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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. How does Ganciclovir's toxicity relate to that of Acyclovir?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Ganciclovir is more toxic to host enzymes
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
- Tetracycline - amiodarone - sulfonamides

2. What is Imipenem always administered with?
Cilastatin
Bleeding.
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
- Deferoxamine

3. What is a common drug interaction associated with Griseofulvin?
Increases coumadin metabolism
Give an antichloinesterase - neostigmine - edrophonium - etc
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.

4. How do spare receptors effect the Km?
Epinephirine(Alpha1 -2 and Beta 1 -2)
- ED 50 is less than the Km (less than 50% of receptors)
Botulinum
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

5. List the mechanism - clinical use - & toxicity of Tamoxifen.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Beta lactams - inhibit cell wall synthesis - Bactericidal
Activates antithrombin III

6. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Those patients who are taking nitrates.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
ACE inhibitor.
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

7. What is the mechanism of action of Misoprostol?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
- Vitamin K & fresh frozen plasma
- polymyxins

8. Hydralazine - clinical use?
severe hypertension - CHF
Penicillin - V
- Alkalinize urine & dialysis
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

9. Which drug(s) cause this reaction: Cardiac toxicity?
Praziquantel
With supplemental Folic Acid
- Daunorubicin & Doxorubicin
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

10. Which drug(s) cause this reaction: G6PD hemolysis(8)?
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Competitive inibitor of progestins at progesterone receptors.
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome

11. What is the mecanism of action of Sucralfate?
Epinephirine(Alpha1 -2 and Beta 1 -2)
Diarrhea
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
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.

12. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
all of them
Praziquantel
TMP- SMZ (DOC) - aerosolized pentamidine
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

13. What are two types of drugs that interfere with the action of Sucralfate and why?
- Bleomycin - amiodarone - busulfan
Interstitial nephritis
- Methylene blue
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

14. What is the mechanism of action of NSAIDs other than Aspirin?
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
RESPIre

15. Which drug(s) cause this reaction: Fanconi's syndrome?
- Tetracycline
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Modification via Acetylation - Adenylation - or Phosphorylation
Dermatophytes (tinea - ringworm)

16. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Epinephirine(Alpha1 -2 and Beta 1 -2)
- Lithium
Decreases synthesis of Mycolic Acid

17. How is Amphotericin B used clinically?
Tendonitis and Tendon rupture
Ca2+ (Loops Lose calcium)
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

18. What is the major side effect for Ampicillin and Amoxicillin?
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Hypersensitivity reactions
Used in combination therapy with SMZ to sequentially block folate synthesis
Rheumatoid and osteoarthritis.

19. MOA: Block protein synthesis at 50s subunit
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Hypersensitivity reactions
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

20. Name three calcium channel blockers?
- Steroids - Tamoxifen
Nifedipine - Verapamil - Diltiazem
Rash - Pseudomembranous colitis
- Nitrate - hydroxocobalamin thiosulfate

21. What is the memory key for the effect of aluminum hydroxide overuse?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
AluMINIMUM amount of feces.
Phosphorylation by a Viral Kinase
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

22. Which cancer drugs inhibit nucleotide synthesis(3)?
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Inhibition of 50S peptidyl transferase - Bacteriostatic
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
- Methotrexate - 5 FU - 6 mercaptopurine

23. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Inhalational general anesthetic.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Binding to the presynaptic alpha 2 release modulating receptors
Diarrhea

24. Name the common Nucleoside Reverse Transcriptase Inhibitors
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Inhibition of 50S peptidyl transferase - Bacteriostatic
Oxygen
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

25. What antimuscarinic agent is used in asthma and COPD?
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Ipratropium
Keratin containing tissues - e.g. - nails
Delirium - Tremor - Nephrotoxicity

26. Antiarrhythmic class IC- effects?
Rare.
The PT.
INH: Injures Neurons and Hepatocytes
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT

27. Resistance mechanisms for Aminoglycosides
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Rifampin (DOC) - minocycline
Aminoglycosides
Modification via Acetylation - Adenylation - or Phosphorylation

28. How is Ganciclovir used clinically?
Methicillin - Nafcillin - and Dicloxacillin
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Give an antichloinesterase - neostigmine - edrophonium - etc
CMV - esp in Immunocompromised patients

29. Which Aminoglycoside is used for Bowel Surgery ?
Neomycin
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Hemolytic anemia

30. How do Sulfonamides act on bacteria?
Foscarnet = pyroFosphate analog
- Glucagon
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Saquinavir - Ritonavir - Indinavir - Nelfinavir

31. How does angiotensin II affect NE release?
Pituitary hormone.
It acts presynaptically to increase NE release.
Digitoxin>95% Digoxin 75%
hypertension - angina - arrhythmias

32. A group of pts are rushed into the ER complaining of excessive sweating - tearing - salivation - HA - N and V - muscle twitching - difficulty breathing and diarrhea. What drug would be the most effective immediate tx
Inhibits CMV DNA polymerase
amphetamine and ephedrine
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

33. List the specific antidote for this toxin: Acetaminophen
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
collecting ducts
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- N- acetylcystine

34. What is the category of drug names ending in - ane (e.g. Halothane)
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Inhalational general anesthetic.
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Pituitary hormone.

35. What are three toxicities of Leuprolied?
Praziquantel
thick ascending limb
- Formaldehyde & formic acid - severe acidosis & retinal damage
1. Antiandrogen 2. Nausea 3. Vomiting

36. MOA: Block nucleotide synthesis
thiazides - amiloride
Sulfonamides - Trimethoprim
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased

37. How are the Latent Hypnozoite (Liver) forms of Malaria (P. vivax - P.ovale) treated?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Primaquine
Blocks Influenza A and RubellA; causes problems with the cerebellA
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

38. 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.
Cell membrane Ca2+ channels of cardiac sarcomere
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.

39. How is Griseofulvin used clinically?
- Steroids - Tamoxifen
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Oral treatment of superficial infections

40. Foscarnet does not require activation by a...
Sotalol - Ibutilide - Bretylium - Amiodarone
viral kinase
Teratogenic - Carcinogenic - Confusion - Headaches
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.

41. Resistance mechanisms for Vancomycin
Beta lactams - inhibit cell wall synthesis - Bactericidal
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
first dose orthostatic hypotension - dizziness - headache
Pseudomembranous colitis (C. difficile) - fever - diarrhea

42. What are the clinical indications for Azole therapy?
Ipratropium
- ACE inhibitors (Losartan>no cough)
Systemic mycoses
Pralidoxime regenerates active cholinesterase.

43. Which drug(s) cause this reaction: Aplastic anemia (5)?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Nitrates
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
It affects beta receptors equally and is used in AV heart block (rare).

44. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
Inhibt Assembly of new virus by Blocking Protease Enzyme
- Haloperidol - chlorpromazine - reserpine - MPTP
H2 antagonist
Neutropenia

45. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
hypertension - angina - arrhythmias
Aminoglycosides
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression

46. Are penicillinase resistant
Methicillin - Nafcillin - and Dicloxacillin
Cyclooxygenases (COX I - COX II).
thick ascending limb
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B

47. Antiarrhythmic class IC- toxicity?
penicillinase resistant
proarrhythmic
Quinolones
Carbenicillin - Piperacillin - and Ticarcillin

48. What effect would atropine have on the preganglionic sympathetic activation of sweat glands? Would this person sweat?
Acute (hours)
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Fast vs. Slow Acetylators
Interferes with microtubule function - disrupts mitosis - inhibits growth

49. Antiarrhythmic class IA effects?
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Does not cross
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

50. Name three ACE inhibitors?
Headache - flushing - dyspepsia - blue - green color vision.
Teratogenic - Carcinogenic - Confusion - Headaches
Captopril - Enalapril - Lisinopril
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.