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USMLE Step 1 Pharmacology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Yes - it does not cross the placenta.
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
INH: Injures Neurons and Hepatocytes

2. Isopoterenol was given to a patient with a developing AV block - why?
Pseudomonas species and Gram - rods
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Stimulates beta adrenergic receptors
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.

3. MOA: Block protein synthesis at 50s subunit
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
- Fluoroquinolones
- Methotrexate - 5 FU - 6 mercaptopurine
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

4. What is the possible mechanism and effect of Metformin in treating diabetes?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
- Penicillamine
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic

5. Antiarrhythmic class IV- clinical use?
for RSV
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Captopril - Enalapril - Lisinopril
prevention of nodal arrhythmias (SVT)

6. What are are the Sulfonylureas (general description) and What is their use?
Inhibt Assembly of new virus by Blocking Protease Enzyme
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
- Tricyclic antidepressants
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

7. For Warfarin What is the Lab value to monitor
PT
Gemfibrozil - Clofibrate
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

8. What are the products and their toxicities of the metabolism of Methanol by / alcohol dehydrogenase?
GI distress - Skin rash - and Seizures at high plasma levels
YES
Alpha -1 antagonist
- Formaldehyde & formic acid - severe acidosis & retinal damage

9. Name five Antiarrhythmic drugs in class II?
AZT
dizziness - flushing - constipation (verapamil) - nausea
propanolol - esmolol - metoprolol - atenolol - timolol
Same as penicillin. Extended spectrum antibiotics

10. What musculo - skeletal side effects in Adults are associated with Floroquinolones?
loop diuretics - spironolactone
Tendonitis and Tendon rupture
Benzathine penicillin G
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

11. Why is reserpine effective in treating HTN?
Clavulanic acid
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Suramin
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

12. What is the clinical use for Clomiphene?
- Atropine & pralidoxime
Binds ergosterol - Disrupts fungal membranes
Digoxin=urinary Digitoxin=biliary
Treatment of infertility.

13. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Choline acetyltransferase
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

14. What is the MOA of Imipenem?
Binding to the presynaptic alpha 2 release modulating receptors
dry mouth - sedation - severe rebound hypertension
Gemfibrozil - Clofibrate
Acts as a wide spectrum carbapenem

15. How do you calculate maintenance dose?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Pentamidine
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Beta antagonist.

16. Name the common Nucleoside Reverse Transcriptase Inhibitors
- Flumazenil
Pretreat with antihistamines and a slow infusion rate
reversible SLE- like syndrome
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

17. Which drug(s) cause this reaction: Pseudomembranous colitis?
- Clindamycin
Acute gout.
For serious - Gram + multidrug - resistant organisms
edrophonium (extremely short acting anticholinesterase)

18. Name three Antiarrhythmic drugs in class IC.
Yes - it does not cross the placenta.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Flecainide - Encainide - Propafenone
- EDTA - dimercaprol - succimer - & penicillamine

19. Digoxin v. Digitoxin: half life?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Mebendazole/Thiabendazole - Pyrantel Pamoate
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Digitoxin 168hrs Digoxin 40 hrs

20. What are two toxicities associated with Cyclosporine?
Leukotrienes increasing bronchial tone.
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

21. What microorganisms are clinical indications for Tetracycline therapy?

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22. Which drug(s) cause this reaction: Cinchonism (2)?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Dopamine; causes its release from intact nerve terminals
- Quinidine - quinine
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

23. Which drug(s) cause this reaction: Tardive dyskinesia?
Lipoxygenase
Paranteral (IV - SC)
blocks SR Ca2+ channels
- Antipsychotics

24. What are Fluoroquinolones indicated for? (3)
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
physostigmine
- Shifts the curve to the right - increases Km
Chronic anticoagulation.

25. Esmolol - short or long acting?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Binds to the Pyrophosphate Binding Site of the enzyme
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
very short acting

26. Which diuretics increase urine K+?
- Deferoxamine
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Bleeding.
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

27. What is the MOA for Amphotericin B?
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Sulfonamides - Trimethoprim
local anesthetic. CNS stimulation or depression. CV depression.

28. What drug is used to diagnose myasthenia gravis?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
edrophonium (extremely short acting anticholinesterase)
Aplastic anemia (dose independent) - Gray Baby Syndrome
Imipenem

29. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Small lipid - soluble molecule
- Chloramphenicol
Hypersensitivity reactions

30. What are two processes Corticosteroids inhibit leading to decreased inflammation?
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Beta -2 agonist.
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)

31. What are common toxicities related to Vancomycin therapy?

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32. Which RT inhibitors cause a Rash?
Oral
Non - Nucleosides
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Imipenem

33. How would you reverse the effect of a neuromuscular blocking agent?
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Give an antichloinesterase - neostigmine - edrophonium - etc
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

34. A common side effects of Interferon (INF) treatment is?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
- Tricyclic antidepressants
Neutropenia
No - warfarin - unlike heparin - can cross the placenta.

35. What is Imipenem always administered with?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Cilastatin
Due to the presence of a bulkier R group
HTN - CHF - calcium stone formation - nephrogenic DI.

36. Beta Blockers - BP?
Staphlococcus aureus
Diarrhea
decrease
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.

37. What anticholinesterase crosses the blood - brain - barrier?
distal convoluted tubule (early)
Oral treatment of superficial infections
physostigmine
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

38. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Captopril - Enalapril - Lisinopril
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Those patients who are taking nitrates.

39. What is the only depolarizing neuromuscular blocking agent?
Succinylcholine
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Long.
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

40. How does dantrolene work?
is resistant
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
hypertension - CHF - diabetic renal disease
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.

41. What are common toxicities associated with Tetracyclines?

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42. Which Aminoglycoside is used for Bowel Surgery ?
Butyrophenone (neuroleptic).
Inhibits CMV DNA polymerase
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Neomycin

43. What is the formula for Volume of distribution (Vd)
Give an antichloinesterase - neostigmine - edrophonium - etc
Vd= (Amt. of drug in body/ Plasma drug conc.)
TCA
Suramin

44. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
CL= (rate of elimination of drug/ Plasma drug conc.)
Treatment of infertility.
- Chlorpromazine - thioridazine - haloperidol
- Penicillamine

45. Which Tetracycline is used in patients with renal failure? / Why?
Dopamine; causes its release from intact nerve terminals
is resistant
Doxycycline - because it is fecally eliminated
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

46. Name two organisms Vancomycin is commonly used for?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Ataxia - Dizziness - Slurred speech
Rash - Pseudomembranous colitis
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

47. Decrease Digitoxin dose in renal failure?
H2 antagonist
Tetracycline - Doxycycline - Demeclocycline - Minocycline
NO
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

48. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
distal convoluted tubule (early)
H2 antagonist
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

49. How is Foscarnet used clinically?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
CMV Retinitis in IC pts When Ganciclovir fails
- Bleomycin - amiodarone - busulfan
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole

50. Which receptors does phenylephrine act upon?
Because they require some residual islet function.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Inhibit Ergosterol synthesis