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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. Why does NE result in bradycardia?
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.
GI distress - Skin rash - and Seizures at high plasma levels
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Because they require some residual islet function.

2. Furosemide - class and mechanism?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
- Tetracycline - amiodarone - sulfonamides

3. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
- Fluoroquinolones
- Cloazapine - carbamazapine - colchicine - PTU
Binding to the presynaptic alpha 2 release modulating receptors
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

4. What is the MOA of the RT Inhibitors?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
CMV Retinitis in IC pts When Ganciclovir fails

5. Which drug(s) cause this reaction: Gingival hyperplasia?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
- Phenytoin
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.

6. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
local anesthetic. CNS stimulation or depression. CV depression.
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Norepinephrine (Alpha1 -2 and beta 1)
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)

7. Ryanodine - site of action?
blocks SR Ca2+ channels
Delirium - Tremor - Nephrotoxicity
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

8. Ethacrynic Acid - mechanism?
not a sulfonamide - but action is the same as furosemide
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Interstitial nephritis

9. Which drug(s) cause this reaction: Cutaneous flushing (4)?
Doxycycline - because it is fecally eliminated
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH

10. Name the common Fluoroquinolones (6)
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Give an antichloinesterase - neostigmine - edrophonium - etc
sedation - depression - nasal stuffiness - diarrhea
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

11. What effect would atropine have on a patient with peptic ulcer disease?
Cephalosporins
Neutropenia
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

12. List the specific antidote for this toxin: Copper
- Penicillamine
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
distal convoluted tubule (early)
Activates antithrombin III

13. Does Warfarin have a long - medium - or short half life?
toxic
Long.
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
It must be Phosphorylated by Viral Thymidine Kinase

14. List the specific antidote for this toxin: Acetaminophen
- N- acetylcystine
Digoxin=urinary Digitoxin=biliary
Carbachol - pilocarpine - physostigmine - echothiophate
CL= (rate of elimination of drug/ Plasma drug conc.)

15. What cholinomimetics might your pt be taking for his glaucoma
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Inhibits Viral DNA polymerase
Carbachol - pilocarpine - physostigmine - echothiophate

16. What process does Zafirlukast interfere with?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Quinolones
Leukotrienes increasing bronchial tone.

17. Which drug(s) cause this reaction: Cough?
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
- ACE inhibitors (Losartan>no cough)
Blocks Norepi - but not Dopamine
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

18. Common toxicities associated with Griseofulvin?
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Teratogenic - Carcinogenic - Confusion - Headaches
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

19. How do you treat coma in the ER (4)?
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Gram + - Gram - - Norcardia - Chlamydia
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.

20. List the specific antidote for this toxin: Carbon monoxide
Pralidoxime regenerates active cholinesterase.
Blood
-100% oxygen - hyperbaric
- Ethosuxamide - sulfonamides - lamotrigine

21. What are four advantages of newer low - molecular - weight heparins (Enoxaparin)?
Disulfiram - like reaction with EtOH - Headache
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Antifungal.
carbonic anhydrase inhibitors - K+ sparing diuretics

22. Adverse effects of Loop Diuretics?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
proarrhythmic
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

23. What are toxic side effects for Metronidazole?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Phenothiazine (neuroleptic - antiemetic).
Acute (hours)
Disulfiram - like reaction with EtOH - Headache

24. Digoxin v. Digitoxin: bioavailability?
- Vitamin K & fresh frozen plasma
Carbachol - pilocarpine - physostigmine - echothiophate
Digitoxin>95% Digoxin 75%
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

25. What anticholinesterase crosses the blood - brain - barrier?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
physostigmine
Binding to the presynaptic alpha 2 release modulating receptors
hyperaldosteronism - K+ depletion - CHF

26. How does a noncompetitive antagonist effect an agonist?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
- Shifts the curve down - reduces Vmax
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Inhibit Ergosterol synthesis

27. Describe first - order kinetics?
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Interferes with microtubule function - disrupts mitosis - inhibits growth
Constant FRACTION eliminated per unit time.(exponential)

28. What are the clinical uses for Imipenem/cilastatin?
Gram + cocci - Gram - rods - and Anerobes
Paranteral (IV - SC)
Cephalosporins
- Methylene blue

29. What is a sign of toxicity with the use of thrombolytics?
Bleeding.
blocks SR Ca2+ channels
amphetamine and ephedrine
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

30. Mannitol - contraindications?
anuria - CHF
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Large anionic polymer - acidic
TMP- SMZ (DOC) - aerosolized pentamidine

31. What antimicrobial class is Aztreonam syngergestic with?
Pentavalent Antimony
Aminoglycosides
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate

32. Which drug(s) cause this reaction: Cinchonism (2)?
- Quinidine - quinine
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Protamine sulfate
Norepinephrine

33. List the specific antidote for this toxin: Warfarin
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
- Vitamin K & fresh frozen plasma
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Gemfibrozil - Clofibrate

34. What type of neurological blockade would hexamethonium create?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
- B51Naloxone / naltrexone (Narcan)
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

35. What are common toxicities related to Vancomycin therapy?

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36. What is the only depolarizing neuromuscular blocking agent?
Early myocardial infarction.
- Vitamin K & fresh frozen plasma
Succinylcholine
Mg = Must go to the bathroom.

37. Which diuretics increase urine Ca2+?
cyanide toxicity (releases CN)
Scopolamine
loop diuretics - spironolactone
No

38. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Constant FRACTION eliminated per unit time.(exponential)
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Foscarnet = pyroFosphate analog

39. List the specific antidote for this toxin: Tricyclic antidepressants
- Penicillamine
- NaHCO3
Interstitial nephritis
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

40. What are two conditions in Which COX-2 inhibitors might be used?
Rheumatoid and osteoarthritis.
Chronic anticoagulation.
Yes
Tricyclic antidepressant.

41. List the specific antidote for this toxin: Iron
- Deferoxamine
ACE inhibitor.
Nevirapine - Delavirdine
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

42. Adverse effects of Hydrochlorothiazide?
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Nephrotoxicity
Yes
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

43. What are three possible complications of Heparin therapy?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Pseudomembranous colitis (C. difficile) - fever - diarrhea
- Dimercaprol - succimer
for RSV

44. What are Amantadine - associated side effects?
- Ethosuxamide - sulfonamides - lamotrigine
Ataxia - Dizziness - Slurred speech
1. Antiandrogen 2. Nausea 3. Vomiting
penicillinase resistant

45. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
sedation - depression - nasal stuffiness - diarrhea
sedation - positive Coombs' test
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
- Normalize K+ - Lidocaine - & Anti - dig Mab

46. What are two toxicities associated with Cyclosporine?
- Deferoxamine
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Beta1 more than B2

47. For Warfarin What is the Ability to inhibit coagulation in vitro
No
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Potent immunosuppressive used in organ transplant recipients.
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

48. What is Metronidazole used for clinically?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Does not cross
Erectile dysfunction.
Carbachol - pilocarpine - physostigmine - echothiophate

49. ___________ are Teratogenic
Blocks Influenza A and RubellA; causes problems with the cerebellA
Methylxanthine.
Aminoglycosides
- Flumazenil

50. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
Sildenafil fills the penis
- Ethosuxamide - sulfonamides - lamotrigine
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
cardiac depression - peripheral edema - flushing - dizziness - constipation