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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. Are not penicillinase resistant
Carbenicillin - Piperacillin - and Ticarcillin
Beta antagonist.
Systemic mycoses
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

2. What beta 2 agonist will help your 21yo Astma pt?
thick ascending limb
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Albuterol - tertbutaline
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

3. What is the MOA of Aztreonam?
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
VACUUM your Bed Room'
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

4. What is combination TMP- SMZ used to treat?
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
YES
H2 antagonist
- polymyxins

5. What is the mechanism of action of Misoprostol?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Aminoglycosides
Mg = Must go to the bathroom.
- Chlorpromazine - thioridazine - haloperidol

6. What is the clinical utility of clonidine?
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
- Steroids - Tamoxifen
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

7. How does resistance to Vancomycin occur?
Penicillin.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
With an amino acid change of D- ala D- ala to D- ala D- lac
pulmonary edema - dehydration

8. What are two indirect acting adrenergic agonists?
amphetamine and ephedrine
Nitrates
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
- Deferoxamine

9. Foscarnet does not require activation by a...
Ipratropium
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.
viral kinase
- Niacin - Ca++ channel blockers - adenosine - vancomycin

10. What type of patient should not take Misoprostol and why?
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Pretreat with antihistamines and a slow infusion rate
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

11. List the mechanism - clinical use - & toxicity of Cisplatin.
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Erectile dysfunction.
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
Saquinavir - Ritonavir - Indinavir - Nelfinavir

12. Explain potency in relation to full and partial agonists(2).
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Prevents the release of Ca from SR of skeletal muscle
penicillinase resistant
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

13. MOA: Block peptidoglycan synthesis
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
- Disulfram & also sulfonylureas - metronidazole
Bacitracin - Vancomycin

14. For Warfarin What is the Onset of action
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
cyanide toxicity (releases CN)
Slow - limited by half lives of clotting factors
- Protamine

15. What are four clinical activities of Aspirin?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Chronic gout.
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

16. Why does NE result in bradycardia?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
carbonic anhydrase inhibitors - K+ sparing diuretics
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
cyanide toxicity (releases CN)

17. List the specific antidote for this toxin: TPA & Streptokinase
- Aminocaproic acid
- Methylene blue
Onchocerciasis ('river blindness'-- rIVER- mectin)
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions

18. How is Ganciclovir activated?
Foscarnet = pyroFosphate analog
Phosphorylation by a Viral Kinase
Ibuprofen - Naproxen - and Indomethacin
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

19. What is the clinical use for Sildenafil (Viagra)?
Erectile dysfunction.
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Pituitary hormone.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin

20. How does NE modulate its own release? What other neurotransmitter has this same effect?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
It must be Phosphorylated by Viral Thymidine Kinase
Gram + and Anerobes
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

21. How can the toxic effects of TMP be ameliorated?
With an amino acid change of D- ala D- ala to D- ala D- lac
Penicillin - V
With supplemental Folic Acid
sedation - sleep alterations

22. What is the clinical use for Heparin?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
- Normalize K+ - Lidocaine - & Anti - dig Mab
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

23. How do Sulfonamides act on bacteria?
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Paranteral (IV - SC)
Beta antagonist.
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

24. What are common toxicities associated with Macrolides? (4)
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

25. Why is Cilastatin administered with Imipenem?
Onchocerciasis ('river blindness'-- rIVER- mectin)
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Antibiotic - protein synthesis inhibitor.

26. For Heparin What is the Duration of action
Acute (hours)
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Short.

27. Decrease Digitoxin dose in renal failure?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Sulfonamides - Trimethoprim
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
NO

28. List the specific antidote for this toxin: Methemoglobin
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- NaHCO3
Amphotericin B - Nystatin - Fluconazole/azoles
- Methylene blue

29. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

30. Is resistant to penicillinase?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Inhibits cell wall mucopeptide formation - Bactericidal
Oral
Imipenem

31. What is Nifurtimox administered for?

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32. What are Aminoglycosides synergistic with?
Beta - lactam antibiotics
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
AmOxicillin has greater Oral bioavailability
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

33. What is the mechanism of action of Aspirin?
Delirium - Tremor - Nephrotoxicity
Bleeding.
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
No - it inhibits the release of Nor Epi

34. Name common Polymyxins
Inhibits Viral DNA polymerase
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Polymyxin B - Polymyxin E
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).

35. What is the clinical use for Sucralfate?
- Tetracycline
competitive inhibirot of aldosterone in the cortical collecting tubule
Peptic ulcer disease.
- Deferoxamine

36. What is Niclosamide used for?
GI disturbances.
Yes - it does not cross the placenta.
Inhibits reabsorption of uric acid.
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

37. What is the chemical name for Ganciclovir?
Inhibits DNA dependent RNA polymerase
DHPG (dihydroxy-2- propoxymethyl guanine)
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
reversible SLE- like syndrome

38. Name three calcium channel blockers?
No - it inhibits the release of Nor Epi
Nifedipine - Verapamil - Diltiazem
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

39. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Polymyxins
Hydralazine and Minoxidil

40. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Same as penicillin. Act as narrow spectrum antibiotics
- aminoglycosides - loop diuretics - cisplatin
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.

41. Adverse effects of Hydralazine?
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

42. What antimuscarinic agent is used in asthma and COPD?
Ipratropium
Inhibits Viral DNA polymerase
VACUUM your Bed Room'
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

43. List the specific antidote for this toxin: Arsenic (all heavy metals)
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
- Dimercaprol - succimer
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
For serious - Gram + multidrug - resistant organisms

44. Digoxin v. Digitoxin: protein binding?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Digitoxin 70% Digoxin 20-40%
- Fluoroquinolones
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities

45. Decrease Digoxin dose in renal failure?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
blocks SR Ca2+ channels
YES

46. 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
Tricyclic antidepressant.
- Antipsychotics
Dopamine; causes its release from intact nerve terminals

47. ACE inhibitors - toxicity?
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Treatment of infertility.
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

48. What is the MOA for Trimethoprim (TMP)?
Rheumatoid and osteoarthritis.
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Binds ergosterol - Disrupts fungal membranes
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

49. What side effect of using atropine to induce pupillary dilation would you expect?
- Penicillin
dizziness - flushing - constipation (verapamil) - nausea
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
- Dimercaprol - succimer

50. Which RT inhibitors cause a Rash?
loop diuretics - spironolactone
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Hypersensitivity reactions
Non - Nucleosides