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. What is the difference in receptor affinity of epinephrine at low doses? High doses?

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

2. Ca2+ channel blockers - mechanism?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
- Fluoroquinolones
- Penicillin
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility

3. What conditions are treated with Metronidazole?
Babiturate.
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Digitoxin 70% Digoxin 20-40%
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas

4. How does a noncompetitive antagonist effect an agonist?
- Shifts the curve down - reduces Vmax
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Norepinephrine (Alpha1 -2 and beta 1)
Binds ergosterol - Disrupts fungal membranes

5. What are are the Sulfonylureas (general description) and What is their use?
AZT - to reduce risk of Fetal Transmission
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

6. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Inhibits cell wall mucopeptide formation - Bactericidal
Same as penicillin. Extended spectrum antibiotics
Teratogenic - Carcinogenic - Confusion - Headaches
very short acting

7. What populations are Floroquinolones contraindicated in? Why?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Pregnant women - Children; because animal studies show Damage to Cartilage
Lidocaine - Mexiletine - Tocainide
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.

8. What is the lab value used to monitor the effectiveness of Heparin therapy?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
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.
Fast vs. Slow Acetylators
The PTT.

9. Acetazolamide - clinical uses?
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
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Captopril - Enalapril - Lisinopril
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness

10. Which drug(s) cause this reaction: Photosensitivity(3)?
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
Long.
Doxycycline - because it is fecally eliminated
- Tetracycline - amiodarone - sulfonamides

11. List the mechanism - clinical use - & toxicity of Tamoxifen.
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Pseudomonas species and Gram - rods
all of them

12. What are two processes Corticosteroids inhibit leading to decreased inflammation?
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
all of them
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes

13. What antimuscarinic agent is used in asthma and COPD?
Methicillin - Nafcillin - and Dicloxacillin
Modification via Acetylation
Ipratropium
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

14. Antiarrhythmic class IB- effects?
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
- Methotrexate - 5 FU - 6 mercaptopurine
Lipoxygenase
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

15. Which RT inhibitor causes Megaloblastic Anemia?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
pulmonary edema - dehydration
Antifungal.
AZT

16. Which drug(s) cause this reaction: Atropine - like side effects?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
- Tricyclic antidepressants

17. What is a prerequisite for Acyclovir activation?
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
It must be Phosphorylated by Viral Thymidine Kinase
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
first dose orthostatic hypotension - dizziness - headache

18. Common toxicities associated with Griseofulvin?
Teratogenic - Carcinogenic - Confusion - Headaches
Dopamine; causes its release from intact nerve terminals
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

19. Amprotericin B ___________ the BBB
Only in limited amounts
Does not cross
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
- Tetracycline

20. What is the effect of guanethidine on adrenergic NE release?
It inhibits release of NE.
dry mouth - sedation - severe rebound hypertension
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Pentavalent Antimony

21. ACE inhibitors - toxicity?
Polymyxin B - Polymyxin E
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Decreases synthesis of Mycolic Acid
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.

22. What is the clinical use of Mifepristone (RU486)?
Abortifacient.
Na/K ATPase
- Vitamin K & fresh frozen plasma
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

23. What are two conditions in Which COX-2 inhibitors might be used?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
- Shifts the curve to the right - increases Km
Long.
Rheumatoid and osteoarthritis.

24. What is the memory key involving the '4 R's of Rifampin?'
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Saquinavir - Ritonavir - Indinavir - Nelfinavir
TMP- SMZ (DOC) - aerosolized pentamidine

25. What is the formula for Clearance (CL)
CL= (rate of elimination of drug/ Plasma drug conc.)
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
IV vitamin K and fresh frozen plasma
ACIDazolamide' causes acidosis

26. What is the MOA of Amantadine?
Choline acetyltransferase
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

27. What enzyme does Zileuton inhibit?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Gram + - Gram - - Norcardia - Chlamydia
Lipoxygenase
Tendonitis and Tendon rupture

28. What are the products and their toxicities of the metabolism of Ethylene Glycol by / alcohol dehydrogenase?
- Oxalic acid - Acidosis & nephrotoxicity
hypertension - CHF - diabetic renal disease
TMP- SMZ (DOC) - aerosolized pentamidine
Pentavalent Antimony

29. ACE inhibitors - mechanism?
Pretreat with antihistamines and a slow infusion rate
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Same as penicillin. Extended spectrum antibiotics

30. What are signs of Sildenafil (Viagra) toxicity?
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
cholestyramine - colestipol
Blocks Norepi - but not Dopamine
Headache - flushing - dyspepsia - blue - green color vision.

31. Mannitol - site of action?
Beta Blockers
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
proximal convoluted tubule - thin descending limb - and collecting duct
Disulfiram - like reaction with EtOH - Headache

32. What beta 2 agonist will help your 21yo Astma pt?
Albuterol - tertbutaline
Aminoglycosides - Tetracyclines
Tricyclic antidepressant.
Pretreat with antihistamines and a slow infusion rate

33. Adenosine - clinical use?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Yes
DOC in diagnosing and abolishing AV nodal arrhythmias

34. Does Heparin have a long - medium - or short half life?
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
- Methotrexate - 5 FU - 6 mercaptopurine
Cell membrane Ca2+ channels of cardiac sarcomere
Short.

35. What is the MOA for the Azoles?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
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.
Tendonitis and Tendon rupture
Inhibit Ergosterol synthesis

36. What are two mechanisms of action of Propythiouracil?
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
- Penicillamine
Sulfonamides - Trimethoprim

37. Resistance mechanisms for Vancomycin
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Same as penicillin. Extended spectrum antibiotics
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity

38. What do Aminoglycosides require for uptake?
1. Pioglitazone 2. Rosiglitazone.
Pentavalent Antimony
Rifampin (DOC) - minocycline
Oxygen

39. How do we stop angina?
PT
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

40. ACE inhibitors - clinical use?
INH: Injures Neurons and Hepatocytes
- Act on same receptor - Full has greater efficacy
hypertension - CHF - diabetic renal disease
severe hypertension - CHF

41. What are two Alpha - glucosidase inhibitors?
Protamine sulfate
1. Acarbose 2. Miglitol
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Bleeding.

42. What drug is used to diagnose myasthenia gravis?
edrophonium (extremely short acting anticholinesterase)
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
CMV - esp in Immunocompromised patients
- Tetracycline

43. What is the most common cause of Pt noncompliance with Macrolides?
Teratogenic - Carcinogenic - Confusion - Headaches
RESPIre
GI discomfort
loop diuretics - thiazides

44. What is combination TMP- SMZ used to treat?
propanolol - esmolol - metoprolol - atenolol - timolol
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Neutropenia

45. List the mechanism - clinical use - & toxicity of Vincristine.

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

46. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
post MI and digitalis induced arrhythmias
Chronic anticoagulation.
Pseudomonas species and Gram - rods

47. Which drug(s) cause this reaction: Osteoporosis (2)?
Liver
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
- Corticosteroids - heparin

48. What is the MOA for the Cephalosporins?
Beta lactams - inhibit cell wall synthesis - Bactericidal
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Pseudomonas species and Gram - rods
Because they require some residual islet function.

49. List the specific antidote for this toxin: Beta Blockers
Digitoxin>95% Digoxin 75%
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- Corticosteroids - heparin
- Glucagon

50. Classes of antihypertensive drugs?
not a sulfonamide - but action is the same as furosemide
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Megaloblastic anemia - Leukopenia - Granulocytopenia
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors