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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.
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. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
- Haloperidol - chlorpromazine - reserpine - MPTP
- Aminocaproic acid
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

2. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
- Daunorubicin & Doxorubicin
Penicillin.
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Beta Blockers

3. Resistance mechanisms for Macrolides

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4. Digoxin v. Digitoxin: bioavailability?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Captopril - Enalapril - Lisinopril
Digitoxin>95% Digoxin 75%
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid

5. Acetazolamide causes?

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6. Why does atropine dilate the pupil?
GI side effects. (Indomethacin is less toxic - more commonly used.)
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Severe Gram - rod infections.
cortical collecting tubule

7. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Hypersensitivity reactions
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Epinephirine(Alpha1 -2 and Beta 1 -2)
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

8. Antiarrhythmic class IB- toxicity?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Gemfibrozil - Clofibrate
local anesthetic. CNS stimulation or depression. CV depression.

9. Are Ampicillin and Amoxicillin are not...
Protease Inhibitors and Reverse Transcriptase Inhibitors
- Oxalic acid - Acidosis & nephrotoxicity
penicillinase resistant
Aminoglycosides - Tetracyclines

10. Hydralazine - class and mechanism?
Captopril - Enalapril - Lisinopril
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
- Penicillin

11. What are the clinical uses for Aztreonam?
Systemic mycoses
Antifungal.
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Amphotericin B - Nystatin - Fluconazole/azoles

12. Antiarrhythmic class IV- toxicity?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Cell membrane Ca2+ channels of cardiac sarcomere
Acute (hours)
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

13. What are three clinical uses of the Leuprolide?
Neutropenia
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
- Ammonium Chloride
Pentamidine

14. What enzyme is responsible for the degredation of Ach
Non - Nucleosides
- Quinidine - quinine
Acetylcholine esterase
Digitoxin 168hrs Digoxin 40 hrs

15. How is Rifampin used clinically?
Blocks Norepi - but not Dopamine
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
- Chloramphenicol
- Tetracycline - amiodarone - sulfonamides

16. List the mechanism - clinical use - & toxicity of Nitrosureas.
Na/K ATPase
- Alkalate DNA - Brain tumors - CNS toxicity
Tricyclic antidepressant.
Neutropenia

17. What are are the Sulfonylureas (general description) and What is their use?
YES
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
- Act on same receptor - Full has greater efficacy

18. Which drug(s) cause this reaction: P450 inhibition(6)?
is resistant
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

19. List the specific antidote for this toxin: Copper
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
- Penicillamine
Treatment of infertility.
- Flumazenil

20. Which of epi - norepi - or isoproterenol results in bradycardia?
Norepinephrine
AluMINIMUM amount of feces.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Chronic gout.

21. What are the nondepolarizing neuromuscular blocking drugs?
Prevents the release of Ca from SR of skeletal muscle
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
atropine - homatropine - tropicamide
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

22. Ethacrynic Acid - clinical use?
Diuresis in pateints with sulfa allergy
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
TMP- SMZ
Digitoxin>95% Digoxin 75%

23. What are four thrombolytics?
Pentamidine
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)

24. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Binding to the presynaptic alpha 2 release modulating receptors

25. What is the major side effect for Ampicillin and Amoxicillin?
Hypersensitivity reactions
- Shifts the curve down - reduces Vmax
Aplastic anemia (dose independent) - Gray Baby Syndrome
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

26. Amprotericin B ___________ the BBB
Does not cross
carbonic anhydrase inhibitors - K+ sparing diuretics
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Early myocardial infarction.

27. What is the category of drug names ending in - ane (e.g. Halothane)
Inhalational general anesthetic.
Prevents the release of ACh - Which results in muscle paralysis.
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

28. List the specific antidote for this toxin: Benzodiazepines
Does not cross
Protease inhibitor.
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
- Flumazenil

29. MOA: Disrupt fungal cell membranes
It affects beta receptors equally and is used in AV heart block (rare).
Amphotericin B - Nystatin - Fluconazole/azoles
Pseudomembranous colitis (C. difficile) - fever - diarrhea
for RSV

30. What is the formula for Volume of distribution (Vd)
Benzathine penicillin G
Vd= (Amt. of drug in body/ Plasma drug conc.)
The only local anesthetic with vasoconstrictive properties.
Inhibits DNA dependent RNA polymerase

31. For Warfarin What is the Lab value to monitor
all of them
PT
decrease
Polymyxins

32. List the specific antidote for this toxin: Salicylates
- Lithium
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
- Alkalinize urine & dialysis
Minor hepatotoxicity - Drug interactions (activates P450)

33. Describe Phase I metabolism in liver(3)?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Ca2+ (Loops Lose calcium)
Aminoglycosides
- Quinidine - quinine

34. How is Chloramphenical used clinically?
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
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.)
Fast vs. Slow Acetylators
bradycardia - AV block - CHF

35. K+- clinical use?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
BM suppression (neutropenia - anemia) - Peripheral neuropathy
depresses ectopic pacemakers - especially in digoxin toxicity
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

36. For Heparin What is the Mechanism of action
With an amino acid change of D- ala D- ala to D- ala D- lac
Activates antithrombin III
Hydralazine and Minoxidil
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

37. Toxic effects of TMP include?
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Megaloblastic anemia - Leukopenia - Granulocytopenia
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Lithium

38. For Warfarin What is the Ability to inhibit coagulation in vitro
Inhibition of 50S peptidyl transferase - Bacteriostatic
No
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
- Hydralazine - Procainamide - INH - phenytoin

39. What is the clinical utility of cocaine?
The only local anesthetic with vasoconstrictive properties.
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Pentavalent Antimony
block Na+ channels in the cortical collecting tubule

40. What are toxic side effects for Metronidazole?
Disulfiram - like reaction with EtOH - Headache
Interferes with microtubule function - disrupts mitosis - inhibits growth
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
- Ethosuxamide - sulfonamides - lamotrigine

41. What is the MOA for Vancomycin?
Flecainide - Encainide - Propafenone
Severe Gram - rod infections.
Inhibits cell wall mucopeptide formation - Bactericidal
Triple sulfas or SMZ

42. What type of gout is treated with Allopurinol?
Chronic gout.
Benzodiazepine.
These B-2 agonists cause respiratory smooth muscle to relax.
Rare.

43. What can result due to antacid overuse?
Alpha -1 antagonist
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

44. Oral Penicillin
first dose orthostatic hypotension - dizziness - headache
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
very short acting
Penicillin - V

45. Foscarnet does not require activation by a...
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
torsade de pointes
viral kinase
Beta lactams - inhibit cell wall synthesis - Bactericidal

46. Classes of antihypertensive drugs?
AV nodal cells
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

47. Which drug(s) cause this reaction: Cardiac toxicity?
PT
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Inhibits reabsorption of uric acid.
- Daunorubicin & Doxorubicin

48. Which drug(s) cause this reaction: Aplastic anemia (5)?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Primaquine
dizziness - flushing - constipation (verapamil) - nausea
- Chlorpromazine - thioridazine - haloperidol

49. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
It must be Phosphorylated by Viral Thymidine Kinase
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Cyclooxygenases (COX I - COX II).
Due to the presence of a bulkier R group

50. How do we stop angina?
Indomethacin is used to close a patent ductus arteriosus.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Useful in muscle paralysis during surgery or mechanical ventilation.
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time