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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 is Leishmaniasis treated?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Liver
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Pentavalent Antimony

2. Decrease Digitoxin dose in renal failure?
DOC in diagnosing and abolishing AV nodal arrhythmias
NO
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
sedation - depression - nasal stuffiness - diarrhea

3. Quinidine - toxicity?
anuria - CHF
Bacitracin - Vancomycin
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Nevirapine - Delavirdine

4. Resistance mechanisms for Sulfonamides
No - hemicholinum block the uptake of Choline and thus Ach synthesis
- Quinidine - quinine
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

5. What cholinomimetics might your pt be taking for his glaucoma
Carbachol - pilocarpine - physostigmine - echothiophate
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Large anionic polymer - acidic
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

6. What is the possible mechanism and effect of Metformin in treating diabetes?
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

7. What musculo - skeletal side effects in Adults are associated with Floroquinolones?
Tendonitis and Tendon rupture
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
- Steroids - Tamoxifen
No - it inhibits the release of Nor Epi

8. Antiarrhythmic class IB- effects?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
It affects beta receptors equally and is used in AV heart block (rare).

9. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Same as penicillin. Extended spectrum antibiotics
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
- ACE inhibitors (Losartan>no cough)
Amphetamine and Ephedrine

10. What is the MOA for Trimethoprim (TMP)?
GI distress - Skin rash - and Seizures at high plasma levels
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Sotalol - Ibutilide - Bretylium - Amiodarone
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

11. Are Ampicillin and Amoxicillin are not...
penicillinase resistant
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Pralidoxime regenerates active cholinesterase.
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

12. Digoxin v. Digitoxin: half life?
Polymyxins
Digitoxin 168hrs Digoxin 40 hrs
- Normalize K+ - Lidocaine - & Anti - dig Mab
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid

13. What are common serious side effects of Aminoglycosides and What are these associated with?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
- Fluoroquinolones
Inhibition of 50S peptidyl transferase - Bacteriostatic
Spironolactone - Triamterene - Amiloride (the K+ STAys)

14. What are the clinical uses for 3rd Generation Cephalosporins?
Ataxia - Dizziness - Slurred speech
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
very short acting
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

15. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
cortical collecting tubule

16. Antimicrobial prophylaxis for a history of recurrent UTIs
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
TMP- SMZ
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
first dose orthostatic hypotension - dizziness - headache

17. What is a sign of toxicity with the use of thrombolytics?
Bleeding.
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Deferoxamine
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

18. What type of neurological blockade would hexamethonium create?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
- Steroids - Tamoxifen
Oxygen
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

19. What is Metronidazole combined with for 'triple therapy'? Against What organism?
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Botulinum
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

20. Digoxin v. Digitoxin: bioavailability?
Decreased uptake or Increased transport out of cell
local anesthetic. CNS stimulation or depression. CV depression.
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Digitoxin>95% Digoxin 75%

21. What is Nifurtimox administered for?

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22. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
Rapid (seconds)
proximal convoluted tubule
- Disulfram & also sulfonylureas - metronidazole
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

23. How do Sulfonamides act on bacteria?
- B51Naloxone / naltrexone (Narcan)
Oral
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia

24. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
- Haloperidol - chlorpromazine - reserpine - MPTP
Mebendazole/Thiabendazole - Pyrantel Pamoate
Yes - it does not cross the placenta.

25. List the mechanism - clinical use - & toxicity of Bleomycin.
sedation - depression - nasal stuffiness - diarrhea
edrophonium (extremely short acting anticholinesterase)
Butyrophenone (neuroleptic).
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

26. What are four H2 Blockers?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

27. Do Tetracyclines penetrate the CNS?
DOC in diagnosing and abolishing AV nodal arrhythmias
Pregnant women - Children; because animal studies show Damage to Cartilage
Minor hepatotoxicity - Drug interactions (activates P450)
Only in limited amounts

28. Toxic side effects of the Azoles?
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
- Nitrate - hydroxocobalamin thiosulfate
Rifampin
Oral treatment of superficial infections

29. Which individuals are predisposed to Sulfonamide - induced hemolysis?
Lidocaine - Mexiletine - Tocainide
sedation - sleep alterations
G6PD deficient individuals
block Na+ channels in the cortical collecting tubule

30. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
Mebendazole/Thiabendazole - Pyrantel Pamoate
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Tricyclic antidepressant.

31. How is Amphotericin B administered for fungal meningitis?
Chronic gout.
Intrathecally
- Hydralazine - Procainamide - INH - phenytoin
Early myocardial infarction.

32. What is the MOA for the Cephalosporins?
Doxycycline - because it is fecally eliminated
Protease Inhibitors and Reverse Transcriptase Inhibitors
Beta lactams - inhibit cell wall synthesis - Bactericidal
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

33. Which drug(s) cause this reaction: Gynecomastia (6)?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
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.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

34. What are two processes Corticosteroids inhibit leading to decreased inflammation?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Digoxin=urinary Digitoxin=biliary
dry mouth - sedation - severe rebound hypertension
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide

35. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Choline acetyltransferase
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Antifungal.
Succinylcholine

36. What is the most common cause of Pt noncompliance with Macrolides?
GI discomfort
Premature infants - because they lack UDP- glucuronyl transferase
Methylxanthine.
hypertension - CHF - diabetic renal disease

37. What conditions are treated with Metronidazole?
- Ammonium Chloride
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

38. How do you treat coma in the ER (4)?
Early myocardial infarction.
- Ammonium Chloride
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Prophylaxis for Influenza A - Rubella; Parkinson's disease

39. For Warfarin What is the Structure
AV nodal cells
Resistant Gram - infections
Small lipid - soluble molecule
Cell membrane Ca2+ channels of cardiac sarcomere

40. MOA: Bactericidal antibiotics
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

41. For Warfarin What is the Ability to inhibit coagulation in vitro
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
No
Cardiac glycoside (inotropic agent).

42. How are the Latent Hypnozoite (Liver) forms of Malaria (P. vivax - P.ovale) treated?
Inhibits CMV DNA polymerase
Acetylcholine esterase
Primaquine
- Nitrate - hydroxocobalamin thiosulfate

43. Which drug(s) cause this reaction: Photosensitivity(3)?
thick ascending limb
Early myocardial infarction.
Choline acetyltransferase
- Tetracycline - amiodarone - sulfonamides

44. What is the MOA for Clindamycin?
GI upset
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.
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux

45. Which diuretics cause acidosis?
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
carbonic anhydrase inhibitors - K+ sparing diuretics
Severe Gram - rod infections.
AZT

46. What is action of insulin in the liver - in muscle - and in adipose tissue?
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Methicillin - Nafcillin - and Dicloxacillin
Phosphorylation by a Viral Kinase

47. Why is there a drop in systolic - mean - and diastolic bp with infusion of isoproterenol?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Premature infants - because they lack UDP- glucuronyl transferase
- Glucagon
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time

48. What is the category of drug names ending in - cycline (e.g. Tetracycline)
- Glucagon
effective in torsade de pointes and digoxin toxicity
Antibiotic - protein synthesis inhibitor.
Those patients who are taking nitrates.

49. What is the mechanism of action of Ticlopidine - Clopidogrel
- Physostigmine salicylate
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
YES

50. What is the category of drug names ending in - tropin (e.g. Somatotropin)
edrophonium (extremely short acting anticholinesterase)
Pituitary hormone.
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Inhibits cell wall mucopeptide formation - Bactericidal