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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. For Warfarin What is the Lab value to monitor
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
PT
Due to the presence of a bulkier R group
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

2. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Sotalol - Ibutilide - Bretylium - Amiodarone
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

3. What is the mechanism of action of Ticlopidine - Clopidogrel
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
It inhibits release of NE.
Gram + cocci - Gram - rods - and Anerobes
anuria - CHF

4. Name the common Aminoglycosides (5)
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
sedation - positive Coombs' test
Megaloblastic anemia - Leukopenia - Granulocytopenia

5. What populations are Floroquinolones contraindicated in? Why?
- Formaldehyde & formic acid - severe acidosis & retinal damage
Pregnant women - Children; because animal studies show Damage to Cartilage
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Amphetamine and Ephedrine

6. For Heparin What is the Onset of action
Activates antithrombin III
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
not a sulfonamide - but action is the same as furosemide
Rapid (seconds)

7. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
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
- Bleomycin - amiodarone - busulfan
No - hemicholinum block the uptake of Choline and thus Ach synthesis

8. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Interstitial nephritis
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
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

9. Explain differences between full and partial agonists(2).
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Act on same receptor - Full has greater efficacy
Beta antagonist.
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

10. Describe first - order kinetics?
Constant FRACTION eliminated per unit time.(exponential)
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
- NaHCO3

11. Ryanodine - site of action?
Sulfonamides - Trimethoprim
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
blocks SR Ca2+ channels

12. What is the mecanism of action of Sucralfate?
aPTT (intrinsic pathway)
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
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
Choline acetyltransferase

13. ________ ae not resistant to penicillinase - - but they are less susceptible than the other Beta lactams
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
- EDTA - dimercaprol - succimer - & penicillamine
Cephalosporins
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.

14. In What population does Gray Baby Syndrome occur? Why?
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
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.)
Premature infants - because they lack UDP- glucuronyl transferase
As an anticholinesterase it increases endogenous ACh and thus increases strength.

15. Which drug(s) cause this reaction: Cardiac toxicity?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Chronic Hepatitis A and B - Kaposi's Sarcoma
- Daunorubicin & Doxorubicin

16. What is the most common cause of Pt noncompliance with Macrolides?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
GI discomfort
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

17. Adenosine - clinical use?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
DOC in diagnosing and abolishing AV nodal arrhythmias
pulmonary edema - dehydration

18. What are four H2 Blockers?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Beta antagonist.
post MI and digitalis induced arrhythmias
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

19. What antimicrobial class is Aztreonam syngergestic with?
dry mouth - sedation - severe rebound hypertension
Decreases synthesis of Mycolic Acid
Aminoglycosides
Beta - lactam antibiotics

20. What is the MOA for the Macrolides?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

21. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
Treatment of infertility.
Inhibits CMV DNA polymerase
- Daunorubicin & Doxorubicin
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.

22. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
-100% oxygen - hyperbaric
Indirect agonist - uptake inhibitor
Rare.
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances

23. What is the MOA of Aztreonam?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
sedation - sleep alterations
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

24. Why does NE result in bradycardia?
proarrhythmic
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.
Hypersensitivity reactions
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

25. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Choline acetyltransferase

26. How is Amphotericin B administered for fungal meningitis?
Hypersensitivity reactions
proximal convoluted tubule - thin descending limb - and collecting duct
Intrathecally
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

27. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
- Bleomycin - amiodarone - busulfan
post MI and digitalis induced arrhythmias
- Tetracycline

28. What are four Sulfonylureas?
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Rifampin
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

29. List the specific antidote for this toxin: Antimuscarinic (anticholinergic)
Peptic ulcer disease.
No - warfarin - unlike heparin - can cross the placenta.
Pseudomonas species and Gram - rods
- Physostigmine salicylate

30. What is the major toxic side effect of Penicillin?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Hypersensitivity reactions

31. Quinidine - toxicity?
No
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

32. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Same as penicillin. Extended spectrum antibiotics
sedation - sleep alterations
Minor hepatotoxicity - Drug interactions (activates P450)

33. How is Griseofulvin used clinically?
GI distress - Skin rash - and Seizures at high plasma levels
Phosphorylation by a Viral Kinase
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Oral treatment of superficial infections

34. What is the memory key for the effect of aluminum hydroxide overuse?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
AluMINIMUM amount of feces.

35. Thiazides - site of action?
distal convoluted tubule (early)
- Shifts the curve down - reduces Vmax
Cilastatin
Neurotoxicity - Acute renal tubular necrosis

36. 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
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Amphotericin B - Nystatin - Fluconazole/azoles
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.

37. Which drug(s) cause this reaction: Hot flashes?
- Protamine
- Tamoxifen
hypertension - CHF - diabetic renal disease
aPTT (intrinsic pathway)

38. What are the clinical uses for Ticlopidine - Clopidogrel?
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Resistant Gram - infections
Because they require some residual islet function.
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

39. 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
Because they require some residual islet function.
Penicillin - V
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

40. What are two indirect acting adrenergic agonists?
amphetamine and ephedrine
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Cilastatin
- Act on same receptor - Full has greater efficacy

41. How does botulinum toxin result in respiratory arrest?
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Treatment of infertility.
Prevents the release of ACh - Which results in muscle paralysis.
Chronic gout.

42. List the specific antidote for this toxin: Warfarin
- Vitamin K & fresh frozen plasma
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
pulmonary edema - dehydration

43. Which cancer drugs inhibit nucleotide synthesis(3)?
Choline acetyltransferase
Cilastatin
- Methotrexate - 5 FU - 6 mercaptopurine
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

44. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

45. Antiarrhythmic class IB- clinical uses?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Pentavalent Antimony
post MI and digitalis induced arrhythmias

46. What are three toxicities of Leuprolied?
reversible SLE- like syndrome
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
1. Antiandrogen 2. Nausea 3. Vomiting
- Dimercaprol - succimer

47. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
scopolamine
Chronic anticoagulation.
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

48. What reversal agent could a Anes give to reverse the effects of Atropine
Antileukotriene; blocks leukotriene receptors.
Bethanechol - Neostigmine - physostigmine
Praziquantel
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.

49. List the mechanism - clinical use - & toxicity of Paclitaxel.
Mebendazole/Thiabendazole - Pyrantel Pamoate
- Corticosteroids - heparin
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- Atropine & pralidoxime

50. Which drug(s) cause this reaction: Oto and Nephrotoxicity (3)?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
- aminoglycosides - loop diuretics - cisplatin
Quinolones
Systemic mycoses