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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 are the clinical indications for bethanechol?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
- Cloazapine - carbamazapine - colchicine - PTU
Useful in muscle paralysis during surgery or mechanical ventilation.
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome

2. While at a tail gait party - you bite into a sandwich that a yellow jacket is also enjoying. Knowing your allergy to this creature - What should you do?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
hypertension - CHF - diabetic renal disease
AZT
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

3. Name the Protease Inhibitors (4)
Blocks Norepi - but not Dopamine
- Vinca alkaloids(inhibit MT) - Paclitaxel
Saquinavir - Ritonavir - Indinavir - Nelfinavir
1. Acarbose 2. Miglitol

4. How do spare receptors effect the Km?
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
viral kinase
- ED 50 is less than the Km (less than 50% of receptors)
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

5. What is an occasional side effect of Aztreonam?
GI upset
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- ED 50 is less than the Km (less than 50% of receptors)
hypertension - angina - arrhythmias

6. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
- Glucagon
DHPG (dihydroxy-2- propoxymethyl guanine)
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
thick ascending limb

7. Preferential action of the Ca2+ channel blockers at cardiac muscle?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
hypertension - CHF - diabetic renal disease

8. Antimicrobial prophylaxis for Syphilis
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Modification via Acetylation
Benzathine penicillin G
- polymyxins

9. What are the Anti - TB drugs?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
ACE inhibitor.
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

10. For Warfarin What is the Duration of action
Chronic (weeks or months)
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

11. How would you treat African Trypanosomiasis (sleeping sickness)?
Suramin
INH: Injures Neurons and Hepatocytes
Headache - flushing - dyspepsia - blue - green color vision.
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

12. Which drug(s) cause this reaction: Fanconi's syndrome?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
- Tetracycline

13. Which drug(s) cause this reaction: Gingival hyperplasia?
No - warfarin - unlike heparin - can cross the placenta.
- Phenytoin
Foscarnet = pyroFosphate analog
1. Weight gain 2. Hepatotoxicity (troglitazone)

14. Which diuretics increase urine K+?
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.
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

15. Ethacrynic Acid - toxicity?
- Daunorubicin & Doxorubicin
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
blocks SR Ca2+ channels
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances

16. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
Keratin containing tissues - e.g. - nails
- Disulfram & also sulfonylureas - metronidazole
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Modification via Acetylation

17. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Pralidoxime regenerates active cholinesterase.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

18. Does Heparin have a long - medium - or short half life?
Ataxia - Dizziness - Slurred speech
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Short.

19. Furosemide increases the excretion of What ion?
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Ca2+ (Loops Lose calcium)
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium

20. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
It affects beta receptors equally and is used in AV heart block (rare).
Heparin catalyzes the activation of antithrombin III.
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Rheumatoid and osteoarthritis.

21. How is Vancomycin used clinically?
Used in combination therapy with SMZ to sequentially block folate synthesis
- Disulfram & also sulfonylureas - metronidazole
For serious - Gram + multidrug - resistant organisms
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.

22. What is combined with Ampicillin - Amoxicillin - Carbenicillin - Piperacillin - and Ticarcillin to enhance their spectrum?
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Clavulanic acid
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
- Dimercaprol - succimer

23. What is the MOA for the Tetracyclines?
competitive inhibirot of aldosterone in the cortical collecting tubule
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

24. Which diuretics increase urine NaCl?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
YES
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
all of them

25. For Heparin What is the Duration of action
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.
Acute (hours)
Pregnant women - Children; because animal studies show Damage to Cartilage
Binds ergosterol - Disrupts fungal membranes

26. Name the common Fluoroquinolones (6)
- NaHCO3
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

27. What are two processes Corticosteroids inhibit leading to decreased inflammation?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Competitive inibitor of progestins at progesterone receptors.
As an anticholinesterase it increases endogenous ACh and thus increases strength.

28. What is the category and mechanism of action of Zileuton in Asthma treatment?
Inhibit Ergosterol synthesis
- Protamine
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Antileukotriene; blocks synthesis by lipoxygenase.

29. Foscarnet does not require activation by a...
Quinidine - Amiodarone - Procainamide - Disopyramide
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
proximal convoluted tubule - thin descending limb - and collecting duct
viral kinase

30. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
Pretreat with antihistamines and a slow infusion rate
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Beta1 more than B2
Beta antagonist.

31. What is the mechanism of action of the H2 Blockers?
Ibuprofen - Naproxen - and Indomethacin
Reversible block of histamine H2 receptors
post MI and digitalis induced arrhythmias
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.

32. Which drug(s) cause this reaction: Pseudomembranous colitis?
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Neutropenia
- Clindamycin

33. List the specific antidote for this toxin: Heparin
- Clindamycin
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
- Protamine
atropine - homatropine - tropicamide

34. Procainamide - toxicity?
Amphetamine and Ephedrine
Binds ergosterol - Disrupts fungal membranes
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
reversible SLE- like syndrome

35. Are penicillinase resistant
CMV Retinitis in IC pts When Ganciclovir fails
Methicillin - Nafcillin - and Dicloxacillin
Interferes with microtubule function - disrupts mitosis - inhibits growth
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)

36. Adverse effects of Hydralazine?
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Minor hepatotoxicity - Drug interactions (activates P450)

37. What is the category of drug names ending in - zosin (e.g. Prazosin)
Alpha -1 antagonist
Vd= (Amt. of drug in body/ Plasma drug conc.)
Dopamine
Methicillin - Nafcillin - and Dicloxacillin

38. What is the clinical use for Clomiphene?
Treatment of infertility.
- Atropine & pralidoxime
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

39. Adverse effects of Nifedipine - verapamil?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
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.
dizziness - flushing - constipation (verapamil) - nausea
Interstitial nephritis

40. List the mechanism - clinical use - & toxicity of Prednisone.

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41. What is the category of drug names ending in - pril (e.g. Captopril)
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
AZT
ACE inhibitor.

42. What is the mechanism of action of Acetaminophen?
Interstitial nephritis
Useful in muscle paralysis during surgery or mechanical ventilation.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

43. What are common toxic side effects of Sulfonamides? (5)
Rifampin (DOC) - minocycline
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
- Penicillamine

44. Antiarrhythmic class IV- primary site of action?
AV nodal cells
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
DOC in diagnosing and abolishing AV nodal arrhythmias
severe hypertension - CHF

45. What is the mechanism of action of the thrombolytics?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
- Penicillamine
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
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.)

46. List the specific antidote for this toxin: Benzodiazepines
- Flumazenil
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Beta Blockers
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

47. As an Anes you want to use a depolarizing neuromuscular blocking drug on your pt - What do you use
Penicillin.
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Succinylcholine

48. What are Amantadine - associated side effects?
Ataxia - Dizziness - Slurred speech
severe hypertension - CHF
Nitrates
It inhibits release of NE.

49. Why does NE result in bradycardia?
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Acetylcholinesterase; ACh is broken down into choline and acetate.
No - hemicholinum block the uptake of Choline and thus Ach synthesis
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

50. What is the clinical use of Mifepristone (RU486)?
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Abortifacient.
Edrophonium