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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 two organisms Vancomycin is commonly used for?
troponin - tropomyosin system
- Tetracycline
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

2. Why would you use pralidoxime after exposure to an organophosphate?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
dry mouth - sedation - severe rebound hypertension
Pralidoxime regenerates active cholinesterase.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

3. What is the MOA for Nystatin?
Binds ergosterol - Disrupts fungal membranes
Hypersensitivity reactions
Antibiotic - protein synthesis inhibitor.
Used in combination therapy with SMZ to sequentially block folate synthesis

4. What is treated with Chloroquine - Quinine - Mefloquine?
cholestyramine - colestipol
Malaria (P. falciparum)
Foscarnet = pyroFosphate analog
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

5. Hydralazine - clinical use?
severe hypertension - CHF
VACUUM your Bed Room'
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

6. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Prevents the release of ACh - Which results in muscle paralysis.
No - warfarin - unlike heparin - can cross the placenta.

7. Which drug(s) cause this reaction: Tendonitis and rupture?
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Pralidoxime regenerates active cholinesterase.
dry mouth - sedation - severe rebound hypertension
- Fluoroquinolones

8. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
- Ethanol - dialysis - & fomepizole
is resistant
Epinephirine(Alpha1 -2 and Beta 1 -2)
Yes - it does not cross the placenta.

9. What Sulfonamides are used for simple UTIs?
VACUUM your Bed Room'
Triple sulfas or SMZ
Diuresis in pateints with sulfa allergy
sedation - depression - nasal stuffiness - diarrhea

10. Acetazolamide - toxicity?
amphetamine and ephedrine
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)

11. How is Ribavirin used clinically?
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
for RSV
NO

12. Nifedipine has similar action to?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
- Penicillamine
Nitrates
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

13. What are the major toxic side effects of the Cephalosporins?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Rash - Pseudomembranous colitis

14. Which drug(s) cause this reaction: P450 inhibition(6)?
NO
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

15. Name two classes of drugs for HIV therapy
Fast vs. Slow Acetylators
Inhibits DNA dependent RNA polymerase
Protease Inhibitors and Reverse Transcriptase Inhibitors
Same as penicillin. Extended spectrum antibiotics

16. What are four Sulfonylureas?
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Nephrotoxicity
Imipenem
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

17. How can Isoniazid (INH)- induced neurotoxicity be prevented?
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Foscarnet = pyroFosphate analog
Pyridoxine (B6) administration
Minor hepatotoxicity - Drug interactions (activates P450)

18. The COX-2 inhibitors (celecoxib - rofecoxib) have similar side effects to the NSAIDs with What one exception?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
effective in torsade de pointes and digoxin toxicity
edrophonium (extremely short acting anticholinesterase)

19. List the mechanism - clinical use - & toxicity of Tamoxifen.
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

20. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Hypersensitivity reactions
It affects beta receptors equally and is used in AV heart block (rare).
Indomethacin is used to close a patent ductus arteriosus.

21. Antimicrobial prophylaxis for a history of recurrent UTIs
TMP- SMZ
Norepinephrine
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
GI disturbances.

22. What enzyme does Zileuton inhibit?
Sotalol - Ibutilide - Bretylium - Amiodarone
Lipoxygenase
Buy AT 30 - CELL at 50'
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

23. Decrease Digitoxin dose in renal failure?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
carbonic anhydrase inhibitors - K+ sparing diuretics
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
NO

24. List the specific antidote for this toxin: Tricyclic antidepressants
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
- NaHCO3
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

25. Which drug(s) cause this reaction: Osteoporosis (2)?
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
- Corticosteroids - heparin
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Cephalosporins

26. List the specific antidote for this toxin: Beta Blockers
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
for RSV
- Glucagon
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

27. What is a common drug interaction associated with Griseofulvin?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Increases coumadin metabolism
AZT - to reduce risk of Fetal Transmission
No - warfarin - unlike heparin - can cross the placenta.

28. What is an additional side effect of Methicillin?
Binding to the presynaptic alpha 2 release modulating receptors
Interstitial nephritis
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

29. What are the phases of succinylcholine neuromuscular blockade?
Bleeding.
DOC in diagnosing and abolishing AV nodal arrhythmias
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Delirium - Tremor - Nephrotoxicity

30. Name three Antiarrhythmic drugs in class IB.
TCA
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Doxycycline - because it is fecally eliminated
Lidocaine - Mexiletine - Tocainide

31. What are Amantadine - associated side effects?
Cephalosporins
Clavulanic acid
Ataxia - Dizziness - Slurred speech
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome

32. What is the mechanism of Azathioprine?
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

33. In coma situations you rule out What (7)?

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34. What is Ketoconazole specifically used for?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Edrophonium
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

35. What do Aminoglycosides require for uptake?
Does not cross
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Oxygen

36. Hydrochlorothiazide - clinical use?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Penicillin - V
Chronic gout.
HTN - CHF - calcium stone formation - nephrogenic DI.

37. What neurotransmitter does Amantadine affect? How does it influence this NT?
Oxygen
- EDTA - dimercaprol - succimer - & penicillamine
physostigmine
Dopamine; causes its release from intact nerve terminals

38. List the specific antidote for this toxin: Carbon monoxide
-100% oxygen - hyperbaric
Diuresis in pateints with sulfa allergy
Quinidine - Amiodarone - Procainamide - Disopyramide
HTN - CHF - calcium stone formation - nephrogenic DI.

39. What are three complications of Warfarin usage?
It affects beta receptors equally and is used in AV heart block (rare).
Nucleosides
troponin - tropomyosin system
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions

40. MOA: Disrupt fungal cell membranes
Amphotericin B - Nystatin - Fluconazole/azoles
- Aminocaproic acid
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

41. What are four clinical uses of glucocorticoids?

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42. What are four thrombolytics?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
H2 antagonist
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

43. Beta Blockers - site of action?
Acetylcholinesterase; ACh is broken down into choline and acetate.
Ipratropium
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Cyclooxygenases (COX I - COX II).

44. Explain potency in relation to full and partial agonists(2).
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
ACE inhibitor.

45. What are Polymyxins used for?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Resistant Gram - infections
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
proximal convoluted tubule

46. What is the mechanism of action of the H2 Blockers?
Reversible block of histamine H2 receptors
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Liver
PT

47. Antiarrhythmic class IC- toxicity?
proarrhythmic
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

48. What is the MOA of Aztreonam?
Only in limited amounts
Amphotericin B - Nystatin - Fluconazole/azoles
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

49. Which drug(s) cause this reaction: Hot flashes?
Quinidine - Amiodarone - Procainamide - Disopyramide
Chronic gout.
- Tamoxifen
Methylxanthine.

50. Why is Cilastatin administered with Imipenem?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Slow - limited by half lives of clotting factors
Same as penicillin. Act as narrow spectrum antibiotics
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.