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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. Antiarrhythmic class II- effects?
Mg = Must go to the bathroom.
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Binding to the presynaptic alpha 2 release modulating receptors

2. What are three unwanted effects of Mifepristone?
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Cell membrane Ca2+ channels of cardiac sarcomere

3. What is the possible mechanism and effect of Metformin in treating diabetes?
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
post MI and digitalis induced arrhythmias
- Dimercaprol - succimer
Cyclooxygenases (COX I - COX II).

4. What is the main clinical use for the thrombolytics?
Norepinephrine (Alpha1 -2 and beta 1)
Early myocardial infarction.
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

5. Which drug(s) cause this reaction: G6PD hemolysis(8)?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Megaloblastic anemia - Leukopenia - Granulocytopenia
- Chlorpromazine - thioridazine - haloperidol
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol

6. What is the category of drug names ending in - navir (e.g. Saquinavir)
collecting ducts
Beta - lactam antibiotics
Protease inhibitor.
Phenothiazine (neuroleptic - antiemetic).

7. What is used to reverse the action of Heparin?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

8. How does NE modulate its own release? What other neurotransmitter has this same effect?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

9. Hydralazine - class and mechanism?
decrease conduction velocity - increase ERP - increase PR interval
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.
blocks SR Ca2+ channels
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

10. What is the MOA for Metronidazole?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Because they require some residual islet function.
- Ammonium Chloride
Forms toxic metabolites in the bacterial cell - Bactericidal

11. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
- Disulfram & also sulfonylureas - metronidazole
Binding to the presynaptic alpha 2 release modulating receptors

12. How does Ganciclovir's toxicity relate to that of Acyclovir?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Tricyclic antidepressant.
Ganciclovir is more toxic to host enzymes
Resistant Gram - infections

13. Furosemide increases the excretion of What ion?
Ca2+ (Loops Lose calcium)
Beta Blockers
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Systemic mycoses

14. List the specific antidote for this toxin: Carbon monoxide
NO
Dopamine
-100% oxygen - hyperbaric
Binds to the Pyrophosphate Binding Site of the enzyme

15. How would you reverse the effect of a neuromuscular blocking agent?
reversible SLE- like syndrome
Give an antichloinesterase - neostigmine - edrophonium - etc
Botulinum
GI side effects. (Indomethacin is less toxic - more commonly used.)

16. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
1. Weight gain 2. Hepatotoxicity (troglitazone)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

17. List the mechanism - clinical use - & toxicity of Tamoxifen.
Cilastatin
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Methylation of rRNA near Erythromycin's ribosome binding site
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

18. Does Heparin have a long - medium - or short half life?
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Short.
Prevents the release of ACh - Which results in muscle paralysis.
Erythromycin - Azithromycin - Clarithromycin

19. Which drug(s) cause this reaction: Disulfram - like reaction (4) ?
physostigmine
Rifampin (DOC) - minocycline
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Ipratropium

20. List the mechanism - clinical use - & toxicity of Methotrexate.
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Carbenicillin - Piperacillin - and Ticarcillin
Blocks Norepi - but not Dopamine
depresses ectopic pacemakers - especially in digoxin toxicity

21. What is the category of drug names ending in - zosin (e.g. Prazosin)
Alpha -1 antagonist
cortical collecting tubule
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
HTN - CHF - calcium stone formation - nephrogenic DI.

22. Describe Phase II metabolism in liver(3)?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Albuterol - tertbutaline
Botulinum
dry mouth - sedation - severe rebound hypertension

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

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24. Digoxin v. Digitoxin: half life?
Nucleosides
Decreases synthesis of Mycolic Acid
Digitoxin 168hrs Digoxin 40 hrs
- Disulfram & also sulfonylureas - metronidazole

25. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
Digitoxin 70% Digoxin 20-40%
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

26. What is treated with Chloroquine - Quinine - Mefloquine?
Malaria (P. falciparum)
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
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.
cardiac muscle: Verapamil>Diltiazem>Nifedipine

27. What is the mechanism of action of Omeprazole - Lansoprazole?
Slow - limited by half lives of clotting factors
Pseudomonas species and Gram - rods
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.
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

28. What is a common drug interaction associated with Griseofulvin?
Increases coumadin metabolism
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Ipratropium

29. What drug is given for Pneumocystis carinii prophylaxis?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Rash - Pseudomembranous colitis
Pentamidine
Blocks Norepi - but not Dopamine

30. What are Polymyxins used for?
Cell membrane Ca2+ channels of cardiac sarcomere
AluMINIMUM amount of feces.
Resistant Gram - infections
- Vinca alkaloids(inhibit MT) - Paclitaxel

31. Preferential action of the Ca2+ channel blockers at cardiac muscle?
depresses ectopic pacemakers - especially in digoxin toxicity
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Dopamine; causes its release from intact nerve terminals
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time

32. What do you treat Nematode/roundworm (pinworm - whipworm) infections with?
Aminoglycosides
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Same as penicillin. Extended spectrum antibiotics
Mebendazole/Thiabendazole - Pyrantel Pamoate

33. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
GET on the Metro
- Normalize K+ - Lidocaine - & Anti - dig Mab
Chronic anticoagulation.
Epinephirine(Alpha1 -2 and Beta 1 -2)

34. Are not penicillinase resistant
- EDTA - dimercaprol - succimer - & penicillamine
- Dimercaprol - succimer
Carbenicillin - Piperacillin - and Ticarcillin
Leukotrienes increasing bronchial tone.

35. Hydralazine - toxicity?
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
compensatory tachycardia - fluid retention - lupus - like syndrome
Antifungal.
- Quinidine - quinine

36. What are four advantages of newer low - molecular - weight heparins (Enoxaparin)?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Dopamine; causes its release from intact nerve terminals

37. List the mechanism - clinical use - & toxicity of Etoposide.
Inhibits CMV DNA polymerase
- B51Naloxone / naltrexone (Narcan)
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.

38. What are two conditions in Which COX-2 inhibitors might be used?
Succinylcholine
dry mouth - sedation - severe rebound hypertension
Rheumatoid and osteoarthritis.
anuria - CHF

39. List the mechanism - clinical use - & toxicity of 5 FU.
Severe Gram - rod infections.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions

40. What is the category of drug names ending in - cillin (e.g. Methicillin)
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
It affects beta receptors equally and is used in AV heart block (rare).
carbonic anhydrase inhibitors - K+ sparing diuretics
Penicillin.

41. What organisms does Griseofulvin target?
post MI and digitalis induced arrhythmias
Lidocaine - Mexiletine - Tocainide
- Physostigmine salicylate
Dermatophytes (tinea - ringworm)

42. Which drug(s) cause this reaction: Gynecomastia (6)?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Paranteral (IV - SC)

43. What are two clinical uses of Azathioprine?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
- Atropine & pralidoxime

44. Name some common Sulfonamides (4)
Yes - it does not cross the placenta.
Methicillin - Nafcillin - and Dicloxacillin
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

45. MOA: Disrupt bacterial/fungal cell membranes
Tendonitis and Tendon rupture
Polymyxins
Hypersensitivity reactions
cardiac depression - peripheral edema - flushing - dizziness - constipation

46. What is the mechanism of action of Clomiphene?
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
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.
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
1. Renal damage 2. Aplastic anemia 3. GI distress

47. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
Tricyclic antidepressant.
Methylation of rRNA near Erythromycin's ribosome binding site
is resistant
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

48. What is the MOA of Griseofulvin?
Interferes with microtubule function - disrupts mitosis - inhibits growth
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
hypertension - CHF - diabetic renal disease

49. List the specific antidote for this toxin: Iron
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Erythromycin - Azithromycin - Clarithromycin
- Normalize K+ - Lidocaine - & Anti - dig Mab
- Deferoxamine

50. Adverse effects of Captopril?
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Mg = Must go to the bathroom.
IV vitamin K and fresh frozen plasma