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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. Which drug(s) cause this reaction: Torsade de pointes (2)?
Sulfonamides - Trimethoprim
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Megaloblastic anemia - Leukopenia - Granulocytopenia
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

2. What are the clinical uses for 2nd Generation Cephalosporins?
- Shifts the curve to the right - increases Km
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Sotalol - Ibutilide - Bretylium - Amiodarone
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

3. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
Protamine sulfate
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Intrathecally
- Chlorpromazine - thioridazine - haloperidol

4. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
AmOxicillin has greater Oral bioavailability
Give an antichloinesterase - neostigmine - edrophonium - etc

5. What are the clinical uses for Ticlopidine - Clopidogrel?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Nifedipine - Verapamil - Diltiazem
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

6. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

7. Mnemonic for Foscarnet?
Foscarnet = pyroFosphate analog
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Prevents the release of ACh - Which results in muscle paralysis.
Hypersensitivity reactions

8. List the specific antidote for this toxin: Benzodiazepines
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
- Flumazenil
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

9. What is a Ribavirin toxicity?
AZT
These B-2 agonists cause respiratory smooth muscle to relax.
Hemolytic anemia
Fast vs. Slow Acetylators

10. Beta Blockers - site of action?
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
AZT - to reduce risk of Fetal Transmission
1. Acarbose 2. Miglitol
Beta adrenergic receptors and Ca2+ channels (stimulatory)

11. What is the clinical use for Ampicillin and Amoxicillin?
Gram + and Anerobes
Rifampin (DOC) - minocycline
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods

12. List the mechanism - clinical use - & toxicity of Cisplatin.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Diarrhea
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

13. Which drug(s) cause this reaction: Cardiac toxicity?
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- Daunorubicin & Doxorubicin
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
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

14. What are three types of antacids and the problems that can result from their overuse?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

15. Name four HMG- CoA reductase inhibitors.
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
DHPG (dihydroxy-2- propoxymethyl guanine)
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

16. What is the memory key for Metronidazole's clinical uses?
- Clindamycin
GET on the Metro
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide

17. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
Babiturate.
Beta - lactam antibiotics
penicillinase resistant
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

18. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Succinylcholine
Due to the presence of a bulkier R group
Neurotoxicity - Acute renal tubular necrosis

19. Name three Antiarrhythmic drugs in class IC.
dizziness - flushing - constipation (verapamil) - nausea
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Flecainide - Encainide - Propafenone
Used in combination therapy with SMZ to sequentially block folate synthesis

20. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Keratin containing tissues - e.g. - nails
Clavulanic acid
ACIDazolamide' causes acidosis

21. What is the clinical use for Heparin?
Intrathecally
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
competitive inhibirot of aldosterone in the cortical collecting tubule

22. What are four clinical uses of glucocorticoids?

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23. Hydrochlorothiazide - clinical use?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
HTN - CHF - calcium stone formation - nephrogenic DI.
penicillinase resistant
cholestyramine - colestipol

24. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
Mebendazole/Thiabendazole - Pyrantel Pamoate
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Yes
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)

25. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Nifedipine - Verapamil - Diltiazem
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Choline acetyltransferase
Hypersensitivity reactions

26. Do Tetracyclines penetrate the CNS?
Only in limited amounts
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome

27. Bretyllium - toxicity?
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
new arrhythmias - hypotension
Cephalosporins

28. What enzyme is responsible for the degredation of Ach
Indirect agonist - uptake inhibitor
- Daunorubicin & Doxorubicin
Acetylcholine esterase
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

29. What is the clinical use for Nystatin?
Topical and Oral - for Oral Candidiasis (Thrush)
CMV Retinitis in IC pts When Ganciclovir fails
Same as penicillin. Act as narrow spectrum antibiotics
Early myocardial infarction.

30. K+- clinical use?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
not a sulfonamide - but action is the same as furosemide
depresses ectopic pacemakers - especially in digoxin toxicity
GI distress - Skin rash - and Seizures at high plasma levels

31. What is the memory aid for subunit distribution of ribosomal inhibitors?

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32. Ethacrynic Acid - mechanism?
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
TCA
- Aminocaproic acid
not a sulfonamide - but action is the same as furosemide

33. What is the memory key for the action of Sildenafil (Viagra)?
Hydralazine and Minoxidil
Digitoxin 168hrs Digoxin 40 hrs
- Ammonium Chloride
Sildenafil fills the penis

34. Acetazolamide - clinical uses?
Anaerobes
Cyclooxygenases (COX I - COX II).
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

35. What is the MOA of Aztreonam?
hyperaldosteronism - K+ depletion - CHF
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Carbenicillin - Piperacillin - and Ticarcillin

36. What is the mechanism of action of Acetaminophen?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Severe Gram - rod infections.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Sotalol - Ibutilide - Bretylium - Amiodarone

37. ACE inhibitors - mechanism?
Benzodiazepine.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

38. MOA: Block protein synthesis at 50s subunit
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

39. What is the clinical utility of clonidine?
INH: Injures Neurons and Hepatocytes
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Small lipid - soluble molecule
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.

40. What are two clinical uses of Azathioprine?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Oral treatment of superficial infections
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

41. Antimicrobial prophylaxis for Meningococcal infection
Rifampin (DOC) - minocycline
- Lithium
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
- Glucagon

42. Acetazolamide causes?

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43. Adverse effects of beta - blockers?
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Pretreat with antihistamines and a slow infusion rate

44. What reversal agent could a Anes give to reverse the effects of Atropine
With supplemental Folic Acid
Bethanechol - Neostigmine - physostigmine
Inhibits DNA dependent RNA polymerase
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

45. What is the MOA of Imipenem?
Malaria (P. falciparum)
Acts as a wide spectrum carbapenem
new arrhythmias - hypotension
reversible SLE- like syndrome

46. 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.
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
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.
- Lithium

47. Decrease Digitoxin dose in renal failure?
NO
Epinephrine
Severe Gram - rod infections.
It affects beta receptors equally and is used in AV heart block (rare).

48. Thiazides - site of action?
distal convoluted tubule (early)
1. Weight gain 2. Hepatotoxicity (troglitazone)
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

49. What are two indirect acting adrenergic agonists?
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
amphetamine and ephedrine
Rifampin
Binds to the Pyrophosphate Binding Site of the enzyme

50. What is the memory key involving the '4 R's of Rifampin?'
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Aplastic anemia (dose independent) - Gray Baby Syndrome