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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 is the difference in receptor affinity of epinephrine at low doses? High doses?

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2. What are are the Sulfonylureas (general description) and What is their use?
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Antileukotriene; blocks leukotriene receptors.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

3. Adverse effects of Reserpine?
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Erythromycin - Azithromycin - Clarithromycin
Inhibit Ergosterol synthesis
sedation - depression - nasal stuffiness - diarrhea

4. Why is pyridostigmine effective in the treatment of myasthenia gravis?
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Potent immunosuppressive used in organ transplant recipients.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
As an anticholinesterase it increases endogenous ACh and thus increases strength.

5. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Cilastatin
Pseudomonas species and Gram - rods
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Cyclooxygenases (COX I - COX II).

6. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

7. Which diuretics increase urine Ca2+?
loop diuretics - spironolactone
amphetamine and ephedrine
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.
Digitoxin 70% Digoxin 20-40%

8. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
Rifampin (DOC) - minocycline
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Babiturate.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

9. Digoxin v. Digitoxin: excretion?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Digoxin=urinary Digitoxin=biliary
Aminoglycosides
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

10. What parasitic condition is treated with Ivermectin?

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11. Ibutilide - toxicity?
DOC in diagnosing and abolishing AV nodal arrhythmias
torsade de pointes
reversible SLE- like syndrome
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone

12. What is the memory key to remember Which pathway (extrinsic vs. intrinsic) and Which lab value Warfarin affects?
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
1. Weight gain 2. Hepatotoxicity (troglitazone)
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Amphotericin B - Nystatin - Fluconazole/azoles

13. Acetazolamide causes?

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14. Antiarrhythmic class IV- primary 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.
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
AV nodal cells
Tricyclic antidepressant.

15. Name the common Nucleoside Reverse Transcriptase Inhibitors
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Epinephirine(Alpha1 -2 and Beta 1 -2)
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

16. Digitalis - site of action?
Na/K ATPase
Polymyxins
physostigmine
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome

17. Adverse effects of Clonidine?
dry mouth - sedation - severe rebound hypertension
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Slow - limited by half lives of clotting factors
- Daunorubicin & Doxorubicin

18. What is combination TMP- SMZ used to treat?
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Clavulanic acid

19. Toxicities associated with Acyclovir?
Delirium - Tremor - Nephrotoxicity
dry mouth - sedation - severe rebound hypertension
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

20. For Warfarin What is the Duration of action
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Prophylaxis for Influenza A - Rubella; Parkinson's disease
- Chlorpromazine - thioridazine - haloperidol
Chronic (weeks or months)

21. Bretyllium - toxicity?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Modification via Acetylation - Adenylation - or Phosphorylation
new arrhythmias - hypotension

22. Furosemide - toxicity? (OH DANG)
- Flumazenil
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Gram + cocci - Gram - rods - and Anerobes
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

23. Ethacrynic Acid - clinical use?
Diuresis in pateints with sulfa allergy
new arrhythmias - hypotension
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide

24. What is the clinical utility of cocaine?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
The only local anesthetic with vasoconstrictive properties.
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

25. What is the category of drug names ending in - azol (e.g. Ketoconazole)
No - warfarin - unlike heparin - can cross the placenta.
Antifungal.
Small lipid - soluble molecule
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

26. Which drug(s) cause this reaction: Oto and Nephrotoxicity (3)?
Forms toxic metabolites in the bacterial cell - Bactericidal
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
INH: Injures Neurons and Hepatocytes
- aminoglycosides - loop diuretics - cisplatin

27. Are Ampicillin and Amoxicillin are not...
penicillinase resistant
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Beta - lactam antibiotics

28. Where does Griseofulvin deposit?
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Norepinephrine (Alpha1 -2 and beta 1)
Keratin containing tissues - e.g. - nails
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

29. Adverse effect of Nitroprusside?
Antifungal.
Premature infants - because they lack UDP- glucuronyl transferase
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
cyanide toxicity (releases CN)

30. What is the mechanism of action of Omeprazole - Lansoprazole?
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Digitoxin>95% Digoxin 75%
- Vinca alkaloids(inhibit MT) - Paclitaxel
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

31. What is a prerequisite for Acyclovir activation?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
It must be Phosphorylated by Viral Thymidine Kinase
decrease

32. List some specifics of lead poisoning(4)?
- Haloperidol - chlorpromazine - reserpine - MPTP
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Benzodiazepine.
- Cloazapine - carbamazapine - colchicine - PTU

33. What conditions would you use dantrolene?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Competitive inibitor of progestins at progesterone receptors.

34. Which cancer drugs effect nuclear DNA (4)?
- N- acetylcystine
Vd= (Amt. of drug in body/ Plasma drug conc.)
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Inhibit viral DNA polymerase

35. How do we stop angina?
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Potent immunosuppressive used in organ transplant recipients.
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide

36. Which drug(s) cause this reaction: Gynecomastia (6)?
Those patients who are taking nitrates.
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)

37. What is the mechanism of action of the Sulfonylureas?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

38. Which drug(s) cause this reaction: Photosensitivity(3)?
H2 antagonist
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
- Tetracycline - amiodarone - sulfonamides
Decreased uptake or Increased transport out of cell

39. Cocaine casues vasoconstriction and local anesthesia by What mechanism
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Indirect agonist - uptake inhibitor

40. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Digitoxin 70% Digoxin 20-40%
Amphetamine and Ephedrine
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Tricyclic antidepressant.

41. What is the category of drug names ending in - ane (e.g. Halothane)
Inhalational general anesthetic.
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Inhibit Ergosterol synthesis
1. Antiandrogen 2. Nausea 3. Vomiting

42. What are the Macrolides used for clinically?
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Acute (hours)
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Liver

43. Acetazolamide - site of action?
proximal convoluted tubule
Ibuprofen - Naproxen - and Indomethacin
Give an antichloinesterase - neostigmine - edrophonium - etc
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

44. Which individuals are predisposed to Sulfonamide - induced hemolysis?
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
G6PD deficient individuals

45. What is the MOA of Polymyxins?
Bleeding.
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Competitive inibitor of progestins at progesterone receptors.

46. Verapamil has similar action to?
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
No - warfarin - unlike heparin - can cross the placenta.
Beta Blockers
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

47. What is the category of drug names ending in - pril (e.g. Captopril)
ACE inhibitor.
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Give an antichloinesterase - neostigmine - edrophonium - etc

48. Why is reserpine effective in treating HTN?
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
hyperaldosteronism - K+ depletion - CHF
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Binding to the presynaptic alpha 2 release modulating receptors

49. What is the mechanism of action of Acetaminophen?
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Anaerobes
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
- Vitamin K & fresh frozen plasma

50. Name three Antiarrhythmic drugs in class IB.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Lidocaine - Mexiletine - Tocainide
Slow - limited by half lives of clotting factors
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor