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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. Is resistant to penicillinase?
Topical and Oral - for Oral Candidiasis (Thrush)
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Imipenem
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

2. What effect would atropine have on a patient with peptic ulcer disease?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
DOC in diagnosing and abolishing AV nodal arrhythmias
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

3. Which diuretics increase urine Ca2+?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Systemic mycoses
loop diuretics - spironolactone

4. What organisms does Griseofulvin target?
Chronic anticoagulation.
Dermatophytes (tinea - ringworm)
Protamine sulfate
Babiturate.

5. What is the category of drug names ending in - cycline (e.g. Tetracycline)
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Antibiotic - protein synthesis inhibitor.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol

6. What is the mechanism of action of the glucocorticoids?
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Praziquantel
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

7. How does Ganciclovir's toxicity relate to that of Acyclovir?
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Ganciclovir is more toxic to host enzymes
Tricyclic antidepressant.

8. Why are the Sulfonylureas inactive in IDDM (type -1)?
Because they require some residual islet function.
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Na/K ATPase

9. Resistance mechanisms for Chloramphenicol
- polymyxins
ACE inhibitor.
Modification via Acetylation
Yes - it does not cross the placenta.

10. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Alpha -1 antagonist
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
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium

11. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
Increases coumadin metabolism
Indomethacin is used to close a patent ductus arteriosus.
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
GET on the Metro

12. What are two toxicities of the Glitazones?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
1. Weight gain 2. Hepatotoxicity (troglitazone)
- Chloramphenicol
RESPIre

13. What is the MOA for the Macrolides?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
1. Pioglitazone 2. Rosiglitazone.
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

14. For Warfarin What is the Site of action
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
- Ammonium Chloride
Liver
Mg = Must go to the bathroom.

15. How is Ganciclovir used clinically?
1. Pioglitazone 2. Rosiglitazone.
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
CMV - esp in Immunocompromised patients
Flecainide - Encainide - Propafenone

16. Ca2+ channel blockers - clinical use?
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
hypertension - angina - arrhythmias
1. Weight gain 2. Hepatotoxicity (troglitazone)
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion

17. What reversal agent could a Anes give to reverse the effects of Atropine
Bethanechol - Neostigmine - physostigmine
Ipratropium
propanolol - esmolol - metoprolol - atenolol - timolol
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

18. List the mechanism - clinical use - & toxicity of Nitrosureas.
- Alkalate DNA - Brain tumors - CNS toxicity
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Sildenafil fills the penis
Pyridoxine (B6) administration

19. Adverse effects of Methyldopa?

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20. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
Chronic gout.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

21. For Heparin What is the Duration of action
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Acute (hours)
Cephalosporins
Erectile dysfunction.

22. Aztreonam is not ________ with penicillins
cross - allergenic
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
local anesthetic. CNS stimulation or depression. CV depression.
- Daunorubicin & Doxorubicin

23. Which RT inhibitor causes Megaloblastic Anemia?
AmOxicillin has greater Oral bioavailability
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
As an anticholinesterase it increases endogenous ACh and thus increases strength.
AZT

24. How is Trimethoprim used clinically?
Beta -2 agonist.
Used in combination therapy with SMZ to sequentially block folate synthesis
Pralidoxime regenerates active cholinesterase.
Mebendazole/Thiabendazole - Pyrantel Pamoate

25. Digitalis - site of action?
Lidocaine - Mexiletine - Tocainide
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Na/K ATPase

26. How do you treat coma in the ER (4)?
anticholinesterase glaucoma
1. Acarbose 2. Miglitol
- Isoniazid
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

27. What antimuscarinic agent is used in asthma and COPD?
cortical collecting tubule
Ipratropium
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Neutropenia

28. MOA: Block nucleotide synthesis
Binding to the presynaptic alpha 2 release modulating receptors
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Sulfonamides - Trimethoprim
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

29. What populations are Floroquinolones contraindicated in? Why?
1. Acarbose 2. Miglitol
Acute gout.
Pregnant women - Children; because animal studies show Damage to Cartilage
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

30. How does angiotensin II affect NE release?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Polymyxins
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
It acts presynaptically to increase NE release.

31. What are four thrombolytics?
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Decreases synthesis of Mycolic Acid
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Erectile dysfunction.

32. What is the definition of zero - order kinetics? Example?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
The only local anesthetic with vasoconstrictive properties.
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

33. Which drug(s) cause this reaction: Gynecomastia (6)?
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Staphlococcus aureus
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

34. Antimicrobial prophylaxis for Gonorrhea
Gemfibrozil - Clofibrate
Ceftriaxone
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Teratogenic - Carcinogenic - Confusion - Headaches

35. How does a competitive antagonist effect an agonist?
Chronic (weeks or months)
- Shifts the curve to the right - increases Km
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
- Atropine & pralidoxime

36. Why would you give a drug like pancuronium or succinylcholine?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
- Protamine
Useful in muscle paralysis during surgery or mechanical ventilation.

37. For Warfarin What is the Duration of action
Chronic (weeks or months)
Methylation of rRNA near Erythromycin's ribosome binding site
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
Oral

38. Triamterene and amiloride - mechanism?
With an amino acid change of D- ala D- ala to D- ala D- lac
block Na+ channels in the cortical collecting tubule
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

39. Mannitol - mechanism?
Increase target cell response to insulin.
- Niacin - Ca++ channel blockers - adenosine - vancomycin
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

40. What are common toxic side effects of Sulfonamides? (5)
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
It affects beta receptors equally and is used in AV heart block (rare).
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

41. What is the major side effect for Carbenicillin - Piperacillin - and Ticarcillin?
Choline acetyltransferase
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Hypersensitivity reactions

42. 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.
anticholinesterase glaucoma
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
- Isoniazid

43. Adverse effects of Clonidine?
dry mouth - sedation - severe rebound hypertension
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
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.

44. Aztreonam is not usually...
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
toxic
- Fluoroquinolones

45. What are two toxicities of the Sulfonylureas?
Nitrates
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Early myocardial infarction.
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

46. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Gemfibrozil - Clofibrate
Inhibit viral DNA polymerase

47. What is a common drug interaction associated with Griseofulvin?
fetal renal toxicity - hyperkalemia
Increases coumadin metabolism
check PFTs - LFTs - and TFTs
Abortifacient.

48. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Sotalol - Ibutilide - Bretylium - Amiodarone
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Keratin containing tissues - e.g. - nails
Pseudomonas species and Gram - rods

49. Digoxin v. Digitoxin: excretion?
Digoxin=urinary Digitoxin=biliary
Liver
Oral
YES

50. What do Aminoglycosides require for uptake?
Oxygen
Scopolamine
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)