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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. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Beta -2 agonist.
Epinephirine(Alpha1 -2 and Beta 1 -2)
Protease Inhibitors and Reverse Transcriptase Inhibitors

2. For Warfarin What is the Onset of action
- polymyxins
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Slow - limited by half lives of clotting factors
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

3. Ethacrynic Acid - toxicity?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
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.
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise

4. How is Trimethoprim used clinically?
Used in combination therapy with SMZ to sequentially block folate synthesis
Hydralazine and Minoxidil
Binding to the presynaptic alpha 2 release modulating receptors
Cell membrane Ca2+ channels of cardiac sarcomere

5. Name the common Aminoglycosides (5)
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Yes - it does not cross the placenta.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Protease Inhibitors and Reverse Transcriptase Inhibitors

6. Describe the MOA of Interferons (INF)
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Liver
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

7. What type of gout is treated with Probenacid?
Chronic gout.
Binds to the Pyrophosphate Binding Site of the enzyme
- polymyxins
scopolamine

8. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Primaquine
Suramin
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

9. What is the clinical use of Tacrolimus (FK506)?
Acute gout.
Potent immunosuppressive used in organ transplant recipients.
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

10. What is the MOA of Ganciclovir?
Cyclooxygenases (COX I - COX II).
Inhibits CMV DNA polymerase
- Normalize K+ - Lidocaine - & Anti - dig Mab
-100% oxygen - hyperbaric

11. Which drug(s) cause this reaction: SLE- like syndrome?
- Hydralazine - Procainamide - INH - phenytoin
Binding to the presynaptic alpha 2 release modulating receptors
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
No - it inhibits the release of Nor Epi

12. What parasites are treated with Pyrantel Pamoate (more specific)?
GI disturbances.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

13. Antiarrhythmic class IB- effects?
Primaquine
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Beta1 more than B2
cardiac depression - peripheral edema - flushing - dizziness - constipation

14. Resistance mechanisms for Vancomycin
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
- Hydralazine - Procainamide - INH - phenytoin
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity

15. What is the category of drug names ending in - cycline (e.g. Tetracycline)
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
TCA
Antibiotic - protein synthesis inhibitor.
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

16. What are two types of drugs that interfere with the action of Sucralfate and why?
proarrhythmic
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.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
decrease

17. Which drug(s) cause this reaction: Anaphylaxis?
Methylxanthine.
- Penicillin
atropine - homatropine - tropicamide
Stimulates beta adrenergic receptors

18. Aztreonam is not usually...
Disulfiram - like reaction with EtOH - Headache
Large anionic polymer - acidic
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
toxic

19. What enzyme does Zileuton inhibit?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Methylation of rRNA near Erythromycin's ribosome binding site
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Lipoxygenase

20. What are three possible toxicities of NSAID usage?
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
pulmonary edema - dehydration
1. Renal damage 2. Aplastic anemia 3. GI distress

21. What are toxic side effects for Metronidazole?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
Disulfiram - like reaction with EtOH - Headache
Neutropenia

22. What type of patient should not take Misoprostol and why?
collecting ducts
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Ataxia - Dizziness - Slurred speech

23. What is the mechanism of action of Acetaminophen?
pulmonary edema - dehydration
Pseudomonas species and Gram - rods
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Interstitial nephritis

24. Antiarrhythmic class IV- toxicity?
These B-2 agonists cause respiratory smooth muscle to relax.
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

25. Acetazolamide - mechanism?
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Benzodiazepine.

26. Can Heparin be used during pregnancy?
Yes - it does not cross the placenta.
post MI and digitalis induced arrhythmias
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
AluMINIMUM amount of feces.

27. What are the side effects of Rifampin?
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
very short acting
Minor hepatotoxicity - Drug interactions (activates P450)
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

28. What are common side effects of Protease Inhibitors?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
proximal convoluted tubule - thin descending limb - and collecting duct
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Intrathecally

29. What is the category of drug names ending in - phylline (e.g. Theophylline)
Methylxanthine.
Cell membrane Ca2+ channels of cardiac sarcomere
IV vitamin K and fresh frozen plasma
Oral

30. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Early myocardial infarction.
Staphlococcus aureus
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Tricyclic antidepressant.

31. What are toxicities associated with Chloramphenicol?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
- Hydralazine - Procainamide - INH - phenytoin
Aplastic anemia (dose independent) - Gray Baby Syndrome

32. What are the side effects of Polymyxins?
Decreases synthesis of Mycolic Acid
Neurotoxicity - Acute renal tubular necrosis
- Physostigmine salicylate
Stimulates beta adrenergic receptors

33. List the specific antidote for this toxin: Methanol & Ethylene glycol
hypertension - CHF - diabetic renal disease
Decreases synthesis of Mycolic Acid
- Ethanol - dialysis - & fomepizole
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

34. What would be the effect on blood pressure with infusion of the alpha -2 agonist clonidine?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Beta - lactamase cleavage of Beta - lactam ring
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
fetal renal toxicity - hyperkalemia

35. Name the common Nucleoside Reverse Transcriptase Inhibitors
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Because they require some residual islet function.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

36. Which diuretics cause alkalosis?
proximal convoluted tubule - thin descending limb - and collecting duct
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
loop diuretics - thiazides
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

37. MOA: Disrupt bacterial/fungal cell membranes
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Pseudomonas species and Gram - rods
Polymyxins
Babiturate.

38. How can the t1/2 of INH be altered?
Chronic gout.
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Fast vs. Slow Acetylators
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

39. What are the Macrolides used for clinically?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH

40. What is the main clinical use for the thrombolytics?
YES
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Early myocardial infarction.
TMP- SMZ

41. What is the MOA of Amantadine?
Ca2+ (Loops Lose calcium)
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas

42. What cholinomimetics might your pt be taking for his glaucoma
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Carbachol - pilocarpine - physostigmine - echothiophate
Erectile dysfunction.
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

43. What are five possible toxic effects of Aspirin therapy?

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44. Steady state concentration is reached in __ number of half - lifes
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Chronic (weeks or months)
Megaloblastic anemia - Leukopenia - Granulocytopenia
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

45. What Sulfonamides are used for simple UTIs?
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
- ED 50 is less than the Km (less than 50% of receptors)
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Triple sulfas or SMZ

46. Which drug(s) cause this reaction: Photosensitivity(3)?
- Tetracycline - amiodarone - sulfonamides
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
competitive inhibirot of aldosterone in the cortical collecting tubule
proximal convoluted tubule - thin descending limb - and collecting duct

47. Name some common Sulfonamides (4)
bradycardia - AV block - CHF
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Disulfiram - like reaction with EtOH - Headache

48. Ca2+ channel blockers - clinical use?
hypertension - angina - arrhythmias
Topical and Oral - for Oral Candidiasis (Thrush)
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

49. For Heparin What is the Treatment for overdose
AZT
Cardiac glycoside (inotropic agent).
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Protamine sulfate

50. What are the major structural differences between Penicillin and Cephalosporin?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Rash - Pseudomembranous colitis
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).