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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 is the mecanism of action of Sucralfate?
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
- Nitrate - hydroxocobalamin thiosulfate
Pseudomembranous colitis (C. difficile) - fever - diarrhea
aPTT (intrinsic pathway)

2. What is combination TMP- SMZ used to treat?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Severe Gram - rod infections.
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

3. Which drug(s) cause this reaction: SLE- like syndrome?
- Hydralazine - Procainamide - INH - phenytoin
very short acting
The PT.
aPTT (intrinsic pathway)

4. Sotalol - toxicity?
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
torsade de pointes - excessive Beta block
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Ca2+ (Loops Lose calcium)

5. Acetazolamide - toxicity?
hyperaldosteronism - K+ depletion - CHF
Mebendazole/Thiabendazole - Pyrantel Pamoate
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

6. Name the common Azoles
- Ammonium Chloride
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Inhibits cell wall mucopeptide formation - Bactericidal
Protease inhibitor.

7. Mannitol - clinical use?
Same as penicillin. Extended spectrum antibiotics
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

8. Name four Antiarrhythmic drugs in class IA.
Quinidine - Amiodarone - Procainamide - Disopyramide
Digitoxin 168hrs Digoxin 40 hrs
Benzodiazepine.
Binds ergosterol - Disrupts fungal membranes

9. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Babiturate.
Chronic anticoagulation.

10. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
- polymyxins
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
Erectile dysfunction.
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

11. Which drug(s) cause this reaction: Cardiac toxicity?
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Rheumatoid and osteoarthritis.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
- Daunorubicin & Doxorubicin

12. ADH antagonists - site of action?
collecting ducts
Inhibits reabsorption of uric acid.
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

13. What are Aminoglycosides used for clinically?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
not a sulfonamide - but action is the same as furosemide
Severe Gram - rod infections.

14. Which drug(s) cause this reaction: Cough?
- ACE inhibitors (Losartan>no cough)
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
AZT - to reduce risk of Fetal Transmission

15. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
first dose orthostatic hypotension - dizziness - headache
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
- Haloperidol - chlorpromazine - reserpine - MPTP
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

16. List the specific antidote for this toxin: Lead
Rifampin
Oral treatment of superficial infections
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
- EDTA - dimercaprol - succimer - & penicillamine

17. What is Niclosamide used for?
Sotalol - Ibutilide - Bretylium - Amiodarone
1. Renal damage 2. Aplastic anemia 3. GI distress
thick ascending limb
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

18. Where does Griseofulvin deposit?
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Prevents the release of Ca from SR of skeletal muscle
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Keratin containing tissues - e.g. - nails

19. How is Foscarnet used clinically?
CMV Retinitis in IC pts When Ganciclovir fails
loop diuretics - thiazides
GI side effects. (Indomethacin is less toxic - more commonly used.)
Malaria (P. falciparum)

20. Mannitol - mechanism?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Spironolactone - Triamterene - Amiloride (the K+ STAys)
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

21. What is the category of drug names ending in - phylline (e.g. Theophylline)
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Sotalol - Ibutilide - Bretylium - Amiodarone
Short.
Methylxanthine.

22. What is a prerequisite for Acyclovir activation?
No - it inhibits the release of Nor Epi
GI upset
It must be Phosphorylated by Viral Thymidine Kinase
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)

23. Ca2+ channel blockers - mechanism?
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Heparin catalyzes the activation of antithrombin III.
Penicillin - G

24. What are four clinical activities of Aspirin?
- Tetracycline - amiodarone - sulfonamides
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)

25. MOA: Block protein synthesis at 30s subunit
Aminoglycosides - Tetracyclines
-100% oxygen - hyperbaric
- ED 50 is less than the Km (less than 50% of receptors)
Cell membrane Ca2+ channels of cardiac sarcomere

26. Which drug(s) cause this reaction: Aplastic anemia (5)?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
scopolamine
1. Acarbose 2. Miglitol
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

27. What enzyme does Zileuton inhibit?
Lipoxygenase
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Modification via Acetylation

28. What is the major side effect for Carbenicillin - Piperacillin - and Ticarcillin?
Systemic mycoses
Hypersensitivity reactions
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

29. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
Reversible block of histamine H2 receptors
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
very short acting
Acetylcholinesterase; ACh is broken down into choline and acetate.

30. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
Dopamine
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Polymyxins
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

31. What is the MOA for Nystatin?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Binds ergosterol - Disrupts fungal membranes
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
- Flumazenil

32. How would hemicholinium treatment affect cholinergic neurons?
- Oxalic acid - Acidosis & nephrotoxicity
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB

33. Explain pH dependent urinary drug elimination?
for RSV
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

34. What are three unwanted effects of Mifepristone?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
scopolamine
Malaria (P. falciparum)

35. List the specific antidote for this toxin: Tricyclic antidepressants
- NaHCO3
The PT.
Resistant Gram - infections
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

36. What is the category of drug names ending in - cillin (e.g. Methicillin)
sedation - positive Coombs' test
Penicillin.
Erectile dysfunction.
PT

37. What is the mechanism of action of the glucocorticoids?
Oral treatment of superficial infections
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
troponin - tropomyosin system
prevention of nodal arrhythmias (SVT)

38. What is Ketoconazole specifically used for?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
- Normalize K+ - Lidocaine - & Anti - dig Mab
- Aminocaproic acid

39. Guanethidine enhances the release of Norepi?
No - it inhibits the release of Nor Epi
Lipoxygenase
Useful in muscle paralysis during surgery or mechanical ventilation.
Succinylcholine

40. How is Ganciclovir activated?
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Leukotrienes increasing bronchial tone.
Phosphorylation by a Viral Kinase

41. Reserpine will block the syntheis of this drug and but not its precursor.
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Blocks Norepi - but not Dopamine
Lipoxygenase
Cardiac glycoside (inotropic agent).

42. Isopoterenol was given to a patient with a developing AV block - why?
Stimulates beta adrenergic receptors
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions

43. What do Aminoglycosides require for uptake?
Inhibits CMV DNA polymerase
Oxygen
Staphlococcus aureus
- Act on same receptor - Full has greater efficacy

44. Resistance mechanisms for Tetracycline
Short.
Decreased uptake or Increased transport out of cell
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Same as penicillin. Act as narrow spectrum antibiotics

45. Adverse effects of Loop Diuretics?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
- Phenytoin
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Premature infants - because they lack UDP- glucuronyl transferase

46. What organism is Imipenem/cilastatin the Drug of Choice for?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
- Disulfram & also sulfonylureas - metronidazole
Enterobacter
prevention of nodal arrhythmias (SVT)

47. Antimicrobial prophylaxis for PCP
Aminoglycosides - Tetracyclines
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
TMP- SMZ (DOC) - aerosolized pentamidine
Fast vs. Slow Acetylators

48. MOA: Bactericidal antibiotics
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
- Deferoxamine
Local anesthetic.
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

49. A common side effects of Interferon (INF) treatment is?
Pyridoxine (B6) administration
Neutropenia
H2 antagonist
Clavulanic acid

50. What is the MOA for Vancomycin?
- Haloperidol - chlorpromazine - reserpine - MPTP
Inhibits cell wall mucopeptide formation - Bactericidal
Sotalol - Ibutilide - Bretylium - Amiodarone
- Shifts the curve down - reduces Vmax