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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. What are signs of Sildenafil (Viagra) toxicity?
Headache - flushing - dyspepsia - blue - green color vision.
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Spironolactone - Triamterene - Amiloride (the K+ STAys)

2. Why does NE result in bradycardia?
Beta Blockers
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

3. What effect would atropine have on the preganglionic sympathetic activation of sweat glands? Would this person sweat?
Pretreat with antihistamines and a slow infusion rate
Penicillin.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Yes

4. Which drug(s) cause this reaction: Thrombotic complications?
Penicillin.
- Oral Contraceptives
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

5. What type of patient should not take Misoprostol and why?
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Norepinephrine (Alpha1 -2 and beta 1)
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)

6. How do spare receptors effect the Km?
- ED 50 is less than the Km (less than 50% of receptors)
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Inhibits CMV DNA polymerase
Primaquine

7. Can Heparin be used during pregnancy?
Digitoxin>95% Digoxin 75%
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Norepinephrine (Alpha1 -2 and beta 1)
Yes - it does not cross the placenta.

8. What is the memory key for Metronidazole's clinical uses?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
GET on the Metro
Protease inhibitor.
Pralidoxime regenerates active cholinesterase.

9. Antiarrhythmic class IB- effects?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
- Normalize K+ - Lidocaine - & Anti - dig Mab
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.

10. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
first dose orthostatic hypotension - dizziness - headache
Ceftriaxone
Blocks Norepi - but not Dopamine
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

11. List the mechanism - clinical use - & toxicity of Paclitaxel.
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Foscarnet = pyroFosphate analog
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- Hydralazine - Procainamide - INH - phenytoin

12. Foscarnet does not require activation by a...
physostigmine
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Intrathecally
viral kinase

13. Antiarrhythmic Class III- effects?
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Tendonitis and Tendon rupture

14. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Tricyclic antidepressant.
is resistant
Local anesthetic.

15. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Beta adrenergic receptors and Ca2+ channels (stimulatory)
- Ethanol - dialysis - & fomepizole

16. Which drug(s) cause this reaction: Hepatitis?
Butyrophenone (neuroleptic).
BM suppression (neutropenia - anemia) - Peripheral neuropathy
- Isoniazid
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

17. Which drug(s) cause this reaction: Anaphylaxis?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Constant FRACTION eliminated per unit time.(exponential)
- Penicillin
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

18. What conditions would you use dantrolene?
- Penicillin
decrease conduction velocity - increase ERP - increase PR interval
post MI and digitalis induced arrhythmias
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

19. What is Ketoconazole specifically used for?
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.
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Praziquantel

20. What are four H2 Blockers?
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
- Tricyclic antidepressants

21. When is Rifampin not used in combination with other drugs?
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Ataxia - Dizziness - Slurred speech

22. How is Griseofulvin used clinically?
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
troponin - tropomyosin system
Oral treatment of superficial infections
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

23. How can Isoniazid (INH)- induced neurotoxicity be prevented?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Gemfibrozil - Clofibrate
Pentamidine
Pyridoxine (B6) administration

24. Hydrochlorothiazide - mechanism?
torsade de pointes - excessive Beta block
Blood
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
troponin - tropomyosin system

25. Antiarrhythmic class IC- toxicity?
proarrhythmic
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Inhibit viral DNA polymerase
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

26. List the mechanism - clinical use - & toxicity of 5 FU.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Prevents the release of Ca from SR of skeletal muscle
cross - allergenic
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

27. What is the MOA for the Tetracyclines?
Neutropenia
Pregnant women - Children; because animal studies show Damage to Cartilage
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

28. What microorganisms are Aminoglycosides ineffective against?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- Protamine
Anaerobes
- Shifts the curve to the right - increases Km

29. MOA: Block nucleotide synthesis
Sulfonamides - Trimethoprim
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.)
Nevirapine - Delavirdine
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone

30. Which Aminoglycoside is used for Bowel Surgery ?
It affects beta receptors equally and is used in AV heart block (rare).
Neomycin
Acetylcholinesterase; ACh is broken down into choline and acetate.
Nevirapine - Delavirdine

31. What is the memory key for the effect of aluminum hydroxide overuse?
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Gemfibrozil - Clofibrate
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
AluMINIMUM amount of feces.

32. List the specific antidote for this toxin: Amphetamine
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Liver
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- Ammonium Chloride

33. Classes of antihypertensive drugs?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Onchocerciasis ('river blindness'-- rIVER- mectin)
viral kinase
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

34. Preferential action of the Ca2+ channel blockers at cardiac muscle?
Phenothiazine (neuroleptic - antiemetic).
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
cardiac muscle: Verapamil>Diltiazem>Nifedipine
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

35. How is Rifampin used clinically?
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Lipoxygenase
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
cardiac muscle: Verapamil>Diltiazem>Nifedipine

36. What is the MOA for Vancomycin?
Inhibits cell wall mucopeptide formation - Bactericidal
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Headache - flushing - dyspepsia - blue - green color vision.
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

37. What is the clinical utility of cocaine?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
The only local anesthetic with vasoconstrictive properties.
Enterobacter

38. What is the mechanism of action of Acetaminophen?
1. Pioglitazone 2. Rosiglitazone.
Beta antagonist.
collecting ducts
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

39. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
- Tetracycline
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
ACIDazolamide' causes acidosis

40. Which diuretics cause alkalosis?
blocks SR Ca2+ channels
loop diuretics - thiazides
Those patients who are taking nitrates.
With an amino acid change of D- ala D- ala to D- ala D- lac

41. Bretyllium - toxicity?
new arrhythmias - hypotension
sedation - positive Coombs' test
Ipratropium
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

42. For Warfarin What is the Duration of action
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Pyridoxine (B6) administration
Chronic (weeks or months)

43. What are Polymyxins used for?
- Atropine & pralidoxime
Resistant Gram - infections
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
is resistant

44. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Give an antichloinesterase - neostigmine - edrophonium - etc
Blocks Influenza A and RubellA; causes problems with the cerebellA

45. What are three common NSAIDS other than Aspirin?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Acetylcholinesterase; ACh is broken down into choline and acetate.
Ibuprofen - Naproxen - and Indomethacin
- Methotrexate - 5 FU - 6 mercaptopurine

46. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Chronic Hepatitis A and B - Kaposi's Sarcoma

47. MOA: Bactericidal antibiotics
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Rheumatoid and osteoarthritis.
Carbachol - pilocarpine - physostigmine - echothiophate
Antileukotriene; blocks synthesis by lipoxygenase.

48. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Teratogenic - Carcinogenic - Confusion - Headaches
Binding to the presynaptic alpha 2 release modulating receptors
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
These B-2 agonists cause respiratory smooth muscle to relax.

49. What would be the effect on blood pressure with infusion of the alpha -2 agonist clonidine?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
competitive inhibirot of aldosterone in the cortical collecting tubule
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Amphetamine and Ephedrine

50. What is the chemical name for Ganciclovir?
DHPG (dihydroxy-2- propoxymethyl guanine)
Reversible block of histamine H2 receptors
1. Antiandrogen 2. Nausea 3. Vomiting
sedation - positive Coombs' test