Pharmacology USMLE step 1 Exam NEW UPDATE 2023 WITH QUESTIONS AND CORRECT ANSWERS |GRADED A

Pharmacology USMLE step 1 Exam NEW UPDATE 2023 WITH QUESTIONS AND CORRECT ANSWERS |GRADED A What are the major functions of the α1 receptor? - 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? - 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? - ANSWER- Increase heart rate, increase contractility, increase renin release, increase lipolysis What are the major functions of the β2 receptor? - 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? - ANSWER- CNS, enteric nervous system What are the major functions of the M2 receptor? - ANSWER- Decrease heart rate and contractility of atria What are the major functions of the M3 receptor? - 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? - ANSWER- Relaxes renal vascular smooth muscle What are the major functions of the D2 receptor? - ANSWER- Modulates transmitter release, especially in the brain What are the major functions of the H1 receptor? - ANSWER- Increase nasal and bronchial mucus production, increase vascular permeability, contraction of bronchioles, pruritis, pain What are the major functions of the H2 receptor? - ANSWER- Increase gastric acid secretion What are the major functions of the V1 receptor? - ANSWER- Increase vascular smooth muscle contraction What are the major functions of the V2 receptor? - ANSWER- Increase H2O permeability and reabsorption in collecting tubules of kidney (V2 is found in the "2" kidneys) What receptors are associate with Gq? - ANSWER- H1, α1, V1, M1, and M3 What receptors are associated with Gs? - ANSWER- H2, B1, B2, V2, D1 What receptors are associated with Gi? - ANSWER- M2, α2, D2 Bethanechol - ANSWER- -Direct cholinergic agonist -Activates bowel and bladder smooth muscle -Used in postoperative and neurogenic ileus -Resistant to AChE Carbachol - ANSWER- -Direct cholinergic agonist -Carbon copy of acetylcholine -Constricts pupils and relieves intraocular pressure in glaucoma Methacholine - ANSWER- -Direct cholinergic agonist -Stimulates muscarinic receptors in airways when inhaled -Used as a challenge test for diagnosis of asthma Pilocarpine - 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 - ANSWER- -Anticholinesterse - increases ACh -Alzheimer disease Galantamine - ANSWER- -Anticholinesterse - increases ACh -Alzheimer disease Rivastigmine - ANSWER- -Anticholinesterse - increases ACh -Alzheimer disease Edrophonium - ANSWER- -Anticholinesterse - increases ACh -Historically used to diagnose myasthenia gravis (MG is now diagnosed by anti-AChR Ab test. Neostigmine - ANSWER- -Anticholinesterse - increases ACh -Used in postoperative and neurogenic ileus and urinary retention, myasthenia gravis, and postoperative reversal of neuromuscular junction blockade Physostigmine - ANSWER- -Anticholinesterse - increases ACh -Used in anticholinergic toxicity -Crosses the blood-brain barrier (CNS) Pyridostigmine - ANSWER- -Anticholinesterse - increases ACh -Increases muscle strength -Used in myasthenia gravis (long acting) -Does not penetrate CNS Atropine - 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 - ANSWER- -Muscarinic antagonist -Works in CNS -Used in Parkinson disease and acute dystonia Glycopyrrolate - ANSWER- -Muscarinic antagonist -Parental use: preoperative use to reduce airway secretions -Oral use: drooling, peptic ulcer Hyoscyamine - ANSWER- -Muscarinic antagonist -Antispasmodics for IBS Dicyclomide - ANSWER- -Muscarinic antagonist -Antispasmodics for IBS Ipratropium - ANSWER- -Muscarinic antagonist -Used in COPD and asthma Tiotropium - ANSWER- -Muscarinic antagonist -Used in COPD and asthma Oxybutynin - ANSWER- -Muscarinic antagonist -Reduced bladder spasms and urge urinary incontinence Solifenacin - ANSWER- -Muscarinic antagonist -Reduced bladder spasms and urge urinary incontinence Tolterodine - ANSWER- -Muscarinic antagonist -Reduced bladder spasms and urge urinary incontinence Scopalamine - ANSWER- -Muscarinic antagonist -Motion sickness Tetrodotoxin - 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 - 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 - 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).