Pharmacology USMLE Step 1 Exam 2025
– 350 Complete Questions with 100%
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What are the major functions of the α1 receptor? - CORRECT ANSWER>>>>Increase
vascular smooth muscle contraction, increase pupillary dilator muscle contraction (mydriasis),
increase intestinal and bladder sphincter muscle contraction
What are the major functions of the α2 receptor? - CORRECT ANSWER>>>>Decrease
sympathetic outflow, decrease insulin release, decrease lipolysis, increase platelet
aggregation, decrease aqueous humor production
What are the major functions of the β1 receptor? - CORRECT ANSWER>>>>Increase
heart rate, increase contractility, increase renin release, increase lipolysis
What are the major functions of the β2 receptor? - CORRECT ANSWER>>>>Vasodilation,
bronchodilation, increase lipolysis, increase insulin release, decrease uterine tone
(tocolysis), ciliary muscle relaxation, increase aqueous humor production
What are the major functions of the M1 receptor? - CORRECT ANSWER>>>>CNS,
enteric nervous system
What are the major functions of the M2 receptor? - CORRECT ANSWER>>>>Decrease
heart rate and contractility of atria
What are the major functions of the M3 receptor? - CORRECT ANSWER>>>>Increase
exocrine gland secretions (e.g., lacrimal, salivary, gastric acid), increase gut peristalsis,
increase bladder contraction, increase bronchoconstriction, pupillary sphincter muscle
contraction (miosis), ciliary muscle contraction (accommodation)
What are the major functions of the D1 receptor? - CORRECT ANSWER>>>>Relaxes
renal vascular smooth muscle
What are the major functions of the D2 receptor? - CORRECT
ANSWER>>>>Modulates transmitter release, especially in the brain
,What are the major functions of the H1 receptor? - CORRECT ANSWER>>>>Increase
nasal and bronchial mucus production, increase vascular permeability, contraction of
bronchioles, pruritis, pain
What are the major functions of the H2 receptor? - CORRECT ANSWER>>>>Increase
gastric acid secretion
What are the major functions of the V1 receptor? - CORRECT ANSWER>>>>Increase
vascular smooth muscle contraction
What are the major functions of the V2 receptor? - CORRECT ANSWER>>>>Increase H2O
permeability and reabsorption in collecting tubules of kidney (V2 is found in the "2" kidneys)
What receptors are associate with Gq? - CORRECT ANSWER>>>>H1, α1, V1, M1, and M3
What receptors are associated with Gs? - CORRECT ANSWER>>>>H2, B1, B2, V2, D1
What receptors are associated with Gi? - CORRECT ANSWER>>>>M2, α2, D2
Bethanechol - CORRECT ANSWER>>>>-Direct cholinergic
agonist -Activates bowel and bladder smooth muscle -Used in
postoperative and neurogenic ileus
-Resistant to AChE
Carbachol - CORRECT ANSWER>>>>-Direct cholinergic
agonist -Carbon copy of acetylcholine
-Constricts pupils and relieves intraocular pressure in glaucoma
Methacholine - CORRECT ANSWER>>>>-Direct cholinergic
agonist -Stimulates muscarinic receptors in airways when inhaled -
Used as a challenge test for diagnosis of asthma
Pilocarpine - CORRECT ANSWER>>>>-Direct cholinergic agonist
-Contracts ciliary muscle of eye (open angle glaucoma), contracts pupillary sphincter
(closed angle glaucoma)
-Potent stimulator of sweat, tears and saliva
-AChE resistant
Donepezil - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Alzheimer disease
Galantamine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Alzheimer disease
Rivastigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Alzheimer disease
,Edrophonium - CORRECT ANSWER>>>>-Anticholinesterse - increases ACh
-Historically used to diagnose myasthenia gravis (MG is now diagnosed by anti-AChR Ab test.
Neostigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases ACh
-Used in postoperative and neurogenic ileus and urinary retention, myasthenia gravis,
and postoperative reversal of neuromuscular junction blockade
Physostigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Used in anticholinergic toxicity
-Crosses the blood-brain barrier (CNS)
Pyridostigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Increases muscle strength
-Used in myasthenia gravis (long acting)
-Does not penetrate CNS
Atropine - CORRECT ANSWER>>>>-Muscarinic antagonist -
Used in bradycardia and for ophthalmic applications
-Also used as antidote for cholinesterase inhibitor poisoning
-Actions include increase pupil dilation, cycloplegia, decreased airway secretions, decreased
acid secretions, decreased gut motility, decreased bladder urgency in cystitis
-Toxicity: increased body temp (due to decreased sweating), rapid pulse, dry mouth, dry
and flushed skin, cycloplegia, constipation, disorientation;
-Can cause acute angle-closure glaucoma in elderly (due to mydriasis), urinary retention in
men with prostatic hyperplasia, and hyperthermia in infants -See also homatropine and
tropicamide
Benztropine - CORRECT ANSWER>>>>-Muscarinic
antagonist -Works in CNS
-Used in Parkinson disease and acute dystonia
Glycopyrrolate - CORRECT ANSWER>>>>-Muscarinic
antagonist -Parental use: preoperative use to reduce airway
secretions -Oral use: drooling, peptic ulcer
Hyoscyamine - CORRECT ANSWER>>>>-Muscarinic
antagonist -Antispasmodics for IBS
Dicyclomide - CORRECT ANSWER>>>>-Muscarinic
antagonist -Antispasmodics for IBS
Ipratropium - CORRECT ANSWER>>>>-Muscarinic
antagonist -Used in COPD and asthma
Tiotropium - CORRECT ANSWER>>>>-Muscarinic antagonist
, -Used in COPD and asthma
Oxybutynin - CORRECT ANSWER>>>>-Muscarinic antagonist -
Reduced bladder spasms and urge urinary incontinence
Solifenacin - CORRECT ANSWER>>>>-Muscarinic antagonist -
Reduced bladder spasms and urge urinary incontinence
Tolterodine - CORRECT ANSWER>>>>-Muscarinic antagonist -
Reduced bladder spasms and urge urinary incontinence
Scopalamine - CORRECT ANSWER>>>>-Muscarinic
antagonist -Motion sickness
Tetrodotoxin - CORRECT ANSWER>>>>-Poisoning can result from ingestion of poorly
prepared puffer fish (exotic sushi)
-Highly potent toxin that binds fast voltage-gated Na+ channels in cardiac and nerve tissue,
preventing depolarization - blocks action potential without changing resting potential (same
mechanism as Lidocaine)
-Causes nausea, diarrhea, paresthesias, weakness, dizziness, loss of reflexes.
-Treatment is primarily supportive.
Ciguatoxin - CORRECT ANSWER>>>>-Consumption of reef fish (e.g. barracuda,
snapper, eel...)
-Causes ciguatera fish poisoning.
-Opens Na+ channels causing depolarization. Symptoms easily confused with
cholinergic poisoning.
-Temperature-related dysesthesia (e.g., "cold feels hot; hot feels cold") is regarded as a
specific finding of ciguatera.
-Treatment is primarily supportive.
Scombroid poisoning - CORRECT ANSWER>>>>-Caused by consumption of dark-meat
fish (e.g., bonito, mackerel, mahi-mahi, tuna) improperly stored at warm temperature.
-Bacterial histidine decarboxylase converts histidine to histamine. Histamine is not degraded
by cooking.
-Acute-onset burning sensation of the mouth, flushing of face, erythema, urticaria,
pruritus, headache. May cause anaphylaxis-like presentation (i.e., bronchospasm,
angioedema, hypotension).
-Frequently misdiagnosed as allergy to fish.
-Treat supportively with antihistamines; if needed, antianaphylactics (e.g.,
bronchodilators, epinephrine).
Albuterol - CORRECT ANSWER>>>>-β2 > β1 direct
agonist -Acute asthma
Salmterol - CORRECT ANSWER>>>>-β2 > β1 direct agonist
– 350 Complete Questions with 100%
Correct Verified Answers | Expert
Verified, Already Graded A+, Brand-New
Update
What are the major functions of the α1 receptor? - CORRECT ANSWER>>>>Increase
vascular smooth muscle contraction, increase pupillary dilator muscle contraction (mydriasis),
increase intestinal and bladder sphincter muscle contraction
What are the major functions of the α2 receptor? - CORRECT ANSWER>>>>Decrease
sympathetic outflow, decrease insulin release, decrease lipolysis, increase platelet
aggregation, decrease aqueous humor production
What are the major functions of the β1 receptor? - CORRECT ANSWER>>>>Increase
heart rate, increase contractility, increase renin release, increase lipolysis
What are the major functions of the β2 receptor? - CORRECT ANSWER>>>>Vasodilation,
bronchodilation, increase lipolysis, increase insulin release, decrease uterine tone
(tocolysis), ciliary muscle relaxation, increase aqueous humor production
What are the major functions of the M1 receptor? - CORRECT ANSWER>>>>CNS,
enteric nervous system
What are the major functions of the M2 receptor? - CORRECT ANSWER>>>>Decrease
heart rate and contractility of atria
What are the major functions of the M3 receptor? - CORRECT ANSWER>>>>Increase
exocrine gland secretions (e.g., lacrimal, salivary, gastric acid), increase gut peristalsis,
increase bladder contraction, increase bronchoconstriction, pupillary sphincter muscle
contraction (miosis), ciliary muscle contraction (accommodation)
What are the major functions of the D1 receptor? - CORRECT ANSWER>>>>Relaxes
renal vascular smooth muscle
What are the major functions of the D2 receptor? - CORRECT
ANSWER>>>>Modulates transmitter release, especially in the brain
,What are the major functions of the H1 receptor? - CORRECT ANSWER>>>>Increase
nasal and bronchial mucus production, increase vascular permeability, contraction of
bronchioles, pruritis, pain
What are the major functions of the H2 receptor? - CORRECT ANSWER>>>>Increase
gastric acid secretion
What are the major functions of the V1 receptor? - CORRECT ANSWER>>>>Increase
vascular smooth muscle contraction
What are the major functions of the V2 receptor? - CORRECT ANSWER>>>>Increase H2O
permeability and reabsorption in collecting tubules of kidney (V2 is found in the "2" kidneys)
What receptors are associate with Gq? - CORRECT ANSWER>>>>H1, α1, V1, M1, and M3
What receptors are associated with Gs? - CORRECT ANSWER>>>>H2, B1, B2, V2, D1
What receptors are associated with Gi? - CORRECT ANSWER>>>>M2, α2, D2
Bethanechol - CORRECT ANSWER>>>>-Direct cholinergic
agonist -Activates bowel and bladder smooth muscle -Used in
postoperative and neurogenic ileus
-Resistant to AChE
Carbachol - CORRECT ANSWER>>>>-Direct cholinergic
agonist -Carbon copy of acetylcholine
-Constricts pupils and relieves intraocular pressure in glaucoma
Methacholine - CORRECT ANSWER>>>>-Direct cholinergic
agonist -Stimulates muscarinic receptors in airways when inhaled -
Used as a challenge test for diagnosis of asthma
Pilocarpine - CORRECT ANSWER>>>>-Direct cholinergic agonist
-Contracts ciliary muscle of eye (open angle glaucoma), contracts pupillary sphincter
(closed angle glaucoma)
-Potent stimulator of sweat, tears and saliva
-AChE resistant
Donepezil - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Alzheimer disease
Galantamine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Alzheimer disease
Rivastigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Alzheimer disease
,Edrophonium - CORRECT ANSWER>>>>-Anticholinesterse - increases ACh
-Historically used to diagnose myasthenia gravis (MG is now diagnosed by anti-AChR Ab test.
Neostigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases ACh
-Used in postoperative and neurogenic ileus and urinary retention, myasthenia gravis,
and postoperative reversal of neuromuscular junction blockade
Physostigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Used in anticholinergic toxicity
-Crosses the blood-brain barrier (CNS)
Pyridostigmine - CORRECT ANSWER>>>>-Anticholinesterse - increases
ACh -Increases muscle strength
-Used in myasthenia gravis (long acting)
-Does not penetrate CNS
Atropine - CORRECT ANSWER>>>>-Muscarinic antagonist -
Used in bradycardia and for ophthalmic applications
-Also used as antidote for cholinesterase inhibitor poisoning
-Actions include increase pupil dilation, cycloplegia, decreased airway secretions, decreased
acid secretions, decreased gut motility, decreased bladder urgency in cystitis
-Toxicity: increased body temp (due to decreased sweating), rapid pulse, dry mouth, dry
and flushed skin, cycloplegia, constipation, disorientation;
-Can cause acute angle-closure glaucoma in elderly (due to mydriasis), urinary retention in
men with prostatic hyperplasia, and hyperthermia in infants -See also homatropine and
tropicamide
Benztropine - CORRECT ANSWER>>>>-Muscarinic
antagonist -Works in CNS
-Used in Parkinson disease and acute dystonia
Glycopyrrolate - CORRECT ANSWER>>>>-Muscarinic
antagonist -Parental use: preoperative use to reduce airway
secretions -Oral use: drooling, peptic ulcer
Hyoscyamine - CORRECT ANSWER>>>>-Muscarinic
antagonist -Antispasmodics for IBS
Dicyclomide - CORRECT ANSWER>>>>-Muscarinic
antagonist -Antispasmodics for IBS
Ipratropium - CORRECT ANSWER>>>>-Muscarinic
antagonist -Used in COPD and asthma
Tiotropium - CORRECT ANSWER>>>>-Muscarinic antagonist
, -Used in COPD and asthma
Oxybutynin - CORRECT ANSWER>>>>-Muscarinic antagonist -
Reduced bladder spasms and urge urinary incontinence
Solifenacin - CORRECT ANSWER>>>>-Muscarinic antagonist -
Reduced bladder spasms and urge urinary incontinence
Tolterodine - CORRECT ANSWER>>>>-Muscarinic antagonist -
Reduced bladder spasms and urge urinary incontinence
Scopalamine - CORRECT ANSWER>>>>-Muscarinic
antagonist -Motion sickness
Tetrodotoxin - CORRECT ANSWER>>>>-Poisoning can result from ingestion of poorly
prepared puffer fish (exotic sushi)
-Highly potent toxin that binds fast voltage-gated Na+ channels in cardiac and nerve tissue,
preventing depolarization - blocks action potential without changing resting potential (same
mechanism as Lidocaine)
-Causes nausea, diarrhea, paresthesias, weakness, dizziness, loss of reflexes.
-Treatment is primarily supportive.
Ciguatoxin - CORRECT ANSWER>>>>-Consumption of reef fish (e.g. barracuda,
snapper, eel...)
-Causes ciguatera fish poisoning.
-Opens Na+ channels causing depolarization. Symptoms easily confused with
cholinergic poisoning.
-Temperature-related dysesthesia (e.g., "cold feels hot; hot feels cold") is regarded as a
specific finding of ciguatera.
-Treatment is primarily supportive.
Scombroid poisoning - CORRECT ANSWER>>>>-Caused by consumption of dark-meat
fish (e.g., bonito, mackerel, mahi-mahi, tuna) improperly stored at warm temperature.
-Bacterial histidine decarboxylase converts histidine to histamine. Histamine is not degraded
by cooking.
-Acute-onset burning sensation of the mouth, flushing of face, erythema, urticaria,
pruritus, headache. May cause anaphylaxis-like presentation (i.e., bronchospasm,
angioedema, hypotension).
-Frequently misdiagnosed as allergy to fish.
-Treat supportively with antihistamines; if needed, antianaphylactics (e.g.,
bronchodilators, epinephrine).
Albuterol - CORRECT ANSWER>>>>-β2 > β1 direct
agonist -Acute asthma
Salmterol - CORRECT ANSWER>>>>-β2 > β1 direct agonist
