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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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1. What is Ketoconazole specifically used for?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Sulfonamides - Trimethoprim
decrease
Inhibits DNA dependent RNA polymerase

2. Which drug(s) cause this reaction: Oto and Nephrotoxicity (3)?
proarrhythmic
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
- aminoglycosides - loop diuretics - cisplatin
H2 antagonist

3. What is the clincial use for Misoprostol?
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Blood
Pseudomonas species and Gram - rods
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.

4. Describe first - order kinetics?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Teratogenic - Carcinogenic - Confusion - Headaches
Constant FRACTION eliminated per unit time.(exponential)
Inhalational general anesthetic.

5. Antimicrobial prophylaxis for PCP
TMP- SMZ (DOC) - aerosolized pentamidine
Verapamil - Diltiazem - Bepridil
Babiturate.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction

6. K+- clinical use?
Rheumatoid and osteoarthritis.
Lipoxygenase
depresses ectopic pacemakers - especially in digoxin toxicity
Gemfibrozil - Clofibrate

7. What is the MOA of Ganciclovir?
Oral treatment of superficial infections
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Inhibits CMV DNA polymerase
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.

8. Quinidine - toxicity?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Norepinephrine (Alpha1 -2 and beta 1)
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Hypersensitivity reactions

9. What are common toxic side effects of Sulfonamides? (5)
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Minor hepatotoxicity - Drug interactions (activates P450)
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

10. How is Ribavirin used clinically?
Carbenicillin - Piperacillin - and Ticarcillin
Polymyxins
post MI and digitalis induced arrhythmias
for RSV

11. What is a Ribavirin toxicity?
Tricyclic antidepressant.
Hemolytic anemia
1. Pioglitazone 2. Rosiglitazone.
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

12. Ca2+ channel blockers - toxicity?
- Methylene blue
Succinylcholine
Sulfonamides - Trimethoprim
cardiac depression - peripheral edema - flushing - dizziness - constipation

13. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
Oral
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Decreases synthesis of Mycolic Acid

14. In What population does Gray Baby Syndrome occur? Why?
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Premature infants - because they lack UDP- glucuronyl transferase
Carbachol - pilocarpine - physostigmine - echothiophate

15. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Protamine sulfate
Competitive inibitor of progestins at progesterone receptors.
Binding to the presynaptic alpha 2 release modulating receptors

16. For Warfarin What is the Structure
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
ACE inhibitor.
Small lipid - soluble molecule
Tetracycline - Doxycycline - Demeclocycline - Minocycline

17. Why are the Sulfonylureas inactive in IDDM (type -1)?
Rare.
hypertension - angina - arrhythmias
Hypersensitivity reactions
Because they require some residual islet function.

18. For Heparin What is the Onset of action
Hypersensitivity reactions
Ca2+ (Loops Lose calcium)
Rapid (seconds)
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

19. MOA: Disrupt bacterial/fungal cell membranes
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
- Antipsychotics
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Polymyxins

20. What drug is used to diagnose myasthenia gravis?
CMV - esp in Immunocompromised patients
- polymyxins
edrophonium (extremely short acting anticholinesterase)
Hydralazine and Minoxidil

21. Is resistant to penicillinase?
Imipenem
- Dimercaprol - succimer
- Disulfram & also sulfonylureas - metronidazole
Teratogenic - Carcinogenic - Confusion - Headaches

22. What is the possible mechanism and effect of Metformin in treating diabetes?
Anaerobes
Cell membrane Ca2+ channels of cardiac sarcomere
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

23. What is the MOA for Clindamycin?
- Vitamin K & fresh frozen plasma
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Headache - flushing - dyspepsia - blue - green color vision.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

24. How would you treat African Trypanosomiasis (sleeping sickness)?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
These B-2 agonists cause respiratory smooth muscle to relax.
Suramin
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

25. What is the clinical use for Nystatin?
Topical and Oral - for Oral Candidiasis (Thrush)
- Chlorpromazine - thioridazine - haloperidol
Abortifacient.
Slow - limited by half lives of clotting factors

26. What is the effect of norepinephrine on bp and pulse pressure?
Sotalol - Ibutilide - Bretylium - Amiodarone
Beta antagonist.
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin

27. What is a common side effect of Misoprostol?
Diarrhea
Yes
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
No - hemicholinum block the uptake of Choline and thus Ach synthesis

28. What is Niclosamide used for?
Ipratropium
loop diuretics - thiazides
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

29. Does Warfarin have a long - medium - or short half life?
- Tetracycline - amiodarone - sulfonamides
Long.
AZT
Beta antagonist.

30. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Interferes with microtubule function - disrupts mitosis - inhibits growth
Heparin catalyzes the activation of antithrombin III.
- Bleomycin - amiodarone - busulfan

31. Which Tetracycline is used in patients with renal failure? / Why?
IV vitamin K and fresh frozen plasma
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Doxycycline - because it is fecally eliminated
cross - allergenic

32. Name two classes of drugs for HIV therapy
Protease Inhibitors and Reverse Transcriptase Inhibitors
Acetylcholine esterase
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
- N- acetylcystine

33. What are two toxicities associated with Cyclosporine?
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Headache - flushing - dyspepsia - blue - green color vision.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
propanolol - esmolol - metoprolol - atenolol - timolol

34. What is the memory key for the effect of magnesium hydroxide overuse?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Those patients who are taking nitrates.
Mg = Must go to the bathroom.
Inhibits reabsorption of uric acid.

35. What antimicrobial class is Aztreonam syngergestic with?
Aminoglycosides
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Mebendazole/Thiabendazole - Pyrantel Pamoate
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

36. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Diuresis in pateints with sulfa allergy
block Na+ channels in the cortical collecting tubule
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Nucleosides

37. What parasitic condition is treated with Ivermectin?

38. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
severe hypertension - CHF
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Amphetamine and Ephedrine
Methicillin - Nafcillin - and Dicloxacillin

39. If a patient is given hexamethonium - What would happen to his/her heart rate?
amphetamine and ephedrine
thiazides - amiloride
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.
Rash - Pseudomembranous colitis

40. What is the major side effect for Carbenicillin - Piperacillin - and Ticarcillin?
Hypersensitivity reactions
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Delirium - Tremor - Nephrotoxicity

41. What is Metronidazole combined with for 'triple therapy'? Against What organism?
- Tamoxifen
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

42. What can result due to antacid overuse?
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Give an antichloinesterase - neostigmine - edrophonium - etc
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.

43. What additional side effects exist for Ampicillin?
Rash - Pseudomembranous colitis
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

44. What type of gout is treated with Allopurinol?
1. Acarbose 2. Miglitol
Those patients who are taking nitrates.
Chronic gout.
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

45. What is the clinical use of Mifepristone (RU486)?
cholestyramine - colestipol
Rifampin (DOC) - minocycline
Abortifacient.
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

46. Furosemide - clinical use?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Slow - limited by half lives of clotting factors
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

47. What are the four conditions in Which Omeprazole - Lansoprazole is used?
- polymyxins
toxic
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

48. Foscarnet toxicity?
- Deferoxamine
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Nephrotoxicity
Sotalol - Ibutilide - Bretylium - Amiodarone

49. What is the mechanism of action of Misoprostol?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

50. What are the major toxic side effects of the Cephalosporins?
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Alpha -1 antagonist
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
- Glucocorticoid withdrawal