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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. What are the clinical indications for Azole therapy?
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Dopamine; causes its release from intact nerve terminals
Systemic mycoses
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

2. Adverse effects of ganglionic blockers?
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
- Methylene blue

3. How does a competitive antagonist effect an agonist?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Choline acetyltransferase
dry mouth - sedation - severe rebound hypertension
- Shifts the curve to the right - increases Km

4. What are two clinical uses of Azathioprine?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
thiazides - amiloride
Antileukotriene; blocks leukotriene receptors.

5. How can the toxic effects of TMP be ameliorated?
With supplemental Folic Acid
Those patients who are taking nitrates.
Resistant Gram - infections
Minor hepatotoxicity - Drug interactions (activates P450)

6. What are four clinical uses of glucocorticoids?

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7. What type of gout is treated with Colchicine?
Benzathine penicillin G
hyperaldosteronism - K+ depletion - CHF
Acute gout.
Does not cross

8. Aztreonam ________ to penicillinase
- Oral Contraceptives
sedation - depression - nasal stuffiness - diarrhea
- Phenytoin
is resistant

9. ACE inhibitors - clinical use?
- N- acetylcystine
AV nodal cells
hypertension - CHF - diabetic renal disease
Inhibits reabsorption of uric acid.

10. What are three toxicities of Leuprolied?
-100% oxygen - hyperbaric
Digitoxin>95% Digoxin 75%
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
1. Antiandrogen 2. Nausea 3. Vomiting

11. Antiarrhythmic class IV- effects?
decrease conduction velocity - increase ERP - increase PR interval
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Quinidine - Amiodarone - Procainamide - Disopyramide
Prevents the release of Ca from SR of skeletal muscle

12. Decrease Digitoxin dose in renal failure?
- Tetracycline
NO
Erectile dysfunction.
Polymyxins

13. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
- Protamine
Tricyclic antidepressant.
Same as penicillin. Act as narrow spectrum antibiotics
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail

14. What are the four conditions in Which Omeprazole - Lansoprazole is used?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Non - Nucleosides
Carbachol - pilocarpine - physostigmine - echothiophate

15. What is the clinical use for Heparin?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
H2 antagonist

16. Toxicities associated with Acyclovir?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
sedation - depression - nasal stuffiness - diarrhea
- Formaldehyde & formic acid - severe acidosis & retinal damage
Delirium - Tremor - Nephrotoxicity

17. Which drug(s) cause this reaction: Adrenocortical Insufficiency
Albuterol - tertbutaline
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
- Glucocorticoid withdrawal
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

18. Mannitol - toxicity?
pulmonary edema - dehydration
Diuresis in pateints with sulfa allergy
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

19. What is the clinical use for Ampicillin and Amoxicillin?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Interstitial nephritis
Due to the presence of a bulkier R group

20. Which drug(s) cause this reaction: Gingival hyperplasia?
Slow - limited by half lives of clotting factors
- Cloazapine - carbamazapine - colchicine - PTU
It affects beta receptors equally and is used in AV heart block (rare).
- Phenytoin

21. What are two Alpha - glucosidase inhibitors?
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
- Tetracycline
1. Acarbose 2. Miglitol
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT

22. What effect would atropine have on a patient with peptic ulcer disease?
all of them
RESPIre
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.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

23. Digoxin v. Digitoxin: protein binding?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Digitoxin 70% Digoxin 20-40%
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
amphetamine and ephedrine

24. Dobutamine used for the tx of shock acts on Which receptors
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Beta1 more than B2
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
loop diuretics - thiazides

25. Adverse effects of Prazosin?
first dose orthostatic hypotension - dizziness - headache
Onchocerciasis ('river blindness'-- rIVER- mectin)
- Cloazapine - carbamazapine - colchicine - PTU
Lovastatin - Pravastatin - Simvastatin - Atorvastatin

26. Why would you give a drug like pancuronium or succinylcholine?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Useful in muscle paralysis during surgery or mechanical ventilation.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

27. Beta Blockers - CNS toxicity?
Norepinephrine
Penicillin.
- Lithium
sedation - sleep alterations

28. What drug is given for Pneumocystis carinii prophylaxis?
Pentamidine
Modification via Acetylation
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

29. What are the side effects of Rifampin?
Minor hepatotoxicity - Drug interactions (activates P450)
Ipratropium
Premature infants - because they lack UDP- glucuronyl transferase
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

30. What are common side effects of RT Inhibitors?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
aPTT (intrinsic pathway)
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Yes

31. How do you calculate maintenance dose?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Amphetamine and Ephedrine
cortical collecting tubule

32. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Delirium - Tremor - Nephrotoxicity
for RSV

33. What are the clinical uses for Aztreonam?
Increase target cell response to insulin.
Penicillin - V
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

34. Which drug(s) cause this reaction: P450 induction(6)?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
- aminoglycosides - loop diuretics - cisplatin
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.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

35. Resistance mechanisms for Vancomycin
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Ipratropium
- Ethosuxamide - sulfonamides - lamotrigine
Inhibits DNA dependent RNA polymerase

36. What is the MOA for the Aminoglycosides?
Topical and Oral - for Oral Candidiasis (Thrush)
- Penicillamine
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

37. What are five toxicities associated with Tacrolimus (FK506)?
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Small lipid - soluble molecule

38. What is the effect of TCA's on the adrenergic nerve?
Nephrotoxicity
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
No

39. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Large anionic polymer - acidic
Leukotrienes increasing bronchial tone.
Increases coumadin metabolism

40. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
Mg = Must go to the bathroom.
Premature infants - because they lack UDP- glucuronyl transferase
Beta antagonist.
- Bleomycin - amiodarone - busulfan

41. ADH antagonists - site of action?
collecting ducts
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Mg = Must go to the bathroom.
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

42. Name the common Azoles
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

43. What is the MOA for the Macrolides?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
effective in torsade de pointes and digoxin toxicity
Ipratropium

44. Resistance mechanisms for Chloramphenicol
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Useful in muscle paralysis during surgery or mechanical ventilation.
Modification via Acetylation
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.

45. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
- Tetracycline - amiodarone - sulfonamides
Hypersensitivity reactions
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

46. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Binds ergosterol - Disrupts fungal membranes
- Disulfram & also sulfonylureas - metronidazole
Stimulates beta adrenergic receptors

47. What are the major toxic side effects of Imipenem/cilastatin?
GI distress - Skin rash - and Seizures at high plasma levels
GI discomfort
Bleeding.
- Dimercaprol - succimer

48. Amiodarone - toxicity?
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Beta1 more than B2

49. Cocaine shares is mechanism of action with What antidepressant
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
TCA
Increases coumadin metabolism
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents

50. List five common glucocorticoids.
Pituitary hormone.
Hypersensitivity reactions
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Vd= (Amt. of drug in body/ Plasma drug conc.)