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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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1. Name the Protease Inhibitors (4)
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Inhibits Viral DNA polymerase
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Foscarnet = pyroFosphate analog

2. What is the mechanism of action of Misoprostol?
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
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.

3. Preferential action of the Ca2+ channel blockers at cardiac muscle?
- N- acetylcystine
Beta -2 agonist.
Spironolactone - Triamterene - Amiloride (the K+ STAys)
cardiac muscle: Verapamil>Diltiazem>Nifedipine

4. Which RT inhibitors cause a Rash?
Non - Nucleosides
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.
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

5. ADH antagonists - site of action?
Pretreat with antihistamines and a slow infusion rate
Fast vs. Slow Acetylators
collecting ducts
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers

6. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
- Clindamycin
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
RESPIre
Norepinephrine

7. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
Pretreat with antihistamines and a slow infusion rate
Oxygen
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Bethanechol - Neostigmine - physostigmine

8. Name three Antiarrhythmic drugs in class IC.
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
AZT - to reduce risk of Fetal Transmission
Flecainide - Encainide - Propafenone
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole

9. Which drug(s) cause this reaction: Adrenocortical Insufficiency
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
Foscarnet = pyroFosphate analog
Imipenem
- Glucocorticoid withdrawal

10. List the mechanism - clinical use - & toxicity of Methotrexate.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Pyridoxine (B6) administration
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

11. Adverse effects of ganglionic blockers?
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction

12. Clinical use of Isoniazid (INH)?
Decreased uptake or Increased transport out of cell
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB

13. What is Fluconazole specifically used for?
Nucleosides
Quinidine - Amiodarone - Procainamide - Disopyramide
Large anionic polymer - acidic
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

14. What are common side effects of Amphotericin B?
Due to the presence of a bulkier R group
The PT.
Malaria (P. falciparum)
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

15. These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Large anionic polymer - acidic
Amphetamine and Ephedrine

16. What is the clinical utility of cocaine?
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
The only local anesthetic with vasoconstrictive properties.
- Penicillin

17. How is Trimethoprim used clinically?
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Used in combination therapy with SMZ to sequentially block folate synthesis
INH: Injures Neurons and Hepatocytes
Pseudomonas species and Gram - rods

18. What are the clinical uses for 2nd Generation Cephalosporins?
Aminoglycosides - Tetracyclines
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
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.
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

19. What is the lab value used to monitor the effectiveness of Warfarin therapy?
Sotalol - Ibutilide - Bretylium - Amiodarone
1. Antiandrogen 2. Nausea 3. Vomiting
post MI and digitalis induced arrhythmias
The PT.

20. What are the Macrolides used for clinically?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
YES

21. What is the MOA for the Azoles?
decrease
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
Inhibit Ergosterol synthesis
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

22. Cautions When using Amiodarone?
Potent immunosuppressive used in organ transplant recipients.
Useful in muscle paralysis during surgery or mechanical ventilation.
check PFTs - LFTs - and TFTs
Diarrhea

23. What microorganisms are Aminoglycosides ineffective against?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Anaerobes
Polymyxin B - Polymyxin E
ACIDazolamide' causes acidosis

24. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
hyperaldosteronism - K+ depletion - CHF
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Carbachol - pilocarpine - physostigmine - echothiophate

25. How is Amphotericin B administered for fungal meningitis?
Indomethacin is used to close a patent ductus arteriosus.
1. Renal damage 2. Aplastic anemia 3. GI distress
Intrathecally
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

26. Spironolactone - mechanism?
- Vinca alkaloids(inhibit MT) - Paclitaxel
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
- Ammonium Chloride
competitive inhibirot of aldosterone in the cortical collecting tubule

27. What is Clindamycin used for clinically?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Triple sulfas or SMZ
distal convoluted tubule (early)
bradycardia - AV block - CHF

28. What Sulfonamides are used for simple UTIs?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
loop diuretics - spironolactone
Triple sulfas or SMZ
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

29. How do spare receptors effect the Km?
post MI and digitalis induced arrhythmias
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Polymyxins
- ED 50 is less than the Km (less than 50% of receptors)

30. What type of neurological blockade would hexamethonium create?
Bleeding.
CL= (rate of elimination of drug/ Plasma drug conc.)
Inhibit Ergosterol synthesis
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

31. Amiodarone - toxicity?
Used in combination therapy with SMZ to sequentially block folate synthesis
Leukotrienes increasing bronchial tone.
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail

32. What are Aminoglycosides synergistic with?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Beta - lactam antibiotics

33. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
distal convoluted tubule (early)
G6PD deficient individuals

34. What are four conditions in Which H2 Blockers are used clinically?
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Does not cross
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

35. Specifically - How does Foscarnet inhibit viral DNA pol?
Binds to the Pyrophosphate Binding Site of the enzyme
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Megaloblastic anemia - Leukopenia - Granulocytopenia
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

36. What effect would atropine have on the preganglionic sympathetic activation of sweat glands? Would this person sweat?
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
- Shifts the curve down - reduces Vmax
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Teratogenic - Carcinogenic - Confusion - Headaches

37. Explain pH dependent urinary drug elimination?
Beta lactams - inhibit cell wall synthesis - Bactericidal
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
- Phenytoin
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

38. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Keratin containing tissues - e.g. - nails
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Pseudomonas species and Gram - rods

39. In coma situations you rule out What (7)?

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40. Is resistant to penicillinase?
Prevents the release of Ca from SR of skeletal muscle
DOC in diagnosing and abolishing AV nodal arrhythmias
decrease conduction velocity - increase ERP - increase PR interval
Imipenem

41. For Heparin What is the Mechanism of action
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
scopolamine
Activates antithrombin III
Norepinephrine

42. Mannitol - clinical use?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Keratin containing tissues - e.g. - nails
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

43. Antiarrhythmic class II- toxicity?
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
torsade de pointes
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia

44. Which drug(s) cause this reaction: Cough?
- ACE inhibitors (Losartan>no cough)
very short acting
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
cardiac depression - peripheral edema - flushing - dizziness - constipation

45. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Bacitracin - Vancomycin
Same as penicillin. Extended spectrum antibiotics
- Shifts the curve to the right - increases Km
Beta - lactamase cleavage of Beta - lactam ring

46. Ca2+ channel blockers - mechanism?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
distal convoluted tubule (early)
Leukotrienes increasing bronchial tone.
Tetracycline - Doxycycline - Demeclocycline - Minocycline

47. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
reversible SLE- like syndrome
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
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.
cholestyramine - colestipol

48. Antiarrhythmic class IB- clinical uses?
post MI and digitalis induced arrhythmias
new arrhythmias - hypotension
With supplemental Folic Acid
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

49. Adverse effect of Nitroprusside?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
cyanide toxicity (releases CN)

50. Antiarrhythmic class IB- effects?
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Ceftriaxone