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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. What are the major toxic side effects of the Cephalosporins?
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
cortical collecting tubule
physostigmine
- Glucocorticoid withdrawal

2. What are the four conditions in Which Omeprazole - Lansoprazole is used?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

3. What is the MOA for Metronidazole?
Captopril - Enalapril - Lisinopril
Leukotrienes increasing bronchial tone.
Forms toxic metabolites in the bacterial cell - Bactericidal
Gemfibrozil - Clofibrate

4. Isopoterenol was given to a patient with a developing AV block - why?
Stimulates beta adrenergic receptors
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Amphotericin B - Nystatin - Fluconazole/azoles
cyanide toxicity (releases CN)

5. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Nifedipine - Verapamil - Diltiazem
Beta - lactam antibiotics
Binding to the presynaptic alpha 2 release modulating receptors
As an anticholinesterase it increases endogenous ACh and thus increases strength.

6. Antiarrhythmic class II- toxicity?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Pentavalent Antimony
Methylxanthine.
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia

7. List the mechanism - clinical use - & toxicity of Nitrosureas.
Small lipid - soluble molecule
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
- Alkalate DNA - Brain tumors - CNS toxicity
Digitoxin 168hrs Digoxin 40 hrs

8. What type of patient should not take Misoprostol and why?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Methylation of rRNA near Erythromycin's ribosome binding site
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
No - it inhibits the release of Nor Epi

9. What is the mechanism of action of Clomiphene?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
cross - allergenic
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.
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents

10. Reserpine will block the syntheis of this drug and but not its precursor.
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Only in limited amounts
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Blocks Norepi - but not Dopamine

11. What is the mechanism of action of Ticlopidine - Clopidogrel
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
decrease conduction velocity - increase ERP - increase PR interval
Clavulanic acid
Disulfiram - like reaction with EtOH - Headache

12. Which drug(s) cause this reaction: Thrombotic complications?
- Oral Contraceptives
collecting ducts
Rifampin
new arrhythmias - hypotension

13. What parasites are treated with Pyrantel Pamoate (more specific)?
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Ipratropium
Methicillin - Nafcillin - and Dicloxacillin
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

14. What are common toxicities associated with Macrolides? (4)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Tricyclic antidepressant.
Interferes with microtubule function - disrupts mitosis - inhibits growth
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

15. What are two Alpha - glucosidase inhibitors?
Na/K ATPase
The PT.
1. Acarbose 2. Miglitol
not a sulfonamide - but action is the same as furosemide

16. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Primaquine
Hypersensitivity reactions

17. The COX-2 inhibitors (celecoxib - rofecoxib) have similar side effects to the NSAIDs with What one exception?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Aminoglycosides
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.
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

18. How does a competitive antagonist effect an agonist?
- Oral Contraceptives
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
- Shifts the curve to the right - increases Km

19. Name some common Tetracyclines (4)
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Disulfiram - like reaction with EtOH - Headache
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
- Methylene blue

20. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
TMP- SMZ
Acetylcholinesterase; ACh is broken down into choline and acetate.
Epinephirine(Alpha1 -2 and Beta 1 -2)
Hypersensitivity reactions

21. What are common side effects of Protease Inhibitors?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
viral kinase
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)

22. Does Heparin have a long - medium - or short half life?
Na/K ATPase
- Clindamycin
Short.
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.

23. While at a tail gait party - you bite into a sandwich that a yellow jacket is also enjoying. Knowing your allergy to this creature - What should you do?
Digitoxin 70% Digoxin 20-40%
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Fast vs. Slow Acetylators
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.

24. Antiarrhythmic class IV- toxicity?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Resistant Gram - infections
AmOxicillin has greater Oral bioavailability

25. Ryanodine - site of action?
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.
severe hypertension - CHF
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
blocks SR Ca2+ channels

26. Antiarrhythmic class II- effects?
Fast vs. Slow Acetylators
- Isoniazid
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Vd= (Amt. of drug in body/ Plasma drug conc.)

27. List the specific antidote for this toxin: Heparin
- Protamine
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Gram + - Gram - - Norcardia - Chlamydia
block Na+ channels in the cortical collecting tubule

28. Which drug(s) cause this reaction: Gray baby syndrome?
Quinidine - Amiodarone - Procainamide - Disopyramide
hyperaldosteronism - K+ depletion - CHF
- Chloramphenicol
Methylxanthine.

29. For Heparin What is the Mechanism of action
Sildenafil fills the penis
- Atropine & pralidoxime
Activates antithrombin III
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

30. Describe Phase II metabolism in liver(3)?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Fast vs. Slow Acetylators

31. Adverse effects of Losartan?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
No - warfarin - unlike heparin - can cross the placenta.
fetal renal toxicity - hyperkalemia
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

32. Antimicrobial prophylaxis for Syphilis
Teratogenic - Carcinogenic - Confusion - Headaches
Benzathine penicillin G
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
No - warfarin - unlike heparin - can cross the placenta.

33. What is the mechanism of action of the glucocorticoids?
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.
Protease Inhibitors and Reverse Transcriptase Inhibitors
The PT.
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

34. These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
Amphetamine and Ephedrine
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Polymyxins
- Shifts the curve down - reduces Vmax

35. Name three K+ sparing diuretics?
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Choline acetyltransferase

36. What are four H2 Blockers?
- Nitrate - hydroxocobalamin thiosulfate
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

37. What drug is used during the pregnancy of an HIV+ mother? - Why?
AZT - to reduce risk of Fetal Transmission
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Chronic Hepatitis A and B - Kaposi's Sarcoma
No - warfarin - unlike heparin - can cross the placenta.

38. What is the mechanism of Leuprolide?
Nitrates
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
Lidocaine - Mexiletine - Tocainide
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

39. What is the main clinical use for the thrombolytics?
Ca2+ (Loops Lose calcium)
Early myocardial infarction.
Competitive inibitor of progestins at progesterone receptors.
Dopamine

40. How does angiotensin II affect NE release?
Dopamine
AZT - to reduce risk of Fetal Transmission
Botulinum
It acts presynaptically to increase NE release.

41. What are Amantadine - associated side effects?
distal convoluted tubule (early)
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Ataxia - Dizziness - Slurred speech
cyanide toxicity (releases CN)

42. Digoxin v. Digitoxin: half life?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
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.
Digitoxin 168hrs Digoxin 40 hrs
fetal renal toxicity - hyperkalemia

43. For Heparin What is the Treatment for overdose
thick ascending limb
Nevirapine - Delavirdine
penicillinase resistant
Protamine sulfate

44. Which drug(s) cause this reaction: Tendonitis and rupture?
Phenothiazine (neuroleptic - antiemetic).
- Fluoroquinolones
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
troponin - tropomyosin system

45. How is Ribavirin used clinically?
for RSV
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Benzodiazepine.

46. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Nitrates
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Pseudomonas species and Gram - rods
G6PD deficient individuals

47. Why does NE result in bradycardia?
For serious - Gram + multidrug - resistant organisms
sedation - sleep alterations
Interstitial nephritis
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

48. MOA: Block peptidoglycan synthesis
Bacitracin - Vancomycin
Digoxin=urinary Digitoxin=biliary
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
Methylxanthine.

49. K+ sparing diuretics - clinical use?
hyperaldosteronism - K+ depletion - CHF
Does not cross
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
cholestyramine - colestipol

50. What is the mechanism of action of Aspirin?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Aminoglycosides - Tetracyclines
Pituitary hormone.
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.