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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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 is the memory key for Metronidazole's clinical uses?
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Aminoglycosides - Tetracyclines
Tetracycline - Doxycycline - Demeclocycline - Minocycline
GET on the Metro

2. Why is Cilastatin administered with Imipenem?
Rifampin
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
AV nodal cells
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

3. MOA of Succinylcholine
1. Antiandrogen 2. Nausea 3. Vomiting
Prevents the release of Ca from SR of skeletal muscle
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Hydralazine and Minoxidil

4. Adverse effects of Reserpine?
sedation - depression - nasal stuffiness - diarrhea
No
1. Renal damage 2. Aplastic anemia 3. GI distress
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

5. Which RT inhibitors cause Lactic Acidosis?
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Nucleosides
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

6. Mannitol - mechanism?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
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.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

7. Name the common Fluoroquinolones (6)
Nephrotoxicity
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Captopril - Enalapril - Lisinopril

8. List the mechanism - clinical use - & toxicity of Paclitaxel.
penicillinase resistant
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Large anionic polymer - acidic
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

9. The COX-2 inhibitors (celecoxib - rofecoxib) have similar side effects to the NSAIDs with What one exception?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
- Physostigmine salicylate

10. List the specific antidote for this toxin: Copper
- Penicillamine
Aplastic anemia (dose independent) - Gray Baby Syndrome
Beta - lactam antibiotics
IV vitamin K and fresh frozen plasma

11. List the specific antidote for this toxin: Arsenic (all heavy metals)
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
- Dimercaprol - succimer
Blocks Norepi - but not Dopamine

12. What is combined with Ampicillin - Amoxicillin - Carbenicillin - Piperacillin - and Ticarcillin to enhance their spectrum?
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Clavulanic acid
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.

13. Antiarrhythmic class IV- clinical use?
prevention of nodal arrhythmias (SVT)
Mebendazole/Thiabendazole - Pyrantel Pamoate
- Penicillin
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods

14. What is the lab value used to monitor the effectiveness of Warfarin therapy?
collecting ducts
- Methylene blue
Rare.
The PT.

15. What are the clinical uses for 1st Generation Cephalosporins?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
severe hypertension - CHF
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
With an amino acid change of D- ala D- ala to D- ala D- lac

16. How is Vancomycin used clinically?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
For serious - Gram + multidrug - resistant organisms
Paranteral (IV - SC)
Gram + and Anerobes

17. What are two toxicities of the Sulfonylureas?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
TMP- SMZ
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

18. Reserpine will block the syntheis of this drug and but not its precursor.
Blocks Norepi - but not Dopamine
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

19. List the specific antidote for this toxin: Digitalis
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Benzodiazepine.
Cilastatin
- Normalize K+ - Lidocaine - & Anti - dig Mab

20. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Impairs the synthesis of vitamin K- dependent clotting factors
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Edrophonium

21. Which drug(s) cause this reaction: SLE- like syndrome?
- Hydralazine - Procainamide - INH - phenytoin
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
carbonic anhydrase inhibitors - K+ sparing diuretics
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

22. What microorganisms are Aminoglycosides ineffective against?
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Anaerobes
- Oxalic acid - Acidosis & nephrotoxicity
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

23. Which drug(s) cause this reaction: Hot flashes?
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- Atropine & pralidoxime
Captopril - Enalapril - Lisinopril
- Tamoxifen

24. What is the category of drug names ending in - azine (e.g. Chlorpromazine)
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
torsade de pointes
Phenothiazine (neuroleptic - antiemetic).
block Na+ channels in the cortical collecting tubule

25. For Heparin What is the Lab value to monitor
aPTT (intrinsic pathway)
Amphotericin B - Nystatin - Fluconazole/azoles
loop diuretics - spironolactone
Severe Gram - rod infections.

26. For Heparin What is the Duration of action
Potent immunosuppressive used in organ transplant recipients.
Ipratropium
Acute (hours)
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

27. Which cancer drugs work at the level of proteins(2)?
Useful in muscle paralysis during surgery or mechanical ventilation.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Cardiac glycoside (inotropic agent).
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

28. What is the MOA of Ganciclovir?
- Oxalic acid - Acidosis & nephrotoxicity
Captopril - Enalapril - Lisinopril
Inhibits CMV DNA polymerase
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

29. How are Sulfonamides employed clinically?
Gram + - Gram - - Norcardia - Chlamydia
Tendonitis and Tendon rupture
- EDTA - dimercaprol - succimer - & penicillamine
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

30. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Modification via Acetylation - Adenylation - or Phosphorylation
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
IV vitamin K and fresh frozen plasma

31. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Due to the presence of a bulkier R group
- Act on same receptor - Full has greater efficacy
Long.

32. Antiarrhythmic class II- toxicity?
anuria - CHF
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Polymyxin B - Polymyxin E

33. Resistance mechanisms for Chloramphenicol
Modification via Acetylation
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
TMP- SMZ (DOC) - aerosolized pentamidine
Succinylcholine

34. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
Carbenicillin - Piperacillin - and Ticarcillin
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Sulfonamides - Trimethoprim
Norepinephrine

35. Which drug(s) cause this reaction: Cutaneous flushing (4)?
- Niacin - Ca++ channel blockers - adenosine - vancomycin
distal convoluted tubule (early)
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Increase target cell response to insulin.

36. Antiarrhythmic class IB- effects?
edrophonium (extremely short acting anticholinesterase)
- Nitrate - hydroxocobalamin thiosulfate
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
cortical collecting tubule

37. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Hypersensitivity reactions
Methylxanthine.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

38. Name two classes of drugs for HIV therapy
Protease Inhibitors and Reverse Transcriptase Inhibitors
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
G6PD deficient individuals

39. Resistance mechanisms for Aminoglycosides
Activates antithrombin III
Modification via Acetylation - Adenylation - or Phosphorylation
- ACE inhibitors (Losartan>no cough)
Amphetamine and Ephedrine

40. Beta Blockers - CV toxicity?
Decreases synthesis of Mycolic Acid
Due to the presence of a bulkier R group
bradycardia - AV block - CHF
Pseudomembranous colitis (C. difficile) - fever - diarrhea

41. Can Warfarin be used during pregnancy?
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
No - warfarin - unlike heparin - can cross the placenta.
Acetylcholinesterase; ACh is broken down into choline and acetate.
Sildenafil fills the penis

42. What is the MOA for Ampicillin and Amoxicillin?
Dermatophytes (tinea - ringworm)
Ceftriaxone
Same as penicillin. Extended spectrum antibiotics
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)

43. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
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.
for RSV
Prevents the release of ACh - Which results in muscle paralysis.
Only in limited amounts

44. Cocaine shares is mechanism of action with What antidepressant
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.
- Aminocaproic acid
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
TCA

45. Which drug(s) cause this reaction: Oto and Nephrotoxicity (3)?
Sotalol - Ibutilide - Bretylium - Amiodarone
- Fluoroquinolones
Those patients who are taking nitrates.
- aminoglycosides - loop diuretics - cisplatin

46. Adverse effects of Hydralazine?
Carbenicillin - Piperacillin - and Ticarcillin
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

47. Mannitol - clinical use?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

48. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
proximal convoluted tubule
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

49. What can result due to antacid overuse?
Beta lactams - inhibit cell wall synthesis - Bactericidal
The PTT.
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Sotalol - Ibutilide - Bretylium - Amiodarone

50. What are the major structural differences between Penicillin and Cephalosporin?
Inhibits reabsorption of uric acid.
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.)
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)
Sotalol - Ibutilide - Bretylium - Amiodarone