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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. Why is carbachol and pilocarpine useful in treatment of glaucoma?
Competitive inibitor of progestins at progesterone receptors.
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Tricyclic antidepressant.

2. What is the clinical use of Tacrolimus (FK506)?
Potent immunosuppressive used in organ transplant recipients.
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Intrathecally
bradycardia - AV block - CHF

3. What is Fluconazole specifically used for?
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

4. What is the definition of zero - order kinetics? Example?
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Potent immunosuppressive used in organ transplant recipients.
Teratogenic - Carcinogenic - Confusion - Headaches
prevention of nodal arrhythmias (SVT)

5. Name some common Sulfonamides (4)
Hypersensitivity reactions
Megaloblastic anemia - Leukopenia - Granulocytopenia
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.

6. What is the category of drug names ending in - pril (e.g. Captopril)
- Hydralazine - Procainamide - INH - phenytoin
- Corticosteroids - heparin
Prophylaxis for Influenza A - Rubella; Parkinson's disease
ACE inhibitor.

7. Describe Phase II metabolism in liver(3)?
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

8. Triamterene and amiloride - mechanism?
block Na+ channels in the cortical collecting tubule
anticholinesterase glaucoma
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Large anionic polymer - acidic

9. What is the category and mechanism of action of Zafirlukast in Asthma treatment?
Antileukotriene; blocks leukotriene receptors.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Pentamidine
ACIDazolamide' causes acidosis

10. Antiarrhythmic class IC- toxicity?
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
proarrhythmic
Hypersensitivity reactions
Antibiotic - protein synthesis inhibitor.

11. Antiarrhythmic class II- toxicity?
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Ceftriaxone
Binding to the presynaptic alpha 2 release modulating receptors

12. Antiarrhythmic class IB- toxicity?
local anesthetic. CNS stimulation or depression. CV depression.
Gram + - Gram - - Norcardia - Chlamydia
Binds ergosterol - Disrupts fungal membranes
Hemolytic anemia

13. What is the mechanism of action of Clomiphene?
Digoxin=urinary Digitoxin=biliary
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
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.
- Isoniazid

14. Quinidine - toxicity?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
first dose orthostatic hypotension - dizziness - headache
- Clindamycin
Staphlococcus aureus

15. Acetazolamide - toxicity?
- Disulfram & also sulfonylureas - metronidazole
cross - allergenic
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
It must be Phosphorylated by Viral Thymidine Kinase

16. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
viral kinase
Penicillin.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Hydralazine and Minoxidil

17. Antimicrobial prophylaxis for Syphilis
- B51Naloxone / naltrexone (Narcan)
Benzathine penicillin G
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Protease Inhibitors and Reverse Transcriptase Inhibitors

18. Furosemide increases the excretion of What ion?
all of them
Ca2+ (Loops Lose calcium)
decrease
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.

19. List the specific antidote for this toxin: Iron
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Pretreat with antihistamines and a slow infusion rate
- Deferoxamine
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

20. What is the clinical utility of cocaine?
Treatment of infertility.
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.)
prevention of nodal arrhythmias (SVT)
The only local anesthetic with vasoconstrictive properties.

21. K+ sparing diuretics - site of action?
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
- Chlorpromazine - thioridazine - haloperidol
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.
cortical collecting tubule

22. How does NE modulate its own release? What other neurotransmitter has this same effect?
Beta1 more than B2
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
bradycardia - AV block - CHF
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.

23. What are four thrombolytics?
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
- NaHCO3
1. Weight gain 2. Hepatotoxicity (troglitazone)

24. What Sulfonamides are used for simple UTIs?
new arrhythmias - hypotension
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Triple sulfas or SMZ
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

25. What conditions would you use dantrolene?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
first dose orthostatic hypotension - dizziness - headache

26. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Penicillin.
Ganciclovir is more toxic to host enzymes
Minor hepatotoxicity - Drug interactions (activates P450)

27. Cocaine casues vasoconstriction and local anesthesia by What mechanism
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Indirect agonist - uptake inhibitor
Cyclooxygenases (COX I - COX II).
Foscarnet = pyroFosphate analog

28. What is the memory key for the action of Sildenafil (Viagra)?
Sildenafil fills the penis
Pretreat with antihistamines and a slow infusion rate
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Dopamine

29. What is used to reverse the action of Heparin?
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
- Vinca alkaloids(inhibit MT) - Paclitaxel
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
torsade de pointes - excessive Beta block

30. What is the mecanism of action of Sucralfate?
1. Acarbose 2. Miglitol
Inhibt Assembly of new virus by Blocking Protease Enzyme
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.
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes

31. What is the MOA for Metronidazole?
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
BM suppression (neutropenia - anemia) - Peripheral neuropathy
effective in torsade de pointes and digoxin toxicity
Forms toxic metabolites in the bacterial cell - Bactericidal

32. What are four advantages of newer low - molecular - weight heparins (Enoxaparin)?
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Megaloblastic anemia - Leukopenia - Granulocytopenia
Pretreat with antihistamines and a slow infusion rate
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

33. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Aminoglycosides
Constant FRACTION eliminated per unit time.(exponential)
Beta - lactam antibiotics
Pseudomonas species and Gram - rods

34. What is the memory aid for subunit distribution of ribosomal inhibitors?

35. What is the memory key to remember Which pathway (extrinsic vs. intrinsic) and Which lab value Warfarin affects?
Decreases synthesis of Mycolic Acid
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

36. For Warfarin What is the Onset of action
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Slow - limited by half lives of clotting factors
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Phosphorylation by a Viral Kinase

37. Name three Antiarrhythmic drugs in class IC.
Acetylcholine esterase
Flecainide - Encainide - Propafenone
AZT
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

38. Are not penicillinase resistant
Carbenicillin - Piperacillin - and Ticarcillin
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.
Butyrophenone (neuroleptic).
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

39. Which cancer drugs inhibit nucleotide synthesis(3)?
Ceftriaxone
- Methotrexate - 5 FU - 6 mercaptopurine
1. Weight gain 2. Hepatotoxicity (troglitazone)
Sulfonamides - Trimethoprim

40. Guanethidine enhances the release of Norepi?
Pretreat with antihistamines and a slow infusion rate
No - it inhibits the release of Nor Epi
Delirium - Tremor - Nephrotoxicity
Same as penicillin. Extended spectrum antibiotics

41. What antimuscarinic agent is used in asthma and COPD?
first dose orthostatic hypotension - dizziness - headache
Inhibits cell wall mucopeptide formation - Bactericidal
Ipratropium
Beta -2 agonist.

42. What are two clinical uses of Azathioprine?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Triple sulfas or SMZ
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)

43. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Choline acetyltransferase
Disulfiram - like reaction with EtOH - Headache
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Same as penicillin. Extended spectrum antibiotics

44. What is the clinical use of Mifepristone (RU486)?
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Abortifacient.

45. What is the MOA of Griseofulvin?
- Antipsychotics
CMV - esp in Immunocompromised patients
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Interferes with microtubule function - disrupts mitosis - inhibits growth

46. Ibutilide - toxicity?
Interstitial nephritis
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
depresses ectopic pacemakers - especially in digoxin toxicity
torsade de pointes

47. What is Metronidazole used for clinically?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
1. Acarbose 2. Miglitol
Teratogenic - Carcinogenic - Confusion - Headaches
proximal convoluted tubule - thin descending limb - and collecting duct

48. What should not be taken with Tetracyclines? / Why?
- Isoniazid
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Early myocardial infarction.
Same as penicillin. Extended spectrum antibiotics

49. Which drug(s) cause this reaction: Hot flashes?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
- Tamoxifen
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Lidocaine - Mexiletine - Tocainide

50. What are toxic side effects for Metronidazole?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Disulfiram - like reaction with EtOH - Headache
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor