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USMLE Step 1 Pharmacology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Explain potency in relation to full and partial agonists(2).
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

2. What drug is used during the pregnancy of an HIV+ mother? - Why?
Verapamil - Diltiazem - Bepridil
AZT - to reduce risk of Fetal Transmission
Inhibits cell wall mucopeptide formation - Bactericidal
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)

3. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Neutropenia
new arrhythmias - hypotension
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.

4. How is Trimethoprim used clinically?
Used in combination therapy with SMZ to sequentially block folate synthesis
Prevents the release of Ca from SR of skeletal muscle
Lipoxygenase
Suramin

5. What is the MOA for Trimethoprim (TMP)?
Phenothiazine (neuroleptic - antiemetic).
Foscarnet = pyroFosphate analog
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

6. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
- Nitrate - hydroxocobalamin thiosulfate
Local anesthetic.
Hydralazine and Minoxidil
Large anionic polymer - acidic

7. Acetazolamide - mechanism?
- Phenytoin
fetal renal toxicity - hyperkalemia
Reversible block of histamine H2 receptors
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

8. List the specific antidote for this toxin: Amphetamine
Rifampin
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
cholestyramine - colestipol
- Ammonium Chloride

9. What are the side effects of Rifampin?
Minor hepatotoxicity - Drug interactions (activates P450)
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Does not cross
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

10. What is the effect of norepinephrine on bp and pulse pressure?
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
No - warfarin - unlike heparin - can cross the placenta.

11. What is Metronidazole combined with for 'triple therapy'? Against What organism?
Sildenafil fills the penis
Neomycin
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Hypersensitivity reactions

12. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
ACE inhibitor.
Hypersensitivity reactions
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

13. What are the four conditions in Which Omeprazole - Lansoprazole is used?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Beta - lactamase cleavage of Beta - lactam ring
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia

14. Which cancer drugs work at the level of proteins(2)?
No - it inhibits the release of Nor Epi
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Erectile dysfunction.
- Vinca alkaloids(inhibit MT) - Paclitaxel

15. Which drug(s) cause this reaction: Tardive dyskinesia?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
- Tricyclic antidepressants
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- Antipsychotics

16. Ca2+ sensitizers'- site of action?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Diarrhea
GI side effects. (Indomethacin is less toxic - more commonly used.)
troponin - tropomyosin system

17. Acetazolamide - clinical uses?
Disulfiram - like reaction with EtOH - Headache
Benzodiazepine.
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
It affects beta receptors equally and is used in AV heart block (rare).

18. What neurotransmitter does Amantadine affect? How does it influence this NT?
Dopamine; causes its release from intact nerve terminals
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Ceftriaxone
- Phenytoin

19. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Same as penicillin. Extended spectrum antibiotics
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
Those patients who are taking nitrates.
Polymyxin B - Polymyxin E

20. What is the specific clinical use of Indomethacin in neonates?
Early myocardial infarction.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Indomethacin is used to close a patent ductus arteriosus.
block Na+ channels in the cortical collecting tubule

21. What is the clinical use of Mifepristone (RU486)?
Abortifacient.
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Beta - lactamase cleavage of Beta - lactam ring
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

22. MOA: Block mRNA synthesis
Paranteral (IV - SC)
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Rifampin
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

23. What is the category of drug names ending in - ane (e.g. Halothane)
Diuresis in pateints with sulfa allergy
1. Antiandrogen 2. Nausea 3. Vomiting
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Inhalational general anesthetic.

24. List the specific antidote for this toxin: Acetaminophen
- Vinca alkaloids(inhibit MT) - Paclitaxel
all of them
for RSV
- N- acetylcystine

25. What are the clinical uses for Ticlopidine - Clopidogrel?
thiazides - amiloride
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium

26. For Heparin What is the Mechanism of action
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
severe hypertension - CHF
Activates antithrombin III
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

27. ACE inhibitors - clinical use?
- Tetracycline - amiodarone - sulfonamides
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Phenothiazine (neuroleptic - antiemetic).
hypertension - CHF - diabetic renal disease

28. What is the major side effect for Ampicillin and Amoxicillin?
Hypersensitivity reactions
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Reversible block of histamine H2 receptors

29. What is the memory key for the action of Sildenafil (Viagra)?
No
Sildenafil fills the penis
- Niacin - Ca++ channel blockers - adenosine - vancomycin
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

30. What are two Glitazones?
- NaHCO3
1. Pioglitazone 2. Rosiglitazone.
- Alkalate DNA - Brain tumors - CNS toxicity
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

31. Which RT inhibitors cause a Rash?
Non - Nucleosides
- Fluoroquinolones
check PFTs - LFTs - and TFTs
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

32. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
cholestyramine - colestipol
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.
Protease Inhibitors and Reverse Transcriptase Inhibitors
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

33. Which diuretics cause acidosis?
carbonic anhydrase inhibitors - K+ sparing diuretics
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Intrathecally

34. What are common side effects of Amphotericin B?
Decreased uptake or Increased transport out of cell
Pituitary hormone.
Constant FRACTION eliminated per unit time.(exponential)
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

35. Aztreonam is not ________ with penicillins
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
cross - allergenic
INH: Injures Neurons and Hepatocytes
- Quinidine - quinine

36. What are signs of Sildenafil (Viagra) toxicity?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Headache - flushing - dyspepsia - blue - green color vision.

37. Resistance mechanisms for Macrolides

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38. What enzyme is responsible for the degredation of Ach
- Glucocorticoid withdrawal
Acetylcholine esterase
Short.
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

39. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
Staphlococcus aureus
- Oral Contraceptives
Binds to the Pyrophosphate Binding Site of the enzyme
- Disulfram & also sulfonylureas - metronidazole

40. How do you calculate maintenance dose?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Acute (hours)
Methicillin - Nafcillin - and Dicloxacillin
- Chloramphenicol

41. What are Fluoroquinolones indicated for? (3)
Tricyclic antidepressant.
Primaquine
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

42. What is the category of drug names ending in - caine (e.g. Lidocaine)
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Local anesthetic.
Beta adrenergic receptors and Ca2+ channels (stimulatory)
- Oral Contraceptives

43. What is the mechanism of action of the Sulfonylureas?
G6PD deficient individuals
Chronic gout.
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Hemolytic anemia

44. For Warfarin What is the Mechanism of action
Rapid (seconds)
GI side effects. (Indomethacin is less toxic - more commonly used.)
Protease inhibitor.
Impairs the synthesis of vitamin K- dependent clotting factors

45. Foscarnet toxicity?
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
Sotalol - Ibutilide - Bretylium - Amiodarone
Nephrotoxicity
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

46. What process does Zafirlukast interfere with?
Leukotrienes increasing bronchial tone.
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Cell membrane Ca2+ channels of cardiac sarcomere

47. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Methylxanthine.
- Bleomycin - amiodarone - busulfan

48. Acetazolamide causes?

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49. Digoxin v. Digitoxin: excretion?
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Digoxin=urinary Digitoxin=biliary
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
proximal convoluted tubule

50. What is the formula for Volume of distribution (Vd)
- Ammonium Chloride
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Vd= (Amt. of drug in body/ Plasma drug conc.)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis