USMLE STEP 1 PHARMACOLOGY UPDATED QUESTIONS
AND ANSWERS
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
AND ANSWERS
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
