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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. Resistance mechanisms for Tetracycline
Decreased uptake or Increased transport out of cell
PT
Inhibits CMV DNA polymerase
Edrophonium

2. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Prevents the release of Ca from SR of skeletal muscle
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Protease Inhibitors and Reverse Transcriptase Inhibitors

3. What is the category of drug names ending in - oxin (e.g. Digoxin)
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Cardiac glycoside (inotropic agent).

4. Antimicrobial prophylaxis for Syphilis
VACUUM your Bed Room'
Benzathine penicillin G
Foscarnet = pyroFosphate analog
- Corticosteroids - heparin

5. What are the major structural differences between Penicillin and Cephalosporin?
prevention of nodal arrhythmias (SVT)
- Methylene blue
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
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)

6. Reserpine will block the syntheis of this drug and but not its precursor.
1. Acarbose 2. Miglitol
Alpha -1 antagonist
Blocks Norepi - but not Dopamine
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

7. Acetazolamide - site of action?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
carbonic anhydrase inhibitors - K+ sparing diuretics
proximal convoluted tubule
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)

8. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
- Ethosuxamide - sulfonamides - lamotrigine

9. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
Butyrophenone (neuroleptic).
penicillinase resistant
Norepinephrine (Alpha1 -2 and beta 1)
competitive inhibirot of aldosterone in the cortical collecting tubule

10. What are the clinical uses for Ticlopidine - Clopidogrel?
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
hyperaldosteronism - K+ depletion - CHF
Norepinephrine

11. List the mechanism - clinical use - & toxicity of Paclitaxel.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Binding to the presynaptic alpha 2 release modulating receptors

12. What is the mechanism of action of Probenacid used to treat chronic gout?
Fast vs. Slow Acetylators
Pyridoxine (B6) administration
Gram + cocci - Gram - rods - and Anerobes
Inhibits reabsorption of uric acid.

13. Ca2+ channel blockers - site of action?
Cell membrane Ca2+ channels of cardiac sarcomere
physostigmine
Prevents the release of ACh - Which results in muscle paralysis.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.

14. List the specific antidote for this toxin: Methemoglobin
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
- Methylene blue
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Beta - lactamase cleavage of Beta - lactam ring

15. Which drug(s) cause this reaction: Aplastic anemia (5)?
Inhibit Ergosterol synthesis
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
- Clindamycin
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

16. Why is Cilastatin administered with Imipenem?
Used in combination therapy with SMZ to sequentially block folate synthesis
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Fast vs. Slow Acetylators
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

17. Procainamide - toxicity?
Chronic gout.
Severe Gram - rod infections.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
reversible SLE- like syndrome

18. Triamterene and amiloride - mechanism?
Albuterol - tertbutaline
1. Antiandrogen 2. Nausea 3. Vomiting
block Na+ channels in the cortical collecting tubule
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

19. What is Fluconazole specifically used for?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
loop diuretics - spironolactone
toxic
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

20. Which drug(s) cause this reaction: P450 inhibition(6)?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Rare.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

21. List the specific antidote for this toxin: Lead
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
- EDTA - dimercaprol - succimer - & penicillamine

22. Adverse effects of Hydrochlorothiazide?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Sotalol - Ibutilide - Bretylium - Amiodarone
GI discomfort
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

23. What enzyme does Zileuton inhibit?
Lipoxygenase
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
- Aminocaproic acid

24. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
Succinylcholine
Polymyxin B - Polymyxin E
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
torsade de pointes - excessive Beta block

25. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
fetal renal toxicity - hyperkalemia
Pseudomonas species and Gram - rods
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)

26. Specifically - How does Foscarnet inhibit viral DNA pol?
Penicillin.
Binds to the Pyrophosphate Binding Site of the enzyme
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

27. Cautions When using Amiodarone?
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
check PFTs - LFTs - and TFTs
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

28. Name four HMG- CoA reductase inhibitors.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
- Shifts the curve down - reduces Vmax
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

29. Furosemide - toxicity? (OH DANG)
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
- Cloazapine - carbamazapine - colchicine - PTU
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Albuterol - tertbutaline

30. What is a sign of toxicity with the use of thrombolytics?
Bleeding.
- Ammonium Chloride
Used in combination therapy with SMZ to sequentially block folate synthesis
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

31. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
reversible SLE- like syndrome
Stimulates beta adrenergic receptors
Cyclooxygenases (COX I - COX II).
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

32. Name the common Fluoroquinolones (6)
Antileukotriene; blocks synthesis by lipoxygenase.
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid

33. Which drug(s) cause this reaction: Cutaneous flushing (4)?
Prevents the release of Ca from SR of skeletal muscle
- Niacin - Ca++ channel blockers - adenosine - vancomycin
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
dry mouth - sedation - severe rebound hypertension

34. Name two classes of drugs for HIV therapy
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Protease Inhibitors and Reverse Transcriptase Inhibitors
- Isoniazid
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.

35. What is the category of drug names ending in - phylline (e.g. Theophylline)
- Vinca alkaloids(inhibit MT) - Paclitaxel
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.)
Dopamine; causes its release from intact nerve terminals
Methylxanthine.

36. What are three toxicities of Propylthiouracil?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Oral treatment of superficial infections

37. What are the major toxic side effects of Imipenem/cilastatin?
- Ethanol - dialysis - & fomepizole
Tetracycline - Doxycycline - Demeclocycline - Minocycline
- Atropine & pralidoxime
GI distress - Skin rash - and Seizures at high plasma levels

38. Explain differences between full and partial agonists(2).
Lipoxygenase
- Act on same receptor - Full has greater efficacy
first dose orthostatic hypotension - dizziness - headache
Short.

39. How is Ganciclovir activated?
Phosphorylation by a Viral Kinase
Methicillin - Nafcillin - and Dicloxacillin
- Steroids - Tamoxifen
- EDTA - dimercaprol - succimer - & penicillamine

40. What are Aminoglycosides synergistic with?
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Erectile dysfunction.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Beta - lactam antibiotics

41. What type of gout is treated with Probenacid?
Gram + cocci - Gram - rods - and Anerobes
Chronic gout.
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Penicillin.

42. What are two conditions in Which COX-2 inhibitors might be used?
compensatory tachycardia - fluid retention - lupus - like syndrome
- ACE inhibitors (Losartan>no cough)
Megaloblastic anemia - Leukopenia - Granulocytopenia
Rheumatoid and osteoarthritis.

43. What is combination TMP- SMZ used to treat?
Inhibits Viral DNA polymerase
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
- Clindamycin
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

44. Sotalol - toxicity?
Nitrates
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
torsade de pointes - excessive Beta block
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol

45. How is Acyclovir used clinically?
- Shifts the curve down - reduces Vmax
- Tetracycline
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
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.

46. Ryanodine - site of action?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
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
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
blocks SR Ca2+ channels

47. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
Dopamine
compensatory tachycardia - fluid retention - lupus - like syndrome
As an anticholinesterase it increases endogenous ACh and thus increases strength.
ACE inhibitor.

48. Furosemide - clinical use?
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Delirium - Tremor - Nephrotoxicity
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

49. What are two clinical uses of Azathioprine?
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
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
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
ACIDazolamide' causes acidosis

50. What are two Glitazones?
1. Pioglitazone 2. Rosiglitazone.
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.
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
YES