COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Pharmacology Questions and Answers

Question 1

A 68-year-old male with a history of heart failure with reduced ejection fraction and concurrent atrial fibrillation is being managed medically. His physician adds a medication that works by inhibiting the Na+/K+-ATPase pump in myocardial cells. This action leads to an increase in intracellular calcium. Which of the following effects is the primary therapeutic goal of this medication in this patient?

Accepted Answer

Increased myocardial contractility and decreased atrioventricular (AV) node conduction

Answer

The medication described is digoxin. Its primary mechanism is the inhibition of the Na+/K+-ATPase pump, which increases intracellular sodium. This, in turn, reduces the activity of the Na+/Ca2+ exchanger, leading to increased intracellular calcium and thus stronger myocardial contractions (positive inotropy). Additionally, digoxin has a parasympathomimetic effect that slows conduction through the AV node, which is therapeutic for controlling the ventricular rate in atrial fibrillation.

Question 2

A 45-year-old male is being treated for a severe MRSA infection with intravenous vancomycin. During the infusion, he develops diffuse erythema and flushing of his face, neck, and upper torso, accompanied by pruritus and mild hypotension. What is the most likely direct cause of this reaction?

Accepted Answer

Direct degranulation of mast cells and basophils

Answer

This patient is experiencing Vancomycin Infusion Reaction (VIR), also known as red man syndrome. This is an anaphylactoid reaction, not a true allergic (IgE-mediated) reaction. It is caused by the rapid infusion of vancomycin, which directly stimulates mast cells and basophils to release histamine, leading to the characteristic flushing, erythema, and pruritus.

Question 3

A 55-year-old female with type 2 diabetes mellitus is started on empagliflozin. Which of the following best describes the primary mechanism of action of this medication?

Accepted Answer

It inhibits glucose reabsorption in the proximal convoluted tubule.

Answer

Empagliflozin is a sodium-glucose cotransporter-2 (SGLT2) inhibitor. SGLT2 is responsible for reabsorbing the majority of filtered glucose from the tubular fluid back into the blood in the proximal convoluted tubule of the kidney. By inhibiting this transporter, empagliflozin promotes the excretion of glucose in the urine, thereby lowering blood glucose levels.

Question 4

A farmworker is brought to the emergency department with confusion, pinpoint pupils, profuse sweating, and muscle fasciculations. He is bradycardic and hypotensive. These symptoms are characteristic of poisoning by an agent that causes which of the following?

Accepted Answer

Inhibition of acetylcholinesterase

Answer

This clinical presentation is classic for organophosphate poisoning, which is common in agricultural settings. Organophosphates are irreversible inhibitors of acetylcholinesterase (AChE). Inhibition of AChE leads to an accumulation of acetylcholine at both muscarinic and nicotinic synapses, causing a cholinergic crisis with symptoms like miosis, salivation, lacrimation, urination, defecation, GI distress, emesis (DUMBELS), as well as muscle fasciculations and weakness.

Question 5

A 62-year-old male with chronic back pain has been managed with long-term, high-dose opioid therapy. While patients typically develop tolerance to many side effects of opioids, which of the following adverse effects is least likely to diminish over time?

Accepted Answer

Constipation

Answer

While tolerance develops to most of the central nervous system effects of opioids, such as sedation, euphoria, and respiratory depression, tolerance to the gastrointestinal effects, particularly constipation, develops very slowly or not at all. Opioids decrease GI motility and secretions, leading to persistent constipation that often requires proactive management throughout the duration of therapy.

COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Practice Test

COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Practice Test

COMSAE - Comprehensive Osteopathic Medical Self-Assessment Examination Pharmacology Questions and Answers