COMSAE Phase 1 Form 116 Practice Exam With
Actual Questions & Verified Answers, Plus Explained
Rationales/Expert Verified For Guaranteed 100%
Pass 2026/Latest Update/Instant Download Pdf
1. In the context of osteopathic manipulative treatment (OMT), which of the following best
describes the mechanism by which myofascial release improves somatic dysfunction?
A. Inhibition of nociceptive afferents via descending pain modulatory pathways
B. Stretching of shortened fascia to restore tissue fluid dynamics and reduce sympathetic tone
C. Activation of Golgi tendon organs leading to autogenic inhibition of muscle spindles
D. Direct mechanical realignment of vertebral segments through high-velocity thrust
Answer: B
Rationale: Myofascial release targets fascial restrictions; stretching the fascia improves fluid flow and
reduces sympathetic nervous system hyperactivity. Option A describes counterstimulation or
acupuncture-like effects, not myofascial release. Option C is the mechanism for muscle energy
technique. Option D describes high-velocity low-amplitude (HVLA) thrust.
2. A researcher isolates a novel Gram-negative bacterium from a patient with ventilator-associated
pneumonia. The organism produces a beta-lactamase that hydrolyzes ceftazidime but not cefepime.
Which of the following mechanisms is most likely responsible?
A. ESBL (Extended-Spectrum Beta-Lactamase) production
B. AmpC beta-lactamase hyperproduction
C. KPC (Klebsiella pneumoniae carbapenemase) production
D. OXA-48-type carbapenemase
Answer: B
Rationale: AmpC beta-lactamases hydrolyze cephalosporins like ceftazidime but are less active against
cefepime. ESBLs (A) are inhibited by clavulanate and typically hydrolyze cefepime. KPC (C) and
OXA-48 (D) are carbapenemases that hydrolyze carbapenems, not just ceftazidime.
3. In a patient with chronic obstructive pulmonary disease (COPD) and cor pulmonale, which of
the following hemodynamic changes is most likely to be observed on right heart catheterization?
A. Decreased pulmonary capillary wedge pressure and increased cardiac output
B. Increased pulmonary artery pressure and decreased right ventricular ejection fraction
C. Decreased right atrial pressure and increased pulmonary vascular resistance
D. Increased left ventricular end-diastolic pressure and decreased systemic vascular resistance
Answer: B
Rationale: Cor pulmonale results from pulmonary hypertension, causing increased pulmonary artery
pressure and reduced right ventricular function. Wedge pressure (A) is normal in cor pulmonale (no left
Page 1
,heart disease). Right atrial pressure is increased, not decreased (C). Left-sided pressures (D) are normal
unless concomitant left heart disease exists.
4. A 30-year-old individual with a history of recurrent sinopulmonary infections and
bronchiectasis is found to have situs inversus totalis. Which of the following cellular defects is most
likely responsible for this condition?
A. Defective chloride transport due to CFTR mutation
B. Impaired ciliary motility due to dynein arm deficiency
C. Abnormal surfactant production due to SP-B deficiency
D. Deficiency of alpha-1 antitrypsin leading to protease imbalance
Answer: B
Rationale: The combination of situs inversus, bronchiectasis, and sinusitis is characteristic of primary
ciliary dyskinesia (Kartagener's syndrome), caused by defective dynein arms impairing ciliary motility.
CFTR mutation (A) causes cystic fibrosis but not situs inversus. Surfactant deficiency (C) causes
neonatal respiratory distress. Alpha-1 antitrypsin deficiency (D) causes emphysema and liver disease.
5. Which of the following best explains why a patient with chronic kidney disease (CKD) stage 4
develops hyperphosphatemia despite a normal dietary phosphate intake?
A. Increased renal tubular reabsorption of phosphate due to elevated 1,25-dihydroxyvitamin D
B. Decreased glomerular filtration of phosphate leading to reduced phosphate excretion
C. Increased bone resorption of phosphate secondary to secondary hyperparathyroidism
D. Decreased intestinal phosphate binding due to reduced gastric acid secretion
Answer: B
Rationale: In advanced CKD, reduced nephron mass decreases phosphate filtration, causing retention.
Option A is incorrect because 1,25-vitamin D is low in CKD, not high. Option C contributes but is
secondary; the primary defect is renal excretion. Option D is not a major factor; intestinal absorption is
normal.
6. A 45-year-old man presents with acute onset of severe epigastric pain radiating to the back,
nausea, and vomiting. Serum lipase is elevated. Which of the following laboratory findings would
most strongly suggest a biliary etiology?
A. Elevated serum amylase with normal lipase
B. Elevated alanine aminotransferase (ALT) greater than 3 times the upper limit of normal
C. Elevated direct bilirubin with normal alkaline phosphatase
D. Elevated serum triglycerides (1500 mg/dL)
Answer: B
Rationale: In gallstone pancreatitis, transient elevation of ALT >3x normal is common due to passage of
a stone through the ampulla. Amylase and lipase are both elevated, not just amylase (A). Direct bilirubin
may be elevated but alkaline phosphatase is also typically elevated (C). Hypertriglyceridemia (D) is an
etiology itself but not a marker of biliary origin.
Page 2
,7. Which of the following pharmacokinetic changes is most characteristic of drugs that undergo
extensive first-pass metabolism when administered orally?
A. Increased volume of distribution
B. Reduced bioavailability
C. Prolonged elimination half-life
D. Decreased protein binding
Answer: B
Rationale: First-pass metabolism reduces the fraction of an oral dose reaching systemic circulation, i.e.,
bioavailability. Volume of distribution (A) is independent of first-pass effect. Half-life (C) depends on
clearance and volume of distribution, not directly on first-pass. Protein binding (D) is not altered by
first-pass metabolism.
8. A 60-year-old woman with type 2 diabetes mellitus and hypertension is started on lisinopril. Two
weeks later, she develops a dry cough. Which of the following mechanisms is most likely
responsible for this adverse effect?
A. Accumulation of bradykinin due to inhibition of ACE
B. Direct irritation of bronchial mucosa by the drug
C. Increased production of leukotrienes via COX inhibition
D. Stimulation of cough reflex by angiotensin II accumulation
Answer: A
Rationale: ACE inhibitors block the degradation of bradykinin, which accumulates and stimulates cough.
Option B is not a known mechanism. COX inhibition (C) is associated with NSAIDs, not ACE inhibitors.
Angiotensin II (D) is decreased by ACE inhibitors, not increased.
9. In a patient with ventricular tachycardia, administration of lidocaine is expected to exert its
antiarrhythmic effect primarily by which of the following mechanisms?
A. Blockade of beta-adrenergic receptors
B. Inhibition of slow calcium channels
C. Blockade of sodium channels with rapid offset kinetics
D. Prolongation of the cardiac action potential duration
Answer: C
Rationale: Lidocaine is a class IB antiarrhythmic that blocks sodium channels with fast dissociation
kinetics, preferentially affecting ischemic tissue. Beta-blockade (A) is class II. Calcium channel blockade
(B) is class IV. Prolongation of action potential (D) is class III (e.g., amiodarone).
10. Which of the following best describes the relationship between the pKa of a weak acid drug and
its absorption in the stomach (pH 1.5)?
A. Drugs with pKa less than 1.5 are predominantly ionized and poorly absorbed
B. Drugs with pKa greater than 1.5 are predominantly unionized and well absorbed
C. Absorption is independent of pKa because stomach pH is constant
D. Drugs with pKa equal to 7.4 are optimally absorbed in the stomach
Answer: B
Page 3
, Rationale: For a weak acid, the unionized form is lipid-soluble and absorbed. Using the Henderson-Hasselbalch equation,
when pH < pKa, the unionized form predominates. Thus, weak acids with pKa > stomach pH are mostly unionized and well
absorbed. Option A is incorrect because pKa < 1.5 would mean the drug is mostly unionized. Option C ignores the
pH-partition hypothesis. Option D is optimal for small intestine, not stomach.
11. In a study of a novel kinase inhibitor, the drug shows a 50% reduction in tumor growth in
xenograft models at a plasma concentration of 2 µM. However, in vitro assays reveal an IC50 of 0.5
µM against the target kinase. Which pharmacokinetic parameter best explains the discrepancy
between in vitro potency and in vivo efficacy?
A. Volume of distribution
B. Protein binding
C. Bioavailability
D. Half-life
Answer: B
Rationale: High protein binding reduces the free drug concentration available to interact with the target,
shifting the in vivo concentration needed for effect. Volume of distribution affects distribution but not the
free fraction. Bioavailability and half-life influence overall exposure but not the direct relationship
between total plasma concentration and target engagement.
12. A 45-year-old individual presents with recurrent episodes of severe abdominal pain,
arthralgias, and a purpuric rash on the lower extremities. Laboratory findings show elevated
serum IgA levels and normal platelet count. Biopsy of the rash reveals leukocytoclastic vasculitis
with IgA deposition. Which of the following pathophysiologic mechanisms is most directly
responsible for the vascular damage in this condition?
A. Type II hypersensitivity reaction with antibody-dependent cell-mediated cytotoxicity
B. Immune complex deposition triggering complement activation and neutrophil recruitment
C. Direct T-cell mediated cytotoxicity against endothelial cells
D. IgE-mediated mast cell degranulation leading to vasodilation and edema
Answer: B
Rationale: IgA vasculitis (Henoch-Schönlein purpura) involves deposition of IgA-containing immune
complexes in small vessels, activating complement and attracting neutrophils, which release enzymes
causing vessel damage. Type II hypersensitivity targets specific cells, not immune complexes. T-cell
mediated and IgE mechanisms are not primary in this disorder.
13. A researcher is investigating a signaling pathway where a ligand binds to a receptor tyrosine
kinase (RTK), leading to activation of Ras and downstream MAPK cascade. They introduce a
mutation that prevents the RTK from internalizing after ligand binding. Which of the following is
the most likely consequence for signal transduction?
A. Decreased amplitude of the initial signal due to prolonged receptor activation
B. Sustained signaling with potential for oncogenic transformation
C. Complete loss of signal because internalization is required for Ras activation
D. No effect, as internalization only terminates signaling
Page 4
Actual Questions & Verified Answers, Plus Explained
Rationales/Expert Verified For Guaranteed 100%
Pass 2026/Latest Update/Instant Download Pdf
1. In the context of osteopathic manipulative treatment (OMT), which of the following best
describes the mechanism by which myofascial release improves somatic dysfunction?
A. Inhibition of nociceptive afferents via descending pain modulatory pathways
B. Stretching of shortened fascia to restore tissue fluid dynamics and reduce sympathetic tone
C. Activation of Golgi tendon organs leading to autogenic inhibition of muscle spindles
D. Direct mechanical realignment of vertebral segments through high-velocity thrust
Answer: B
Rationale: Myofascial release targets fascial restrictions; stretching the fascia improves fluid flow and
reduces sympathetic nervous system hyperactivity. Option A describes counterstimulation or
acupuncture-like effects, not myofascial release. Option C is the mechanism for muscle energy
technique. Option D describes high-velocity low-amplitude (HVLA) thrust.
2. A researcher isolates a novel Gram-negative bacterium from a patient with ventilator-associated
pneumonia. The organism produces a beta-lactamase that hydrolyzes ceftazidime but not cefepime.
Which of the following mechanisms is most likely responsible?
A. ESBL (Extended-Spectrum Beta-Lactamase) production
B. AmpC beta-lactamase hyperproduction
C. KPC (Klebsiella pneumoniae carbapenemase) production
D. OXA-48-type carbapenemase
Answer: B
Rationale: AmpC beta-lactamases hydrolyze cephalosporins like ceftazidime but are less active against
cefepime. ESBLs (A) are inhibited by clavulanate and typically hydrolyze cefepime. KPC (C) and
OXA-48 (D) are carbapenemases that hydrolyze carbapenems, not just ceftazidime.
3. In a patient with chronic obstructive pulmonary disease (COPD) and cor pulmonale, which of
the following hemodynamic changes is most likely to be observed on right heart catheterization?
A. Decreased pulmonary capillary wedge pressure and increased cardiac output
B. Increased pulmonary artery pressure and decreased right ventricular ejection fraction
C. Decreased right atrial pressure and increased pulmonary vascular resistance
D. Increased left ventricular end-diastolic pressure and decreased systemic vascular resistance
Answer: B
Rationale: Cor pulmonale results from pulmonary hypertension, causing increased pulmonary artery
pressure and reduced right ventricular function. Wedge pressure (A) is normal in cor pulmonale (no left
Page 1
,heart disease). Right atrial pressure is increased, not decreased (C). Left-sided pressures (D) are normal
unless concomitant left heart disease exists.
4. A 30-year-old individual with a history of recurrent sinopulmonary infections and
bronchiectasis is found to have situs inversus totalis. Which of the following cellular defects is most
likely responsible for this condition?
A. Defective chloride transport due to CFTR mutation
B. Impaired ciliary motility due to dynein arm deficiency
C. Abnormal surfactant production due to SP-B deficiency
D. Deficiency of alpha-1 antitrypsin leading to protease imbalance
Answer: B
Rationale: The combination of situs inversus, bronchiectasis, and sinusitis is characteristic of primary
ciliary dyskinesia (Kartagener's syndrome), caused by defective dynein arms impairing ciliary motility.
CFTR mutation (A) causes cystic fibrosis but not situs inversus. Surfactant deficiency (C) causes
neonatal respiratory distress. Alpha-1 antitrypsin deficiency (D) causes emphysema and liver disease.
5. Which of the following best explains why a patient with chronic kidney disease (CKD) stage 4
develops hyperphosphatemia despite a normal dietary phosphate intake?
A. Increased renal tubular reabsorption of phosphate due to elevated 1,25-dihydroxyvitamin D
B. Decreased glomerular filtration of phosphate leading to reduced phosphate excretion
C. Increased bone resorption of phosphate secondary to secondary hyperparathyroidism
D. Decreased intestinal phosphate binding due to reduced gastric acid secretion
Answer: B
Rationale: In advanced CKD, reduced nephron mass decreases phosphate filtration, causing retention.
Option A is incorrect because 1,25-vitamin D is low in CKD, not high. Option C contributes but is
secondary; the primary defect is renal excretion. Option D is not a major factor; intestinal absorption is
normal.
6. A 45-year-old man presents with acute onset of severe epigastric pain radiating to the back,
nausea, and vomiting. Serum lipase is elevated. Which of the following laboratory findings would
most strongly suggest a biliary etiology?
A. Elevated serum amylase with normal lipase
B. Elevated alanine aminotransferase (ALT) greater than 3 times the upper limit of normal
C. Elevated direct bilirubin with normal alkaline phosphatase
D. Elevated serum triglycerides (1500 mg/dL)
Answer: B
Rationale: In gallstone pancreatitis, transient elevation of ALT >3x normal is common due to passage of
a stone through the ampulla. Amylase and lipase are both elevated, not just amylase (A). Direct bilirubin
may be elevated but alkaline phosphatase is also typically elevated (C). Hypertriglyceridemia (D) is an
etiology itself but not a marker of biliary origin.
Page 2
,7. Which of the following pharmacokinetic changes is most characteristic of drugs that undergo
extensive first-pass metabolism when administered orally?
A. Increased volume of distribution
B. Reduced bioavailability
C. Prolonged elimination half-life
D. Decreased protein binding
Answer: B
Rationale: First-pass metabolism reduces the fraction of an oral dose reaching systemic circulation, i.e.,
bioavailability. Volume of distribution (A) is independent of first-pass effect. Half-life (C) depends on
clearance and volume of distribution, not directly on first-pass. Protein binding (D) is not altered by
first-pass metabolism.
8. A 60-year-old woman with type 2 diabetes mellitus and hypertension is started on lisinopril. Two
weeks later, she develops a dry cough. Which of the following mechanisms is most likely
responsible for this adverse effect?
A. Accumulation of bradykinin due to inhibition of ACE
B. Direct irritation of bronchial mucosa by the drug
C. Increased production of leukotrienes via COX inhibition
D. Stimulation of cough reflex by angiotensin II accumulation
Answer: A
Rationale: ACE inhibitors block the degradation of bradykinin, which accumulates and stimulates cough.
Option B is not a known mechanism. COX inhibition (C) is associated with NSAIDs, not ACE inhibitors.
Angiotensin II (D) is decreased by ACE inhibitors, not increased.
9. In a patient with ventricular tachycardia, administration of lidocaine is expected to exert its
antiarrhythmic effect primarily by which of the following mechanisms?
A. Blockade of beta-adrenergic receptors
B. Inhibition of slow calcium channels
C. Blockade of sodium channels with rapid offset kinetics
D. Prolongation of the cardiac action potential duration
Answer: C
Rationale: Lidocaine is a class IB antiarrhythmic that blocks sodium channels with fast dissociation
kinetics, preferentially affecting ischemic tissue. Beta-blockade (A) is class II. Calcium channel blockade
(B) is class IV. Prolongation of action potential (D) is class III (e.g., amiodarone).
10. Which of the following best describes the relationship between the pKa of a weak acid drug and
its absorption in the stomach (pH 1.5)?
A. Drugs with pKa less than 1.5 are predominantly ionized and poorly absorbed
B. Drugs with pKa greater than 1.5 are predominantly unionized and well absorbed
C. Absorption is independent of pKa because stomach pH is constant
D. Drugs with pKa equal to 7.4 are optimally absorbed in the stomach
Answer: B
Page 3
, Rationale: For a weak acid, the unionized form is lipid-soluble and absorbed. Using the Henderson-Hasselbalch equation,
when pH < pKa, the unionized form predominates. Thus, weak acids with pKa > stomach pH are mostly unionized and well
absorbed. Option A is incorrect because pKa < 1.5 would mean the drug is mostly unionized. Option C ignores the
pH-partition hypothesis. Option D is optimal for small intestine, not stomach.
11. In a study of a novel kinase inhibitor, the drug shows a 50% reduction in tumor growth in
xenograft models at a plasma concentration of 2 µM. However, in vitro assays reveal an IC50 of 0.5
µM against the target kinase. Which pharmacokinetic parameter best explains the discrepancy
between in vitro potency and in vivo efficacy?
A. Volume of distribution
B. Protein binding
C. Bioavailability
D. Half-life
Answer: B
Rationale: High protein binding reduces the free drug concentration available to interact with the target,
shifting the in vivo concentration needed for effect. Volume of distribution affects distribution but not the
free fraction. Bioavailability and half-life influence overall exposure but not the direct relationship
between total plasma concentration and target engagement.
12. A 45-year-old individual presents with recurrent episodes of severe abdominal pain,
arthralgias, and a purpuric rash on the lower extremities. Laboratory findings show elevated
serum IgA levels and normal platelet count. Biopsy of the rash reveals leukocytoclastic vasculitis
with IgA deposition. Which of the following pathophysiologic mechanisms is most directly
responsible for the vascular damage in this condition?
A. Type II hypersensitivity reaction with antibody-dependent cell-mediated cytotoxicity
B. Immune complex deposition triggering complement activation and neutrophil recruitment
C. Direct T-cell mediated cytotoxicity against endothelial cells
D. IgE-mediated mast cell degranulation leading to vasodilation and edema
Answer: B
Rationale: IgA vasculitis (Henoch-Schönlein purpura) involves deposition of IgA-containing immune
complexes in small vessels, activating complement and attracting neutrophils, which release enzymes
causing vessel damage. Type II hypersensitivity targets specific cells, not immune complexes. T-cell
mediated and IgE mechanisms are not primary in this disorder.
13. A researcher is investigating a signaling pathway where a ligand binds to a receptor tyrosine
kinase (RTK), leading to activation of Ras and downstream MAPK cascade. They introduce a
mutation that prevents the RTK from internalizing after ligand binding. Which of the following is
the most likely consequence for signal transduction?
A. Decreased amplitude of the initial signal due to prolonged receptor activation
B. Sustained signaling with potential for oncogenic transformation
C. Complete loss of signal because internalization is required for Ras activation
D. No effect, as internalization only terminates signaling
Page 4
