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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. List the specific antidote for this toxin: Heparin
Dopamine; causes its release from intact nerve terminals
Delirium - Tremor - Nephrotoxicity
- Protamine
- Tamoxifen

2. Esmolol - short or long acting?
very short acting
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Rash - Pseudomembranous colitis

3. What is the mechanism of Leuprolide?
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
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
Primaquine
Antibiotic - protein synthesis inhibitor.

4. What are four advantages of newer low - molecular - weight heparins (Enoxaparin)?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
- Deferoxamine
GI discomfort

5. What is the MOA of Griseofulvin?
Interferes with microtubule function - disrupts mitosis - inhibits growth
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
edrophonium (extremely short acting anticholinesterase)
Inhibits CMV DNA polymerase

6. What are two mechanisms of action of Propythiouracil?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.

7. Beta Blockers - CNS toxicity?
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
sedation - sleep alterations
Blocks Norepi - but not Dopamine

8. Explain potency in relation to full and partial agonists(2).
blocks SR Ca2+ channels
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Forms toxic metabolites in the bacterial cell - Bactericidal
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

9. What is the mechanism of action of Warfarin (Coumadin)?
competitive inhibirot of aldosterone in the cortical collecting tubule
Indirect agonist - uptake inhibitor
Disulfiram - like reaction with EtOH - Headache
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.

10. What is the mechanism of action of Clomiphene?
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
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.
- Penicillamine

11. Explain differences between full and partial agonists(2).
- Act on same receptor - Full has greater efficacy
Oral
Vd= (Amt. of drug in body/ Plasma drug conc.)
Pregnant women - Children; because animal studies show Damage to Cartilage

12. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Methylation of rRNA near Erythromycin's ribosome binding site
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.
post MI and digitalis induced arrhythmias

13. Aztreonam ________ to penicillinase
1. Weight gain 2. Hepatotoxicity (troglitazone)
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
Ipratropium
is resistant

14. What are two Glitazones?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
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.
1. Pioglitazone 2. Rosiglitazone.
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

15. Ca2+ channel blockers - clinical use?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
hypertension - angina - arrhythmias
Potent immunosuppressive used in organ transplant recipients.
fetal renal toxicity - hyperkalemia

16. What drug is used to diagnose myasthenia gravis?
edrophonium (extremely short acting anticholinesterase)
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Succinylcholine
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

17. Name three Antiarrhythmic drugs in class IV.
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Verapamil - Diltiazem - Bepridil
very short acting

18. Describe Phase II metabolism in liver(3)?
- Dimercaprol - succimer
- Shifts the curve to the right - increases Km
- Oxalic acid - Acidosis & nephrotoxicity
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

19. How does Ganciclovir's toxicity relate to that of Acyclovir?
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.
Ganciclovir is more toxic to host enzymes
competitive inhibirot of aldosterone in the cortical collecting tubule
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion

20. For Warfarin What is the Mechanism of action
Impairs the synthesis of vitamin K- dependent clotting factors
No - it inhibits the release of Nor Epi
cardiac muscle: Verapamil>Diltiazem>Nifedipine
bradycardia - AV block - CHF

21. Resistance mechanisms for Tetracycline
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.
Treatment of infertility.
Albuterol - tertbutaline
Decreased uptake or Increased transport out of cell

22. Digoxin v. Digitoxin: protein binding?
Small lipid - soluble molecule
Useful in muscle paralysis during surgery or mechanical ventilation.
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Digitoxin 70% Digoxin 20-40%

23. What is the category of drug names ending in - operidol (e.g. Haloperidol)
proximal convoluted tubule
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Butyrophenone (neuroleptic).
Digitoxin>95% Digoxin 75%

24. Name five Antiarrhythmic drugs in class II?
competitive inhibirot of aldosterone in the cortical collecting tubule
AmOxicillin has greater Oral bioavailability
propanolol - esmolol - metoprolol - atenolol - timolol
- Quinidine - quinine

25. What are four thrombolytics?
Bacitracin - Vancomycin
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
- Lithium
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

26. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Suramin
Norepinephrine (Alpha1 -2 and beta 1)
Erythromycin - Azithromycin - Clarithromycin

27. What is the category of drug names ending in - azepam (e.g. Diazepam)
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Large anionic polymer - acidic
Penicillin - G
Benzodiazepine.

28. Describe Phase I metabolism in liver(3)?
Beta - lactam antibiotics
Treatment of infertility.
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

29. What parasites are treated with Pyrantel Pamoate (more specific)?
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.
dry mouth - sedation - severe rebound hypertension
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)

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

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31. What microorganisms is Aztreonam not effective against?
Gram + and Anerobes
DOC in diagnosing and abolishing AV nodal arrhythmias
Antibiotic - protein synthesis inhibitor.
Tendonitis and Tendon rupture

32. Can Warfarin be used during pregnancy?
No - warfarin - unlike heparin - can cross the placenta.
- Chlorpromazine - thioridazine - haloperidol
- Ethanol - dialysis - & fomepizole
- Dimercaprol - succimer

33. Mannitol - clinical use?
Clavulanic acid
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Activates antithrombin III
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

34. What are three possible toxicities of NSAID usage?
CMV Retinitis in IC pts When Ganciclovir fails
1. Renal damage 2. Aplastic anemia 3. GI distress
- Clindamycin
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

35. For Warfarin What is the Route of administration
propanolol - esmolol - metoprolol - atenolol - timolol
- Corticosteroids - heparin
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Oral

36. List the mechanism - clinical use - & toxicity of 6 MP.
Binding to the presynaptic alpha 2 release modulating receptors
pulmonary edema - dehydration
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Ataxia - Dizziness - Slurred speech

37. Is resistant to penicillinase?
Imipenem
- Tetracycline
blocks SR Ca2+ channels
Tetracycline - Doxycycline - Demeclocycline - Minocycline

38. Reserpine will block the syntheis of this drug and but not its precursor.
post MI and digitalis induced arrhythmias
Blocks Norepi - but not Dopamine
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Ipratropium

39. Adverse effects of Methyldopa?

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40. Digoxin v. Digitoxin: half life?
Antileukotriene; blocks leukotriene receptors.
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Digitoxin 168hrs Digoxin 40 hrs

41. Describe first - order kinetics?
Gram + cocci - Gram - rods - and Anerobes
It affects beta receptors equally and is used in AV heart block (rare).
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Constant FRACTION eliminated per unit time.(exponential)

42. What are three toxicities of Propylthiouracil?
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
GI discomfort
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Yes

43. Digitalis - site of action?
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Inhalational general anesthetic.
Na/K ATPase
sedation - positive Coombs' test

44. What is the MOA of Ganciclovir?
- polymyxins
Short.
Butyrophenone (neuroleptic).
Inhibits CMV DNA polymerase

45. For Heparin What is the Lab value to monitor
aPTT (intrinsic pathway)
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

46. Which drug(s) cause this reaction: Thrombotic complications?
- Oral Contraceptives
viral kinase
Carbachol - pilocarpine - physostigmine - echothiophate
hypertension - CHF - diabetic renal disease

47. Which drug(s) cause this reaction: Cutaneous flushing (4)?
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Clavulanic acid
check PFTs - LFTs - and TFTs

48. Toxicities associated with Acyclovir?
Potent immunosuppressive used in organ transplant recipients.
Delirium - Tremor - Nephrotoxicity
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
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

49. What is an additional side effect of Methicillin?
fetal renal toxicity - hyperkalemia
Slow - limited by half lives of clotting factors
Interstitial nephritis
- N- acetylcystine

50. What is the mechanism of action of Omeprazole - Lansoprazole?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Inhibits CMV DNA polymerase
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.