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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. What is a mnemonic to remember Amantadine's function?
AluMINIMUM amount of feces.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B

2. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Digitoxin 168hrs Digoxin 40 hrs
Cyclooxygenases (COX I - COX II).

3. Acetazolamide causes?

4. Name common Polymyxins
thiazides - amiloride
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Polymyxin B - Polymyxin E

5. What can result due to antacid overuse?
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
PT
Protamine sulfate
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

6. Quinidine - toxicity?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
GI distress - Skin rash - and Seizures at high plasma levels
- Disulfram & also sulfonylureas - metronidazole

7. Which RT inhibitors cause a Rash?
Non - Nucleosides
Aminoglycosides
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Ataxia - Dizziness - Slurred speech

8. What is the MOA for the Cephalosporins?
Polymyxin B - Polymyxin E
Beta lactams - inhibit cell wall synthesis - Bactericidal
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

9. Which cancer drugs inhibit nucleotide synthesis(3)?
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
- Physostigmine salicylate
- Methotrexate - 5 FU - 6 mercaptopurine
Competitive inibitor of progestins at progesterone receptors.

10. What are common side effects of Protease Inhibitors?
first dose orthostatic hypotension - dizziness - headache
Diuresis in pateints with sulfa allergy
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
BM suppression (neutropenia - anemia) - Peripheral neuropathy

11. How does a noncompetitive antagonist effect an agonist?
TMP- SMZ (DOC) - aerosolized pentamidine
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Buy AT 30 - CELL at 50'
- Shifts the curve down - reduces Vmax

12. What are three toxicities of Leuprolied?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
1. Antiandrogen 2. Nausea 3. Vomiting

13. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

14. Resistance mechanisms for Macrolides

15. Name four Antiarrhythmic drugs in class IA.
very short acting
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Stimulates beta adrenergic receptors
Quinidine - Amiodarone - Procainamide - Disopyramide

16. Antiarrhythmic class IV- toxicity?
Give an antichloinesterase - neostigmine - edrophonium - etc
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
- Vinca alkaloids(inhibit MT) - Paclitaxel
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

17. What is the difference in receptor affinity of epinephrine at low doses? High doses?

18. If a patient is given hexamethonium - What would happen to his/her heart rate?
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
GI upset - Superinfections - Skin rashes - Headache - Dizziness
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.
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

19. MOA: Block mRNA synthesis
aPTT (intrinsic pathway)
cyanide toxicity (releases CN)
Rifampin
Anaerobes

20. A common side effects of Interferon (INF) treatment is?
troponin - tropomyosin system
The only local anesthetic with vasoconstrictive properties.
Neutropenia
Beta1 more than B2

21. What is the category of drug names ending in - cillin (e.g. Methicillin)
Tricyclic antidepressant.
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Penicillin.
Interferes with microtubule function - disrupts mitosis - inhibits growth

22. K+ sparing diuretics - site of action?
cortical collecting tubule
RESPIre
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

23. List the specific antidote for this toxin: Methanol & Ethylene glycol
Na/K ATPase
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Acute gout.
- Ethanol - dialysis - & fomepizole

24. Adverse effects of Hydrochlorothiazide?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
- Lithium
depresses ectopic pacemakers - especially in digoxin toxicity

25. What is combination TMP- SMZ used to treat?
Pentavalent Antimony
- Flumazenil
Oxygen
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

26. What are three clinical uses of the Leuprolide?
Increase target cell response to insulin.
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Local anesthetic.

27. What is a prerequisite for Acyclovir activation?
- Physostigmine salicylate
- Tetracycline
IV vitamin K and fresh frozen plasma
It must be Phosphorylated by Viral Thymidine Kinase

28. What is the mechanism of action of NSAIDs other than Aspirin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Beta - lactamase cleavage of Beta - lactam ring
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

29. What is the mechanism of action of Clomiphene?
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
- N- acetylcystine
No - it inhibits the release of Nor Epi
very short acting

30. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
Inhibition of 50S peptidyl transferase - Bacteriostatic
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Doxycycline - because it is fecally eliminated
H2 antagonist

31. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
YES
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
- Quinidine - quinine

32. Name four Antiarrhythmic drugs in class III.
Large anionic polymer - acidic
Sotalol - Ibutilide - Bretylium - Amiodarone
Pretreat with antihistamines and a slow infusion rate
amphetamine and ephedrine

33. What is the mechanism of action of the glucocorticoids?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Antifungal.
RESPIre

34. Which RT inhibitors cause Lactic Acidosis?
Because they require some residual islet function.
toxic
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Nucleosides

35. Amiodarone - toxicity?
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Choline acetyltransferase
- Steroids - Tamoxifen
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

36. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Same as penicillin. Extended spectrum antibiotics
It must be Phosphorylated by Viral Thymidine Kinase

37. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Babiturate.
1. Weight gain 2. Hepatotoxicity (troglitazone)
Penicillin.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.

38. K+ sparing diuretics - toxicity?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
Megaloblastic anemia - Leukopenia - Granulocytopenia
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
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

39. Which drug(s) cause this reaction: Aplastic anemia (5)?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Flecainide - Encainide - Propafenone

40. As an Anes you want to use a depolarizing neuromuscular blocking drug on your pt - What do you use
Succinylcholine
Mg = Must go to the bathroom.
- Corticosteroids - heparin
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

41. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Hypersensitivity reactions
GET on the Metro

42. What is the MOA of Imipenem?
GI upset
Acts as a wide spectrum carbapenem
- Methotrexate - 5 FU - 6 mercaptopurine
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.

43. How does resistance to Vancomycin occur?
With an amino acid change of D- ala D- ala to D- ala D- lac
Beta lactams - inhibit cell wall synthesis - Bactericidal
- Alkalate DNA - Brain tumors - CNS toxicity
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B

44. ACE inhibitors - mechanism?
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Quinolones

45. Name three Antiarrhythmic drugs in class IB.
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Activates antithrombin III
Lidocaine - Mexiletine - Tocainide
Keratin containing tissues - e.g. - nails

46. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
Intrathecally
- Bleomycin - amiodarone - busulfan
Same as penicillin. Extended spectrum antibiotics
Chronic anticoagulation.

47. Isopoterenol was given to a patient with a developing AV block - why?
Foscarnet = pyroFosphate analog
fetal renal toxicity - hyperkalemia
Stimulates beta adrenergic 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.

48. ADH antagonists - site of action?
collecting ducts
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Topical and Oral - for Oral Candidiasis (Thrush)

49. What is the definition of zero - order kinetics? Example?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
- Ethosuxamide - sulfonamides - lamotrigine
for RSV
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

50. Which drug(s) cause this reaction: Gynecomastia (6)?
- Dimercaprol - succimer
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Hypersensitivity reactions
Neutropenia