Test your basic knowledge |

USMLE Step 1 Pharmacology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. Does Heparin have a long - medium - or short half life?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Short.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

2. Name two bile acid resins.
dizziness - flushing - constipation (verapamil) - nausea
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Carbenicillin - Piperacillin - and Ticarcillin
cholestyramine - colestipol

3. MOA: Block mRNA synthesis
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Beta antagonist.
Rifampin
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.

4. ________ ae not resistant to penicillinase - - but they are less susceptible than the other Beta lactams
Used in combination therapy with SMZ to sequentially block folate synthesis
Cephalosporins
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
BM suppression (neutropenia - anemia) - Peripheral neuropathy

5. Cautions When using Amiodarone?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Edrophonium
Slow - limited by half lives of clotting factors
check PFTs - LFTs - and TFTs

6. Loop diuretics (furosemide)- site of action?
Digitoxin>95% Digoxin 75%
thick ascending limb
1. Weight gain 2. Hepatotoxicity (troglitazone)
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

7. What is the mechanism of action of Allopurinol used to treat chronic gout?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

8. Hydralazine - clinical use?
severe hypertension - CHF
Chronic gout.
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
- Tricyclic antidepressants

9. What is the specific clinical use of Indomethacin in neonates?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Indomethacin is used to close a patent ductus arteriosus.
Sildenafil fills the penis
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

10. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
AZT - to reduce risk of Fetal Transmission
Na/K ATPase
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

11. How are the Latent Hypnozoite (Liver) forms of Malaria (P. vivax - P.ovale) treated?
Penicillin.
Nevirapine - Delavirdine
Verapamil - Diltiazem - Bepridil
Primaquine

12. Thiazides - site of action?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
distal convoluted tubule (early)
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Activates antithrombin III

13. Which drug(s) cause this reaction: Adrenocortical Insufficiency
Vd= (Amt. of drug in body/ Plasma drug conc.)
- Glucocorticoid withdrawal
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

14. Adverse effect of Nitroprusside?
cyanide toxicity (releases CN)
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Quinidine - Amiodarone - Procainamide - Disopyramide

15. What is the clinical use of Mifepristone (RU486)?
Only in limited amounts
Abortifacient.
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

16. Name the common Azoles
Doxycycline - because it is fecally eliminated
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
- Phenytoin

17. Adverse effects of Hydrochlorothiazide?
Yes
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Penicillin.
Captopril - Enalapril - Lisinopril

18. What are three clinical uses of the NSAIDs?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Forms toxic metabolites in the bacterial cell - Bactericidal
Quinidine - Amiodarone - Procainamide - Disopyramide
Premature infants - because they lack UDP- glucuronyl transferase

19. What is the mechanism of action of Omeprazole - Lansoprazole?
Chronic anticoagulation.
atropine - homatropine - tropicamide
- Hydralazine - Procainamide - INH - phenytoin
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

20. Adverse effects of Loop Diuretics?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Mg = Must go to the bathroom.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

21. What are three common NSAIDS other than Aspirin?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
viral kinase
Hypersensitivity reactions
Ibuprofen - Naproxen - and Indomethacin

22. Mnemonic for Foscarnet?
Foscarnet = pyroFosphate analog
These B-2 agonists cause respiratory smooth muscle to relax.
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Binds to the Pyrophosphate Binding Site of the enzyme

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

24. How do we stop angina?
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
competitive inhibirot of aldosterone in the cortical collecting tubule

25. Name two LPL stimulators.
Gemfibrozil - Clofibrate
- ED 50 is less than the Km (less than 50% of receptors)
Paranteral (IV - SC)
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)

26. What is the category and mechanism of action of Zileuton in Asthma treatment?
Same as penicillin. Extended spectrum antibiotics
Antileukotriene; blocks synthesis by lipoxygenase.
PT
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail

27. Why would dopamine be useful in treating shock?
Beta Blockers
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Anaerobes
- Shifts the curve down - reduces Vmax

28. What effect would atropine have on a patient with peptic ulcer disease?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
loop diuretics - spironolactone
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

29. Ca2+ channel blockers - site of action?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Keratin containing tissues - e.g. - nails
Epinephirine(Alpha1 -2 and Beta 1 -2)
Cell membrane Ca2+ channels of cardiac sarcomere

30. What is the clinical use for Nystatin?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
- Atropine & pralidoxime
Topical and Oral - for Oral Candidiasis (Thrush)

31. For Warfarin What is the Mechanism of action
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Impairs the synthesis of vitamin K- dependent clotting factors
They inhibit reuptake of NE at the nerve terminal (as does cocaine).

32. What is the category of drug names ending in - tropin (e.g. Somatotropin)
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Pituitary hormone.
GI disturbances.

33. What is the mechanism of action of the Sulfonylureas?
- Glucagon
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
not a sulfonamide - but action is the same as furosemide
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

34. What is the mechanism of action of Probenacid used to treat chronic gout?
Inhibits reabsorption of uric acid.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Tetracycline - Doxycycline - Demeclocycline - Minocycline
new arrhythmias - hypotension

35. What organisms does Griseofulvin target?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Dermatophytes (tinea - ringworm)
Those patients who are taking nitrates.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

36. What are three complications of Warfarin usage?
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

37. Adverse effects of Losartan?
GI distress - Skin rash - and Seizures at high plasma levels
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
fetal renal toxicity - hyperkalemia
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

38. List the specific antidote for this toxin: Anticholinesterases (organophosphate.)
compensatory tachycardia - fluid retention - lupus - like syndrome
very short acting
Megaloblastic anemia - Leukopenia - Granulocytopenia
- Atropine & pralidoxime

39. What is the category of drug names ending in - azine (e.g. Chlorpromazine)
Phenothiazine (neuroleptic - antiemetic).
Nitrates
Inhibit viral DNA polymerase
Methicillin - Nafcillin - and Dicloxacillin

40. What is the category of drug names ending in - ipramine (e.g. Imipramine)
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
Tricyclic antidepressant.
competitive inhibirot of aldosterone in the cortical collecting tubule
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

41. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
- Steroids - Tamoxifen
Norepinephrine
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

42. List the specific antidote for this toxin: Copper
Systemic mycoses
- Penicillamine
Blood
Beta adrenergic receptors and Ca2+ channels (stimulatory)

43. MOA: Block nucleotide synthesis
sedation - sleep alterations
Sulfonamides - Trimethoprim
amphetamine and ephedrine
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

44. What drug is used during the pregnancy of an HIV+ mother? - Why?
Bethanechol - Neostigmine - physostigmine
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
AZT - to reduce risk of Fetal Transmission
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

45. Which drug(s) cause this reaction: Hepatitis?
Because they require some residual islet function.
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
- Isoniazid
AV nodal cells

46. List the specific antidote for this toxin: Benzodiazepines
Cardiac glycoside (inotropic agent).
- Flumazenil
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Inhibit viral DNA polymerase

47. Name two classes of drugs for HIV therapy
These B-2 agonists cause respiratory smooth muscle to relax.
Rheumatoid and osteoarthritis.
Protease Inhibitors and Reverse Transcriptase Inhibitors
Praziquantel

48. What is the memory key involving the '4 R's of Rifampin?'
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Polymyxins
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

49. Classes of antihypertensive drugs?
sedation - positive Coombs' test
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Pseudomembranous colitis (C. difficile) - fever - diarrhea

50. List the specific antidote for this toxin: Salicylates
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
- Alkalinize urine & dialysis
dry mouth - sedation - severe rebound hypertension