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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. MOA of Succinylcholine
Liver
Prevents the release of Ca from SR of skeletal muscle
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
- Niacin - Ca++ channel blockers - adenosine - vancomycin

2. Ethacrynic Acid - clinical use?
Quinolones
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.
Diuresis in pateints with sulfa allergy
- Deferoxamine

3. Dobutamine used for the tx of shock acts on Which receptors
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
ACIDazolamide' causes acidosis
Beta1 more than B2
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate

4. MOA: Block mRNA synthesis
Peptic ulcer disease.
depresses ectopic pacemakers - especially in digoxin toxicity
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Rifampin

5. Adenosine - clinical use?
Choline acetyltransferase
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
DOC in diagnosing and abolishing AV nodal arrhythmias
Chronic gout.

6. List the specific antidote for this toxin: Cyanide
Babiturate.
- Nitrate - hydroxocobalamin thiosulfate
- Steroids - Tamoxifen
Bleeding.

7. For Warfarin What is the Onset of action
sedation - depression - nasal stuffiness - diarrhea
It acts presynaptically to increase NE release.
Slow - limited by half lives of clotting factors
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

8. What is the memory key for Isoniazid (INH) toxicity?
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
INH: Injures Neurons and Hepatocytes
Pentamidine
- Flumazenil

9. Name two bile acid resins.
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Enterobacter
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.
cholestyramine - colestipol

10. What is the memory key for the effect of magnesium hydroxide overuse?
Ipratropium
Systemic mycoses
Beta1 more than B2
Mg = Must go to the bathroom.

11. Mannitol - toxicity?
IV vitamin K and fresh frozen plasma
pulmonary edema - dehydration
Beta -2 agonist.
Delirium - Tremor - Nephrotoxicity

12. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
- ACE inhibitors (Losartan>no cough)
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Tricyclic antidepressant.
Rifampin

13. Which drug(s) cause this reaction: Cutaneous flushing (4)?
Prevents the release of Ca from SR of skeletal muscle
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Protease inhibitor.

14. For Warfarin What is the Site of action
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Methicillin - Nafcillin - and Dicloxacillin
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.
Liver

15. Aztreonam ________ to penicillinase
Pituitary hormone.
is resistant
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

16. What would be the effect on blood pressure with infusion of the alpha -2 agonist clonidine?
- Corticosteroids - heparin
Digoxin=urinary Digitoxin=biliary
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
- Haloperidol - chlorpromazine - reserpine - MPTP

17. How does a competitive antagonist effect an agonist?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
- Shifts the curve to the right - increases Km
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Dopamine; causes its release from intact nerve terminals

18. What is a sign of toxicity with the use of thrombolytics?
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Bleeding.
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
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

19. Toxic side effects of the Azoles?
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
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.

20. What are common toxicities associated with Tetracyclines?

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21. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Interstitial nephritis
Hypersensitivity reactions

22. What is the loading dose formula?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
troponin - tropomyosin system
NO
Phenothiazine (neuroleptic - antiemetic).

23. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
Beta - lactam antibiotics
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Sotalol - Ibutilide - Bretylium - Amiodarone
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

24. What are three possible complications of Heparin therapy?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Modification via Acetylation - Adenylation - or Phosphorylation
- Isoniazid
Pralidoxime regenerates active cholinesterase.

25. Which diuretics cause alkalosis?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
loop diuretics - thiazides
- Methylene blue
Chronic anticoagulation.

26. Which drug(s) cause this reaction: Osteoporosis (2)?
- Corticosteroids - heparin
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
- aminoglycosides - loop diuretics - cisplatin
Only in limited amounts

27. What are five possible toxic effects of Aspirin therapy?

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28. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Penicillin.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

29. What type of patient should not take Misoprostol and why?
H2 antagonist
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness

30. What is the category of drug names ending in - terol (e.g. Albuterol)
Beta -2 agonist.
- Deferoxamine
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Oral

31. Thiazides - site of action?
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
GI distress - Skin rash - and Seizures at high plasma levels
It must be Phosphorylated by Viral Thymidine Kinase
distal convoluted tubule (early)

32. List the specific antidote for this toxin: Copper
Sulfonamides - Trimethoprim
cyanide toxicity (releases CN)
Beta adrenergic receptors and Ca2+ channels (stimulatory)
- Penicillamine

33. How is Amantadine used clinically?

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34. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
Succinylcholine
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
thick ascending limb
loop diuretics - spironolactone

35. Which drug(s) cause this reaction: Cinchonism (2)?
- Chloramphenicol
cortical collecting tubule
- Quinidine - quinine
hypertension - CHF - diabetic renal disease

36. MOA: Block DNA topoisomerases
Pregnant women - Children; because animal studies show Damage to Cartilage
Quinolones
Anaerobes
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

37. What is the mechanism of action of Ticlopidine - Clopidogrel
Lidocaine - Mexiletine - Tocainide
reversible SLE- like syndrome
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

38. Name two LPL stimulators.
GET on the Metro
Gemfibrozil - Clofibrate
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Penicillin - V

39. Which drug(s) cause this reaction: Pseudomembranous colitis?
- Clindamycin
AluMINIMUM amount of feces.
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Oral

40. What is the clinical use for Warfarin?
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
- Shifts the curve to the right - increases Km
cholestyramine - colestipol
Chronic anticoagulation.

41. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
Early myocardial infarction.
No
Babiturate.
IV vitamin K and fresh frozen plasma

42. Antimicrobial prophylaxis for Gonorrhea
Ceftriaxone
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
- Ethanol - dialysis - & fomepizole
proarrhythmic

43. What is the major toxic side effect of Penicillin?
Hypersensitivity reactions
Prevents the release of Ca from SR of skeletal muscle
- Formaldehyde & formic acid - severe acidosis & retinal damage
depresses ectopic pacemakers - especially in digoxin toxicity

44. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
Malaria (P. falciparum)
TMP- SMZ (DOC) - aerosolized pentamidine
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

45. What is Imipenem always administered with?
Alpha -1 antagonist
Cardiac glycoside (inotropic agent).
Cilastatin
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes

46. Aztreonam is not ________ with penicillins
- Daunorubicin & Doxorubicin
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
cross - allergenic
Prophylaxis for Influenza A - Rubella; Parkinson's disease

47. For Heparin What is the Site of action
Those patients who are taking nitrates.
Blood
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
cortical collecting tubule

48. What is used to reverse the action of Heparin?
ACIDazolamide' causes acidosis
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
- ACE inhibitors (Losartan>no cough)
Increases coumadin metabolism

49. For Heparin What is the Onset of action
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
BM suppression (neutropenia - anemia) - Peripheral neuropathy
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Rapid (seconds)

50. Toxicities associated with Acyclovir?
Delirium - Tremor - Nephrotoxicity
Rash - Pseudomembranous colitis
Imipenem
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.