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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. What is the category and mechanism of action of Zileuton in Asthma treatment?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Antileukotriene; blocks synthesis by lipoxygenase.
Interferes with microtubule function - disrupts mitosis - inhibits growth
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

2. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
Same as penicillin. Act as narrow spectrum antibiotics
Verapamil - Diltiazem - Bepridil
Beta antagonist.
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

3. What is an occasional side effect of Aztreonam?
Neurotoxicity - Acute renal tubular necrosis
pulmonary edema - dehydration
TMP- SMZ
GI upset

4. What class of drug is echothiophate? What is its indication?
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
anticholinesterase glaucoma
Methicillin - Nafcillin - and Dicloxacillin
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.

5. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Antifungal.
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
Acute (hours)
torsade de pointes - excessive Beta block

6. Name some common Tetracyclines (4)
Edrophonium
Tetracycline - Doxycycline - Demeclocycline - Minocycline
proarrhythmic
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

7. Name the Protease Inhibitors (4)
Because they require some residual islet function.
Pentamidine
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Saquinavir - Ritonavir - Indinavir - Nelfinavir

8. For Heparin What is the Structure
- Chlorpromazine - thioridazine - haloperidol
- Lithium
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Large anionic polymer - acidic

9. Why would you use pralidoxime after exposure to an organophosphate?
Pralidoxime regenerates active cholinesterase.
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Beta - lactam antibiotics

10. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Slow - limited by half lives of clotting factors
Keratin containing tissues - e.g. - nails
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Short.

11. What are Fluoroquinolones indicated for? (3)
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

12. ACE inhibitors - toxicity?
Digitoxin 168hrs Digoxin 40 hrs
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Because they require some residual islet function.
Chronic Hepatitis A and B - Kaposi's Sarcoma

13. Digoxin v. Digitoxin: half life?
Digitoxin 168hrs Digoxin 40 hrs
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
physostigmine
Protease inhibitor.

14. Acetazolamide - site of action?
fetal renal toxicity - hyperkalemia
proximal convoluted tubule
DHPG (dihydroxy-2- propoxymethyl guanine)
Acetylcholine esterase

15. Common side effects associated with Clindamycin include?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
RESPIre
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Amphotericin B - Nystatin - Fluconazole/azoles

16. How would you reverse the effect of a neuromuscular blocking agent?
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Give an antichloinesterase - neostigmine - edrophonium - etc
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
Suramin

17. Which Aminoglycoside is used for Bowel Surgery ?
- Chloramphenicol
Neomycin
Inhibits cell wall mucopeptide formation - Bactericidal
Megaloblastic anemia - Leukopenia - Granulocytopenia

18. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
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.
Pseudomonas species and Gram - rods
Modification via Acetylation
Inhibit viral DNA polymerase

19. What is the category of drug names ending in - navir (e.g. Saquinavir)
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Protease inhibitor.
Increases coumadin metabolism
- Alkalinize urine & dialysis

20. Which drug(s) cause this reaction: Torsade de pointes (2)?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Protease inhibitor.

21. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
Dopamine
- Bleomycin - amiodarone - busulfan
Beta - lactam antibiotics
blocks SR Ca2+ channels

22. What is the mechanism of Tacrolimus (FK506)?
Enterobacter
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.

23. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Pseudomonas species and Gram - rods
Chronic Hepatitis A and B - Kaposi's Sarcoma
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
- Nitrate - hydroxocobalamin thiosulfate

24. How would you treat African Trypanosomiasis (sleeping sickness)?
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
- Oral Contraceptives
Suramin
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

25. What is a sign of toxicity with the use of thrombolytics?
Aminoglycosides
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Bleeding.
Ceftriaxone

26. What antimicrobial class is Aztreonam syngergestic with?
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Aminoglycosides
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
- ACE inhibitors (Losartan>no cough)

27. How does dantrolene work?
torsade de pointes - excessive Beta block
- Physostigmine salicylate
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

28. Mannitol - toxicity?
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
GET on the Metro
pulmonary edema - dehydration
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

29. What is the effect of epinephrine infusion on bp and pulse pressure?
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Long.
Does not cross
first dose orthostatic hypotension - dizziness - headache

30. Adverse effects of Clonidine?
Neutropenia
fetal renal toxicity - hyperkalemia
dry mouth - sedation - severe rebound hypertension
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.

31. List the specific antidote for this toxin: Cyanide
- Formaldehyde & formic acid - severe acidosis & retinal damage
- Nitrate - hydroxocobalamin thiosulfate
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Beta1 more than B2

32. What conditions would you use dantrolene?
- Disulfram & also sulfonylureas - metronidazole
Delirium - Tremor - Nephrotoxicity
Pentamidine
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

33. Name three K+ sparing diuretics?
blocks SR Ca2+ channels
Pentamidine
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Rifampin

34. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
Staphlococcus aureus
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
- Fluoroquinolones
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

35. What is the MOA for Ampicillin and Amoxicillin?
hyperaldosteronism - K+ depletion - CHF
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Same as penicillin. Extended spectrum antibiotics
Carbenicillin - Piperacillin - and Ticarcillin

36. Why are the Sulfonylureas inactive in IDDM (type -1)?
Clavulanic acid
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Doxycycline - because it is fecally eliminated
Because they require some residual islet function.

37. What is the MOA for Rifampin?
It inhibits release of NE.
Inhibits DNA dependent RNA polymerase
Albuterol - tertbutaline
Same as penicillin. Act as narrow spectrum antibiotics

38. Which drug(s) cause this reaction: Tardive dyskinesia?
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
- Oral Contraceptives
Blocks Influenza A and RubellA; causes problems with the cerebellA
- Antipsychotics

39. What is the major side effect for Carbenicillin - Piperacillin - and Ticarcillin?
Leukotrienes increasing bronchial tone.
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Hypersensitivity reactions
- Daunorubicin & Doxorubicin

40. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
Dopamine
reversible SLE- like syndrome
Due to the presence of a bulkier R group

41. What is the memory key for Metronidazole's clinical uses?
Gram + - Gram - - Norcardia - Chlamydia
- Niacin - Ca++ channel blockers - adenosine - vancomycin
GET on the Metro
post MI and digitalis induced arrhythmias

42. Which drug(s) cause this reaction: Anaphylaxis?
Impairs the synthesis of vitamin K- dependent clotting factors
- Penicillin
Due to the presence of a bulkier R group
- aminoglycosides - loop diuretics - cisplatin

43. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
all of them
aPTT (intrinsic pathway)
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.

44. MOA: Block peptidoglycan synthesis
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Abortifacient.
Bacitracin - Vancomycin

45. What is the mechanism of action of Allopurinol used to treat chronic gout?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Impairs the synthesis of vitamin K- dependent clotting factors
Inhalational general anesthetic.
Competitive inibitor of progestins at progesterone receptors.

46. What is the MOA for Clindamycin?
Cyclooxygenases (COX I - COX II).
- aminoglycosides - loop diuretics - cisplatin
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic

47. Name the steps in drug approval(4)?
Inhibits CMV DNA polymerase
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)

48. Mannitol - mechanism?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
Digitoxin 168hrs Digoxin 40 hrs
hypertension - angina - arrhythmias

49. For Warfarin What is the Lab value to monitor
PT
Penicillin.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
- N- acetylcystine

50. What effect would atropine have on the preganglionic sympathetic activation of sweat glands? Would this person sweat?
Phenothiazine (neuroleptic - antiemetic).
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia