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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. K+ sparing diuretics - clinical use?
Aminoglycosides
hyperaldosteronism - K+ depletion - CHF
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

2. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
IV vitamin K and fresh frozen plasma
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Hypersensitivity reactions

3. What is the loading dose formula?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Cilastatin

4. Describe Phase II metabolism in liver(3)?
hyperaldosteronism - K+ depletion - CHF
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Long.
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

5. Antiarrhythmic class IV- toxicity?
Antibiotic - protein synthesis inhibitor.
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
PT

6. What enzyme is responsible for the degredation of Ach
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Acetylcholine esterase
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

7. Beta Blockers - BP?
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Acetylcholinesterase; ACh is broken down into choline and acetate.
decrease

8. MOA of Succinylcholine
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Prevents the release of Ca from SR of skeletal muscle
- B51Naloxone / naltrexone (Narcan)

9. What is Niclosamide used for?
pulmonary edema - dehydration
Edrophonium
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

10. Which diuretics increase urine K+?
Primaquine
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

11. What is the mechanism of action of Acetaminophen?
Oxygen
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Intrathecally
Beta1 more than B2

12. Name the common Nucleoside Reverse Transcriptase Inhibitors
aPTT (intrinsic pathway)
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
CMV - esp in Immunocompromised patients

13. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Digitoxin 70% Digoxin 20-40%
Pseudomonas species and Gram - rods
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Enterobacter

14. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
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
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Fast vs. Slow Acetylators

15. Which RT inhibitors cause Lactic Acidosis?
Interferes with microtubule function - disrupts mitosis - inhibits growth
Nucleosides
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.
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

16. What is the MOA for Nystatin?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Gemfibrozil - Clofibrate
Binds ergosterol - Disrupts fungal membranes
dizziness - flushing - constipation (verapamil) - nausea

17. While at a tail gait party - you bite into a sandwich that a yellow jacket is also enjoying. Knowing your allergy to this creature - What should you do?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Cell membrane Ca2+ channels of cardiac sarcomere
NO

18. Name four HMG- CoA reductase inhibitors.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
hypertension - angina - arrhythmias
Digitoxin>95% Digoxin 75%
Chronic gout.

19. Which drug(s) cause this reaction: P450 inhibition(6)?
1. Acarbose 2. Miglitol
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
It affects beta receptors equally and is used in AV heart block (rare).
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.

20. What conditions are treated with Metronidazole?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
1. Acarbose 2. Miglitol
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Chronic gout.

21. What are the clinical indications for bethanechol?
DOC in diagnosing and abolishing AV nodal arrhythmias
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Amphotericin B - Nystatin - Fluconazole/azoles
No - hemicholinum block the uptake of Choline and thus Ach synthesis

22. List the specific antidote for this toxin: Tricyclic antidepressants
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Pregnant women - Children; because animal studies show Damage to Cartilage
Norepinephrine
- NaHCO3

23. Cautions When using Amiodarone?
Nifedipine - Verapamil - Diltiazem
check PFTs - LFTs - and TFTs
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

24. What is the mechanism of action of NSAIDs other than Aspirin?
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.
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Praziquantel
It acts presynaptically to increase NE release.

25. Ganciclovir associated toxicities?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

26. Furosemide increases the excretion of What ion?
Ca2+ (Loops Lose calcium)
Rare.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
- Tamoxifen

27. What is the MOA of Ganciclovir?
Inhibits CMV DNA polymerase
Headache - flushing - dyspepsia - blue - green color vision.
AZT
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

28. How is Rifampin used clinically?
thiazides - amiloride
- NaHCO3
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

29. How do Sulfonamides act on bacteria?
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Non - Nucleosides
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
- Glucocorticoid withdrawal

30. What are the clinical indications for Azole therapy?
proximal convoluted tubule - thin descending limb - and collecting duct
The PTT.
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Systemic mycoses

31. Which diuretics increase urine Ca2+?
Epinephrine
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
loop diuretics - spironolactone
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)

32. Your patient wants an effective drug to treat his motion sickness - What would you prescribe
Sildenafil fills the penis
Lipoxygenase
- Shifts the curve down - reduces Vmax
Scopolamine

33. What is the mechanism of action of Aspirin?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
The only local anesthetic with vasoconstrictive properties.

34. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Hypersensitivity reactions
Pregnant women - Children; because animal studies show Damage to Cartilage
Due to the presence of a bulkier R group

35. List the specific antidote for this toxin: Antimuscarinic (anticholinergic)
- Disulfram & also sulfonylureas - metronidazole
- Physostigmine salicylate
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

36. What microorganisms is Aztreonam not effective against?
Mebendazole/Thiabendazole - Pyrantel Pamoate
1. Renal damage 2. Aplastic anemia 3. GI distress
Gram + and Anerobes
Constant FRACTION eliminated per unit time.(exponential)

37. K+ sparing diuretics - site of action?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Blood
Gram + and Anerobes
cortical collecting tubule

38. Why is carbachol and pilocarpine useful in treatment of glaucoma?
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
physostigmine
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Cilastatin

39. What is Imipenem always administered with?
Cilastatin
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Quinidine - Amiodarone - Procainamide - Disopyramide

40. What are Amantadine - associated side effects?
Ataxia - Dizziness - Slurred speech
anuria - CHF
Nevirapine - Delavirdine
Protamine sulfate

41. List the mechanism - clinical use - & toxicity of Cyclophosphamide.
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Ganciclovir is more toxic to host enzymes

42. Common side effects associated with Clindamycin include?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Alpha -1 antagonist
Peptic ulcer disease.
1. Pioglitazone 2. Rosiglitazone.

43. Aztreonam ________ to penicillinase
DOC in diagnosing and abolishing AV nodal arrhythmias
is resistant
TMP- SMZ
Hydralazine and Minoxidil

44. What are the nondepolarizing neuromuscular blocking drugs?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism

45. How is Amphotericin B used clinically?
Nifedipine - Verapamil - Diltiazem
ACIDazolamide' causes acidosis
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Blood

46. Resistance mechanisms for Aminoglycosides
Non - Nucleosides
- Bleomycin - amiodarone - busulfan
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Modification via Acetylation - Adenylation - or Phosphorylation

47. What is the formula for Clearance (CL)
CL= (rate of elimination of drug/ Plasma drug conc.)
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
- N- acetylcystine
Polymyxins

48. What are Aminoglycosides used for clinically?
Rifampin
Severe Gram - rod infections.
Erythromycin - Azithromycin - Clarithromycin
Decreases synthesis of Mycolic Acid

49. What is the category of drug names ending in - tropin (e.g. Somatotropin)
Pituitary hormone.
Sulfonamides - Trimethoprim
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

50. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
The only local anesthetic with vasoconstrictive properties.
Hydralazine and Minoxidil
Beta Blockers
Quinidine - Amiodarone - Procainamide - Disopyramide