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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. Preferential action of the Ca2+ channel blockers at cardiac muscle?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Penicillin.

2. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
Pretreat with antihistamines and a slow infusion rate
Hypersensitivity reactions
- Tamoxifen
Suramin

3. Digoxin v. Digitoxin: bioavailability?
Inhibits reabsorption of uric acid.
Digitoxin>95% Digoxin 75%
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Digoxin=urinary Digitoxin=biliary

4. List the mechanism - clinical use - & toxicity of Busulfan.
Blood
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
cross - allergenic
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

5. For Heparin What is the Ability to inhibit coagulation in vitro
Chronic anticoagulation.
Yes
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
proarrhythmic

6. For Heparin What is the Structure
cyanide toxicity (releases CN)
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Inhibt Assembly of new virus by Blocking Protease Enzyme
Large anionic polymer - acidic

7. Can Warfarin be used during pregnancy?
Anaerobes
No - warfarin - unlike heparin - can cross the placenta.
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

8. List the specific antidote for this toxin: Arsenic (all heavy metals)
- Steroids - Tamoxifen
- Quinidine - quinine
Same as penicillin. Extended spectrum antibiotics
- Dimercaprol - succimer

9. Adverse effects of Clonidine?
torsade de pointes - excessive Beta block
Nevirapine - Delavirdine
No - hemicholinum block the uptake of Choline and thus Ach synthesis
dry mouth - sedation - severe rebound hypertension

10. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Antifungal.
Potent immunosuppressive used in organ transplant recipients.
Same as penicillin. Act as narrow spectrum antibiotics

11. What is the category and mechanism of action of Zafirlukast in Asthma treatment?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Antileukotriene; blocks leukotriene receptors.
Protease Inhibitors and Reverse Transcriptase Inhibitors
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.

12. What is the category of drug names ending in - zosin (e.g. Prazosin)
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
With supplemental Folic Acid
Alpha -1 antagonist

13. What are the side effects of Rifampin?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
- Corticosteroids - heparin
Minor hepatotoxicity - Drug interactions (activates P450)
Gemfibrozil - Clofibrate

14. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
Norepinephrine (Alpha1 -2 and beta 1)
Cephalosporins
With an amino acid change of D- ala D- ala to D- ala D- lac
sedation - depression - nasal stuffiness - diarrhea

15. Which RT inhibitors cause a Rash?
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
Hypersensitivity reactions
Activates antithrombin III
Non - Nucleosides

16. What is the effect of norepinephrine on bp and pulse pressure?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
Rifampin (DOC) - minocycline

17. What are three possible complications of Heparin therapy?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Pituitary hormone.
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
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

18. What do Aminoglycosides require for uptake?
Buy AT 30 - CELL at 50'
Bleeding.
Oxygen
Cephalosporins

19. Which drug(s) cause this reaction: Osteoporosis (2)?
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
ACIDazolamide' causes acidosis
- Corticosteroids - heparin
1. Acarbose 2. Miglitol

20. What class of drug is echothiophate? What is its indication?
Nucleosides
anticholinesterase glaucoma
severe hypertension - CHF
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

21. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
Staphlococcus aureus
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
post MI and digitalis induced arrhythmias
Inhibits reabsorption of uric acid.

22. Why would you use pralidoxime after exposure to an organophosphate?
Pralidoxime regenerates active cholinesterase.
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
- Glucocorticoid withdrawal
Suramin

23. ________ ae not resistant to penicillinase - - but they are less susceptible than the other Beta lactams
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Cephalosporins
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

24. What is used to reverse the action of Heparin?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).

25. What are the clinical uses for Imipenem/cilastatin?
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
TMP- SMZ (DOC) - aerosolized pentamidine
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Gram + cocci - Gram - rods - and Anerobes

26. Which drug(s) cause this reaction: G6PD hemolysis(8)?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
AmOxicillin has greater Oral bioavailability
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.

27. For Warfarin What is the Route of administration
H2 antagonist
hypertension - angina - arrhythmias
Oral
Nitrates

28. What is the category of drug names ending in - pril (e.g. Captopril)
ACE inhibitor.
Flecainide - Encainide - Propafenone
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.

29. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Lidocaine - Mexiletine - Tocainide
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Digitoxin>95% Digoxin 75%

30. What is Clindamycin used for clinically?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Beta lactams - inhibit cell wall synthesis - Bactericidal
Ataxia - Dizziness - Slurred speech
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

31. What is a prerequisite for Acyclovir activation?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
effective in torsade de pointes and digoxin toxicity
It must be Phosphorylated by Viral Thymidine Kinase
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

32. What is the major side effect for Ampicillin and Amoxicillin?
Hypersensitivity reactions
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
- Corticosteroids - heparin
Onchocerciasis ('river blindness'-- rIVER- mectin)

33. How is Rifampin used clinically?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
toxic
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.

34. How is Acyclovir used clinically?
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
sedation - positive Coombs' test
Mebendazole/Thiabendazole - Pyrantel Pamoate
Inhibition of 50S peptidyl transferase - Bacteriostatic

35. In What population does Gray Baby Syndrome occur? Why?
Liver
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.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Premature infants - because they lack UDP- glucuronyl transferase

36. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Slow - limited by half lives of clotting factors
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
Chronic gout.

37. What are the Macrolides used for clinically?
hypertension - CHF - diabetic renal disease
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

38. How is Leishmaniasis treated?
Rare.
Pentavalent Antimony
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

39. Nifedipine has similar action to?
Nitrates
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
CMV Retinitis in IC pts When Ganciclovir fails

40. What is the category of drug names ending in - oxin (e.g. Digoxin)
Neomycin
Cardiac glycoside (inotropic agent).
- ED 50 is less than the Km (less than 50% of receptors)
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness

41. Isopoterenol was given to a patient with a developing AV block - why?
Edrophonium
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Stimulates beta adrenergic receptors
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

42. Which diuretics cause alkalosis?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Polymyxin B - Polymyxin E
Carbachol - pilocarpine - physostigmine - echothiophate
loop diuretics - thiazides

43. Which individuals are predisposed to Sulfonamide - induced hemolysis?
G6PD deficient individuals
CL= (rate of elimination of drug/ Plasma drug conc.)
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Carbachol - pilocarpine - physostigmine - echothiophate

44. Amiodarone - toxicity?
Hypersensitivity reactions
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
- Nitrate - hydroxocobalamin thiosulfate
TMP- SMZ

45. What type of gout is treated with Probenacid?
Chronic gout.
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
GI discomfort
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation

46. ACE inhibitors - toxicity?
Erythromycin - Azithromycin - Clarithromycin
TMP- SMZ
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

47. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Inhibits Viral DNA polymerase
Same as penicillin. Extended spectrum antibiotics
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions

48. What is the MOA of Griseofulvin?
Beta lactams - inhibit cell wall synthesis - Bactericidal
depresses ectopic pacemakers - especially in digoxin toxicity
Interferes with microtubule function - disrupts mitosis - inhibits growth
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

49. Furosemide - clinical use?
Diuresis in pateints with sulfa allergy
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Peptic ulcer disease.

50. What antimuscarinic agent is used in asthma and COPD?
Short.
GI upset
Ipratropium
Megaloblastic anemia - Leukopenia - Granulocytopenia