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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. Spironolactone - mechanism?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Those patients who are taking nitrates.
competitive inhibirot of aldosterone in the cortical collecting tubule
Vd= (Amt. of drug in body/ Plasma drug conc.)

2. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Dopamine; causes its release from intact nerve terminals
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Cell membrane Ca2+ channels of cardiac sarcomere
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

3. What is the MOA for the Azoles?
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Haloperidol - chlorpromazine - reserpine - MPTP
Inhibit Ergosterol synthesis

4. Antiarrhythmic class IV- primary site of action?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
physostigmine
Tricyclic antidepressant.
AV nodal cells

5. Which Tetracycline is used in patients with renal failure? / Why?
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Sildenafil fills the penis
Doxycycline - because it is fecally eliminated
Diuresis in pateints with sulfa allergy

6. Adverse effects of Minoxidil?
Interferes with microtubule function - disrupts mitosis - inhibits growth
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Saquinavir - Ritonavir - Indinavir - Nelfinavir
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

7. Which drug(s) cause this reaction: Hepatitis?
No - warfarin - unlike heparin - can cross the placenta.
Abortifacient.
first dose orthostatic hypotension - dizziness - headache
- Isoniazid

8. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Ca2+ (Loops Lose calcium)
Pseudomonas species and Gram - rods
GI disturbances.

9. Clinical use of Isoniazid (INH)?
Yes
Succinylcholine
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
local anesthetic. CNS stimulation or depression. CV depression.

10. Ca2+ channel blockers - mechanism?
Cardiac glycoside (inotropic agent).
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
- Glucocorticoid withdrawal
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

11. List the specific antidote for this toxin: Methanol & Ethylene glycol
Leukotrienes increasing bronchial tone.
- Ethanol - dialysis - & fomepizole
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Rare.

12. What are the clinical indications for Azole therapy?
Vd= (Amt. of drug in body/ Plasma drug conc.)
Systemic mycoses
thiazides - amiloride
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

13. Name three ACE inhibitors?
Beta lactams - inhibit cell wall synthesis - Bactericidal
The only local anesthetic with vasoconstrictive properties.
Captopril - Enalapril - Lisinopril
- Clindamycin

14. What is the MOA of Isoniazid (INH)?
Keratin containing tissues - e.g. - nails
Decreases synthesis of Mycolic Acid
Antileukotriene; blocks synthesis by lipoxygenase.
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

15. K+ sparing diuretics - toxicity?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
AZT - to reduce risk of Fetal Transmission
PT

16. How is Amphotericin B administered for fungal meningitis?
Give an antichloinesterase - neostigmine - edrophonium - etc
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Intrathecally
Neomycin

17. List the specific antidote for this toxin: Tricyclic antidepressants
AZT - to reduce risk of Fetal Transmission
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
- NaHCO3
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

18. What can result due to antacid overuse?
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
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.
Cyclooxygenases (COX I - COX II).

19. What is the mechanism of Leuprolide?
GnRH analog with agonist properties When used in pulsatile fashion and antagonist properties When used in continuous fashion - causing a transient initial burst of LH and FSH
- Quinidine - quinine
With an amino acid change of D- ala D- ala to D- ala D- lac
Succinylcholine

20. Adverse effects of Loop Diuretics?
GET on the Metro
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Epinephirine(Alpha1 -2 and Beta 1 -2)
Methicillin - Nafcillin - and Dicloxacillin

21. What are four thrombolytics?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Pregnant women - Children; because animal studies show Damage to Cartilage
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
torsade de pointes

22. How are the HIV drugs used clinically?

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23. Antimicrobial prophylaxis for a history of recurrent UTIs
dry mouth - sedation - severe rebound hypertension
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
TMP- SMZ
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

24. Which drug(s) cause this reaction: Gingival hyperplasia?
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.
- Phenytoin
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
The only local anesthetic with vasoconstrictive properties.

25. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Protamine sulfate
- Tamoxifen
Penicillin.
It acts presynaptically to increase NE release.

26. What are the clinical uses for Imipenem/cilastatin?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Gram + cocci - Gram - rods - and Anerobes
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Small lipid - soluble molecule

27. What microorganisms is Aztreonam not effective against?
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Gram + and Anerobes
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
AmOxicillin has greater Oral bioavailability

28. For Warfarin What is the Mechanism of action
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Pseudomonas species and Gram - rods
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Impairs the synthesis of vitamin K- dependent clotting factors

29. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
GI side effects. (Indomethacin is less toxic - more commonly used.)
Ataxia - Dizziness - Slurred speech

30. Which cancer drugs work at the level of proteins(2)?
Verapamil - Diltiazem - Bepridil
- Vinca alkaloids(inhibit MT) - Paclitaxel
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Forms toxic metabolites in the bacterial cell - Bactericidal

31. Hydralazine - class and mechanism?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
fetal renal toxicity - hyperkalemia
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

32. What is the mechanism of action of Probenacid used to treat chronic gout?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Inhibits reabsorption of uric acid.
Indirect agonist - uptake inhibitor

33. What are three common NSAIDS other than Aspirin?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Lipoxygenase
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Ibuprofen - Naproxen - and Indomethacin

34. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
- Tetracycline - amiodarone - sulfonamides
TCA
It affects beta receptors equally and is used in AV heart block (rare).
Rare.

35. List the specific antidote for this toxin: Heparin
Chronic gout.
check PFTs - LFTs - and TFTs
- Protamine
Impairs the synthesis of vitamin K- dependent clotting factors

36. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
- Atropine & pralidoxime
- Bleomycin - amiodarone - busulfan
Dopamine

37. Furosemide - clinical use?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Pyridoxine (B6) administration

38. List the specific antidote for this toxin: Amphetamine
- Ammonium Chloride
- Alkalate DNA - Brain tumors - CNS toxicity
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
It inhibits release of NE.

39. What organisms does Griseofulvin target?
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Dermatophytes (tinea - ringworm)

40. Acetazolamide causes?

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41. What is the definition of zero - order kinetics? Example?
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Ipratropium
- Ethanol - dialysis - & fomepizole
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

42. The MOA for Chloramphenicol is?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Inhibition of 50S peptidyl transferase - Bacteriostatic
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Long.

43. What is the MOA for the Macrolides?
It inhibits release of NE.
Lipoxygenase
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Quinidine - Amiodarone - Procainamide - Disopyramide

44. Which diuretics decrease urine Ca2+?
DHPG (dihydroxy-2- propoxymethyl guanine)
thiazides - amiloride
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
-100% oxygen - hyperbaric

45. What do you treat Nematode/roundworm (pinworm - whipworm) infections with?
Mebendazole/Thiabendazole - Pyrantel Pamoate
hyperaldosteronism - K+ depletion - CHF
CL= (rate of elimination of drug/ Plasma drug conc.)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

46. ACE inhibitors - toxicity?
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
edrophonium (extremely short acting anticholinesterase)
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

47. IV Penicillin
amphetamine and ephedrine
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
Penicillin - G
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

48. Adverse effects of Prazosin?
Teratogenic - Carcinogenic - Confusion - Headaches
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
first dose orthostatic hypotension - dizziness - headache
carbonic anhydrase inhibitors - K+ sparing diuretics

49. Name three calcium channel blockers?
- NaHCO3
Nifedipine - Verapamil - Diltiazem
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

50. MOA: Block peptidoglycan synthesis
Useful in muscle paralysis during surgery or mechanical ventilation.
Babiturate.
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.
Bacitracin - Vancomycin