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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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1. What are the phases of succinylcholine neuromuscular blockade?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Epinephirine(Alpha1 -2 and Beta 1 -2)
GI disturbances.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

2. Ca2+ sensitizers'- site of action?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
troponin - tropomyosin system
loop diuretics - thiazides

3. Mannitol - mechanism?
The PTT.
Oral treatment of superficial infections
Digitoxin 168hrs Digoxin 40 hrs
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

4. What are three clinical uses of the NSAIDs?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Treatment of infertility.
Carbachol - pilocarpine - physostigmine - echothiophate

5. What is a sign of toxicity with the use of thrombolytics?
Inhibt Assembly of new virus by Blocking Protease Enzyme
Bleeding.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

6. What are Polymyxins used for?
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Protamine sulfate
Resistant Gram - infections

7. What microorganisms are Aminoglycosides ineffective against?
Anaerobes
anticholinesterase glaucoma
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

8. How do you treat coma in the ER (4)?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Neurotoxicity - Acute renal tubular necrosis
Gram + cocci - Gram - rods - and Anerobes
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

9. List the specific antidote for this toxin: Salicylates
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
- Alkalinize urine & dialysis

10. Name three Antiarrhythmic drugs in class IB.
depresses ectopic pacemakers - especially in digoxin toxicity
Pralidoxime regenerates active cholinesterase.
Lidocaine - Mexiletine - Tocainide
The PTT.

11. Toxic effects of TMP include?
depresses ectopic pacemakers - especially in digoxin toxicity
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Malaria (P. falciparum)
Megaloblastic anemia - Leukopenia - Granulocytopenia

12. Beta Blockers - BP?
decrease
Methylxanthine.
RESPIre
Severe Gram - rod infections.

13. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Useful in muscle paralysis during surgery or mechanical ventilation.
Diuresis in pateints with sulfa allergy
Reversible block of histamine H2 receptors

14. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
- ED 50 is less than the Km (less than 50% of receptors)
GI disturbances.
Staphlococcus aureus
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

15. List the specific antidote for this toxin: Anticholinesterases (organophosphate.)
Antileukotriene; blocks synthesis by lipoxygenase.
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
- Corticosteroids - heparin
- Atropine & pralidoxime

16. What are the clinical uses for Imipenem/cilastatin?
Quinolones
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Nifedipine - Verapamil - Diltiazem
Gram + cocci - Gram - rods - and Anerobes

17. What is the memory key for organisms treated with Tetracyclines?

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18. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
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.
No - hemicholinum block the uptake of Choline and thus Ach synthesis
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

19. A group of pts are rushed into the ER complaining of excessive sweating - tearing - salivation - HA - N and V - muscle twitching - difficulty breathing and diarrhea. What drug would be the most effective immediate tx
TMP- SMZ (DOC) - aerosolized pentamidine
- Tricyclic antidepressants
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
VACUUM your Bed Room'

20. List the mechanism - clinical use - & toxicity of Cyclophosphamide.
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
physostigmine
Useful in muscle paralysis during surgery or mechanical ventilation.

21. What is Fluconazole specifically used for?
1. Renal damage 2. Aplastic anemia 3. GI distress
GET on the Metro
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Chronic gout.

22. Which cancer drugs work at the level of proteins(2)?
Does not cross
- Glucocorticoid withdrawal
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
- Vinca alkaloids(inhibit MT) - Paclitaxel

23. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Beta antagonist.
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism

24. What are major side effects of Methicillin - Nafcillin - and Dicloxacillin?
proximal convoluted tubule - thin descending limb - and collecting duct
Sildenafil fills the penis
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Hypersensitivity reactions

25. List the specific antidote for this toxin: Beta Blockers
Minor hepatotoxicity - Drug interactions (activates P450)
AZT
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
- Glucagon

26. How is Vancomycin used clinically?
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
For serious - Gram + multidrug - resistant organisms
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
edrophonium (extremely short acting anticholinesterase)

27. What is the formula for Volume of distribution (Vd)
Yes
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Vd= (Amt. of drug in body/ Plasma drug conc.)
ACE inhibitor.

28. List the specific antidote for this toxin: Carbon monoxide
-100% oxygen - hyperbaric
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
first dose orthostatic hypotension - dizziness - headache

29. What is the effect of epinephrine infusion on bp and pulse pressure?
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Only in limited amounts
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Rifampin

30. Name four HMG- CoA reductase inhibitors.
- Alkalate DNA - Brain tumors - CNS toxicity
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
It must be Phosphorylated by Viral Thymidine Kinase
No - warfarin - unlike heparin - can cross the placenta.

31. What type of gout is treated with Probenacid?
Chronic gout.
penicillinase resistant
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods

32. Describe Phase I metabolism in liver(3)?
depresses ectopic pacemakers - especially in digoxin toxicity
Antileukotriene; blocks synthesis by lipoxygenase.
cyanide toxicity (releases CN)
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450

33. List the specific antidote for this toxin: Benzodiazepines
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Ceftriaxone
- Flumazenil
Succinylcholine

34. What are Fluoroquinolones indicated for? (3)
Inhalational general anesthetic.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Ipratropium
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

35. Ca2+ channel blockers - clinical use?
CL= (rate of elimination of drug/ Plasma drug conc.)
- Ethanol - dialysis - & fomepizole
reversible SLE- like syndrome
hypertension - angina - arrhythmias

36. Why would dopamine be useful in treating shock?
hypertension - angina - arrhythmias
1. Antiandrogen 2. Nausea 3. Vomiting
Decreased uptake or Increased transport out of cell
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

37. What is Metronidazole used for clinically?
hyperaldosteronism - K+ depletion - CHF
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
CMV Retinitis in IC pts When Ganciclovir fails
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

38. How is Amphotericin B used clinically?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Polymyxin B - Polymyxin E
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

39. What is the major toxic side effect of Penicillin?
Hypersensitivity reactions
effective in torsade de pointes and digoxin toxicity
- EDTA - dimercaprol - succimer - & penicillamine
Primaquine

40. Name two LPL stimulators.
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)
Gemfibrozil - Clofibrate
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Penicillin - V

41. Sotalol - toxicity?
With supplemental Folic Acid
torsade de pointes - excessive Beta block
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
It inhibits release of NE.

42. What is the mechanism of action of Warfarin (Coumadin)?
Staphlococcus aureus
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility

43. Isopoterenol was given to a patient with a developing AV block - why?
Norepinephrine
DOC in diagnosing and abolishing AV nodal arrhythmias
Stimulates beta adrenergic receptors
Early myocardial infarction.

44. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Same as penicillin. Extended spectrum antibiotics
Potent immunosuppressive used in organ transplant recipients.
Pseudomembranous colitis (C. difficile) - fever - diarrhea

45. What is the category of drug names ending in - operidol (e.g. Haloperidol)
Butyrophenone (neuroleptic).
- Quinidine - quinine
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Potent immunosuppressive used in organ transplant recipients.

46. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
NO
Pseudomonas species and Gram - rods

47. 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.
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Keratin containing tissues - e.g. - nails

48. Adverse effect of Nitroprusside?
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
- Phenytoin
cyanide toxicity (releases CN)
Modification via Acetylation

49. List the specific antidote for this toxin: Arsenic (all heavy metals)
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
- Dimercaprol - succimer
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

50. What is the clinical use for Warfarin?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Chronic anticoagulation.
- polymyxins