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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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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. Name common Polymyxins
Polymyxin B - Polymyxin E
Disulfiram - like reaction with EtOH - Headache
Tetracycline - Doxycycline - Demeclocycline - Minocycline
- Flumazenil

2. Why would dopamine be useful in treating shock?
- Chlorpromazine - thioridazine - haloperidol
Cardiac glycoside (inotropic agent).
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB

3. What anticholinesterase crosses the blood - brain - barrier?
physostigmine
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Chronic anticoagulation.
Give an antichloinesterase - neostigmine - edrophonium - etc

4. Ca2+ sensitizers'- site of action?
Pentamidine
The PTT.
troponin - tropomyosin system
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.)

5. What is Imipenem always administered with?
NO
Chronic gout.
Antileukotriene; blocks leukotriene receptors.
Cilastatin

6. Which diuretics decrease urine Ca2+?
Benzodiazepine.
- aminoglycosides - loop diuretics - cisplatin
thiazides - amiloride
YES

7. What is the clinical use for Heparin?
anticholinesterase glaucoma
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
-100% oxygen - hyperbaric
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

8. Common toxicities associated with Fluoroquinolones?
Clavulanic acid
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Yes - it does not cross the placenta.
DHPG (dihydroxy-2- propoxymethyl guanine)

9. Guanethidine enhances the release of Norepi?
Ca2+ (Loops Lose calcium)
No - it inhibits the release of Nor Epi
With an amino acid change of D- ala D- ala to D- ala D- lac
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time

10. Ethacrynic Acid - toxicity?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
These B-2 agonists cause respiratory smooth muscle to relax.
effective in torsade de pointes and digoxin toxicity
Digitoxin 168hrs Digoxin 40 hrs

11. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
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.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

12. Ganciclovir associated toxicities?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
- Alkalate DNA - Brain tumors - CNS toxicity
Heparin catalyzes the activation of antithrombin III.
Tetracycline - Doxycycline - Demeclocycline - Minocycline

13. List the mechanism - clinical use - & toxicity of 5 FU.
Sildenafil fills the penis
Abortifacient.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Gemfibrozil - Clofibrate

14. What is a possible toxicity of Ticlopidine - Clopidogrel usage?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Malaria (P. falciparum)
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Increase target cell response to insulin.

15. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
1. Reliable (<1% failure) 2. Lowers risk of endometrial and ovarian cancer 3. Decreased incidence of ectopic pregnancy 4. Lower risk of pelvic infections 5. Regulation of menses

16. What are toxic side effects for Metronidazole?
H2 antagonist
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Lidocaine - Mexiletine - Tocainide
Disulfiram - like reaction with EtOH - Headache

17. Verapamil has similar action to?
Beta Blockers
local anesthetic. CNS stimulation or depression. CV depression.
Pregnant women - Children; because animal studies show Damage to Cartilage
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

18. Acetazolamide - toxicity?
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Digoxin=urinary Digitoxin=biliary
Protease inhibitor.

19. Clinical use of Isoniazid (INH)?
Antileukotriene; blocks leukotriene receptors.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
prevention of nodal arrhythmias (SVT)
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB

20. What is the category of drug names ending in - azepam (e.g. Diazepam)
Benzodiazepine.
Early myocardial infarction.
TMP- SMZ (DOC) - aerosolized pentamidine
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

21. Antimicrobial prophylaxis for PCP
compensatory tachycardia - fluid retention - lupus - like syndrome
TMP- SMZ (DOC) - aerosolized pentamidine
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
- B51Naloxone / naltrexone (Narcan)

22. What drugs target anticholinesterase
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
- Methotrexate - 5 FU - 6 mercaptopurine

23. What are three unwanted effects of Mifepristone?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
dry mouth - sedation - severe rebound hypertension

24. Name some common Sulfonamides (4)
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

25. MOA: Block peptidoglycan synthesis
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Minor hepatotoxicity - Drug interactions (activates P450)
Bacitracin - Vancomycin
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

26. Which drug(s) cause this reaction: P450 inhibition(6)?
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Rare.
Binds to the Pyrophosphate Binding Site of the enzyme
all of them

27. Antiarrhythmic class IB- clinical uses?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
cholestyramine - colestipol
Inhibits reabsorption of uric acid.
post MI and digitalis induced arrhythmias

28. Antiarrhythmic class IV- primary site of action?
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
AV nodal cells
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

29. Which cancer drugs work at the level of mRNA(2)?
Gram + cocci - Gram - rods - and Anerobes
- Physostigmine salicylate
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
- Steroids - Tamoxifen

30. What are the major toxic side effects of the Cephalosporins?
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Scopolamine

31. How is Ribavirin used clinically?
- Oxalic acid - Acidosis & nephrotoxicity
for RSV
TMP- SMZ (DOC) - aerosolized pentamidine
Short.

32. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Bethanechol - Neostigmine - physostigmine
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.

33. Antiarrhythmic class II- effects?
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Captopril - Enalapril - Lisinopril
cardiac depression - peripheral edema - flushing - dizziness - constipation

34. List the mechanism - clinical use - & toxicity of Bleomycin.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Forms toxic metabolites in the bacterial cell - Bactericidal
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

35. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
DOC in diagnosing and abolishing AV nodal arrhythmias
Ganciclovir is more toxic to host enzymes
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

36. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
Modification via Acetylation - Adenylation - or Phosphorylation
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Pralidoxime regenerates active cholinesterase.

37. Spironolactone - mechanism?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Rapid (seconds)
Antifungal.
competitive inhibirot of aldosterone in the cortical collecting tubule

38. What are two toxicities of the Sulfonylureas?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
- Haloperidol - chlorpromazine - reserpine - MPTP
Staphlococcus aureus
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

39. Why is carbachol and pilocarpine useful in treatment of glaucoma?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

40. What are two toxicities associated with Cyclosporine?
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Polymyxin B - Polymyxin E
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules

41. Beta Blockers - BP?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Chronic gout.
decrease
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

42. What is a common drug interaction associated with Griseofulvin?
Hydralazine and Minoxidil
Increases coumadin metabolism
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Pyridoxine (B6) administration

43. Which of epi - norepi - or isoproterenol results in bradycardia?
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Interferes with microtubule function - disrupts mitosis - inhibits growth
Norepinephrine
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

44. What antimicrobial class is Aztreonam syngergestic with?
loop diuretics - spironolactone
Aminoglycosides
torsade de pointes - excessive Beta block
- Shifts the curve down - reduces Vmax

45. What are common toxicities associated with Macrolides? (4)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Antibiotic - protein synthesis inhibitor.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Penicillin.

46. What type of patient should not take Misoprostol and why?
- Isoniazid
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Indirect agonist - uptake inhibitor
Same as penicillin. Extended spectrum antibiotics

47. IV Penicillin
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Penicillin - G
The PT.
With an amino acid change of D- ala D- ala to D- ala D- lac

48. Antimicrobial prophylaxis for Meningococcal infection
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Minor hepatotoxicity - Drug interactions (activates P450)
Rifampin (DOC) - minocycline

49. Hydralazine - toxicity?
GI discomfort
compensatory tachycardia - fluid retention - lupus - like syndrome
Non - Nucleosides
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers

50. How do the Protease Inhibitors work?
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Inhibt Assembly of new virus by Blocking Protease Enzyme
Pituitary hormone.
first dose orthostatic hypotension - dizziness - headache