. Nitrates must be avoided in patients with hypertrophic cardiomyopathy (due to increased outflow tract obstruction), right ventricular infarction (due to reduction in preload, impairing cardiac output), and those on phosphodiesterase inhibitors (synergism increases the risk of severe hypotension). (Choice A) Atrioventricular conduction delay is a potential adverse effect of several drugs used for management of chronic stable angina. These include calcium channel blockers (eg, verapamil, diltiazem) and beta blockers (eg, metoprolol, propranolol). (Choice B) Cold extremities due to Raynaud phenomenon are associated with medications such as amphetamines, ergotamine, and chemotherapeutic agents. (Choice C) Constipation is a common side effect of opioid analgesics, iron supplements, calcium channel blockers such as verapamil, and anticholinergic medications such as atropine. (Choice D) Thiazide diuretics can lead to hyperuricemia and precipitate an acute gout attack. (Choice E) Nocturnal wheezing can be a symptom of asthma or gastroesophageal reflux disease. In addition, the use of beta blockers in patients with underlying bronchospastic disease can cause increased bronchoconstriction and lead to wheezing. (Choice G) Urinary retention is typically associated with medications that exhibit anticholinergic properties such as tricyclic antidepressants (eg, amitriptyline) and antihistamines (eg, diphenhydramine). Educational objective: The main adverse effects seen with nitrate therapy include headaches and cutaneous flushing along with lightheadedness and hypotension due to systemic vasodilation. __________ References: Mechanisms of action of nitrates. (http://www.ncbi.nlm.nih.gov/pubmed/7873467)

A 60-Year-Old Man with Known Coronary Artery Disease Comes to the Office