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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.
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1. What are the phases of succinylcholine neuromuscular blockade?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

2. Which drug(s) cause this reaction: Anaphylaxis?
- Penicillin
Hydralazine and Minoxidil
scopolamine
The only local anesthetic with vasoconstrictive properties.

3. What is a Ribavirin toxicity?
hyperaldosteronism - K+ depletion - CHF
Imipenem
Hemolytic anemia
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

4. List the mechanism - clinical use - & toxicity of Vincristine.

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5. What is treated with Chloroquine - Quinine - Mefloquine?
Malaria (P. falciparum)
Flecainide - Encainide - Propafenone
Staphlococcus aureus
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

6. What is the category of drug names ending in - azepam (e.g. Diazepam)
Acute gout.
- Penicillin
Benzodiazepine.
- Steroids - Tamoxifen

7. What is the category of drug names ending in - terol (e.g. Albuterol)
Acute (hours)
Beta -2 agonist.
Methylxanthine.
Same as penicillin. Act as narrow spectrum antibiotics

8. Foscarnet does not require activation by a...
- Flumazenil
new arrhythmias - hypotension
viral kinase
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

9. What is the MOA for the Cephalosporins?
TMP- SMZ
Quinidine - Amiodarone - Procainamide - Disopyramide
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Beta lactams - inhibit cell wall synthesis - Bactericidal

10. What are two toxicities of the Sulfonylureas?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
- Oxalic acid - Acidosis & nephrotoxicity
Megaloblastic anemia - Leukopenia - Granulocytopenia
Abortifacient.

11. Adenosine - clinical use?
Amphotericin B - Nystatin - Fluconazole/azoles
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
DOC in diagnosing and abolishing AV nodal arrhythmias
Indirect agonist - uptake inhibitor

12. Why is pyridostigmine effective in the treatment of myasthenia gravis?
Praziquantel
Slow - limited by half lives of clotting factors
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
As an anticholinesterase it increases endogenous ACh and thus increases strength.

13. For Warfarin What is the Mechanism of action
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Inhibition of 50S peptidyl transferase - Bacteriostatic
Polymyxins
Impairs the synthesis of vitamin K- dependent clotting factors

14. Adverse effects of ganglionic blockers?
fetal renal toxicity - hyperkalemia
Pituitary hormone.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
anuria - CHF

15. What is the memory key for Isoniazid (INH) toxicity?
Rash - Pseudomembranous colitis
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
INH: Injures Neurons and Hepatocytes
- N- acetylcystine

16. Why would dopamine be useful in treating shock?
Dopamine; causes its release from intact nerve terminals
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
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.
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

17. Resistance mechanisms for Macrolides

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18. What is the mechanism of action of Acetaminophen?
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Babiturate.
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Lovastatin - Pravastatin - Simvastatin - Atorvastatin

19. What are three possible complications of Heparin therapy?
Gram + - Gram - - Norcardia - Chlamydia
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Inhibit Ergosterol synthesis

20. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
1. Renal damage 2. Aplastic anemia 3. GI distress
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

21. What should not be taken with Tetracyclines? / Why?
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
troponin - tropomyosin system
Butyrophenone (neuroleptic).
Nevirapine - Delavirdine

22. What type of gout is treated with Allopurinol?
Chronic gout.
- Physostigmine salicylate
Pentamidine
With an amino acid change of D- ala D- ala to D- ala D- lac

23. For Heparin What is the Structure
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Large anionic polymer - acidic
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

24. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
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.
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

25. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Ibuprofen - Naproxen - and Indomethacin
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

26. Antiarrhythmic class II- toxicity?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Ataxia - Dizziness - Slurred speech

27. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
Slow - limited by half lives of clotting factors
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
- Chloramphenicol
Beta - lactam antibiotics

28. What is used to reverse the action of Heparin?
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Inhibition of 50S peptidyl transferase - Bacteriostatic
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).

29. What is the category of drug names ending in - ipramine (e.g. Imipramine)
- Vinca alkaloids(inhibit MT) - Paclitaxel
GI distress - Skin rash - and Seizures at high plasma levels
penicillinase resistant
Tricyclic antidepressant.

30. Common toxicities associated with Fluoroquinolones?
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Methylation of rRNA near Erythromycin's ribosome binding site

31. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
- Haloperidol - chlorpromazine - reserpine - MPTP
Norepinephrine
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.

32. What reversal agent could a Anes give to reverse the effects of Atropine
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
proarrhythmic
Interstitial nephritis
Bethanechol - Neostigmine - physostigmine

33. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
- Nitrate - hydroxocobalamin thiosulfate
Pretreat with antihistamines and a slow infusion rate
Choline acetyltransferase
Digoxin=urinary Digitoxin=biliary

34. For Heparin What is the Duration of action
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
is resistant
Increases coumadin metabolism
Acute (hours)

35. Which drug(s) cause this reaction: SLE- like syndrome?
Inhalational general anesthetic.
Verapamil - Diltiazem - Bepridil
- Hydralazine - Procainamide - INH - phenytoin
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

36. Adverse effects of Reserpine?
sedation - depression - nasal stuffiness - diarrhea
Captopril - Enalapril - Lisinopril
Only in limited amounts
Decreases synthesis of Mycolic Acid

37. MOA: Block protein synthesis at 30s subunit
- Cloazapine - carbamazapine - colchicine - PTU
Aminoglycosides - Tetracyclines
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
carbonic anhydrase inhibitors - K+ sparing diuretics

38. What is the MOA of Aztreonam?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
proximal convoluted tubule - thin descending limb - and collecting duct
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

39. Are Ampicillin and Amoxicillin are not...
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Choline acetyltransferase
penicillinase resistant
ACE inhibitor.

40. How is Chloramphenical used clinically?
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
decrease conduction velocity - increase ERP - increase PR interval
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

41. Which Aminoglycoside is used for Bowel Surgery ?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Neomycin
- Deferoxamine
Intrathecally

42. MOA: Block peptidoglycan synthesis
Erectile dysfunction.
Bacitracin - Vancomycin
- N- acetylcystine
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

43. Beta Blockers - BP?
decrease
Verapamil - Diltiazem - Bepridil
Stimulates beta adrenergic receptors
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

44. Name two organisms Vancomycin is commonly used for?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
distal convoluted tubule (early)
Activates antithrombin III

45. List the specific antidote for this toxin: Tricyclic antidepressants
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
- NaHCO3
reversible SLE- like syndrome
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.

46. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
- Formaldehyde & formic acid - severe acidosis & retinal damage
Digoxin=urinary Digitoxin=biliary
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Acetylcholinesterase; ACh is broken down into choline and acetate.

47. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
effective in torsade de pointes and digoxin toxicity
Because they require some residual islet function.
- Glucocorticoid withdrawal
Praziquantel

48. What is the mechanism of action of Heparin?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Heparin catalyzes the activation of antithrombin III.
AV nodal cells

49. Bretyllium - toxicity?
Blood
new arrhythmias - hypotension
amphetamine and ephedrine
Liver

50. Antiarrhythmic class IC- toxicity?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
proarrhythmic
Pseudomonas species and Gram - rods
Inhibits cell wall synthesis ( binds to PBP3). A monobactam