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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. What is action of insulin in the liver - in muscle - and in adipose tissue?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Phenothiazine (neuroleptic - antiemetic).
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
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.

2. For Warfarin What is the Lab value to monitor
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
PT
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Intrathecally

3. What is a Ribavirin toxicity?
Inhibt Assembly of new virus by Blocking Protease Enzyme
Carbenicillin - Piperacillin - and Ticarcillin
Hemolytic anemia
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)

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

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5. What is Metronidazole combined with for 'triple therapy'? Against What organism?
- Chloramphenicol
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.)
Reversible block of histamine H2 receptors
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

6. What is the mechanism of action of the Sulfonylureas?
anuria - CHF
- Vitamin K & fresh frozen plasma
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
blocks SR Ca2+ channels

7. What are the Anti - TB drugs?
Teratogenic - Carcinogenic - Confusion - Headaches
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
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.

8. Name three Antiarrhythmic drugs in class IV.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Give an antichloinesterase - neostigmine - edrophonium - etc
Verapamil - Diltiazem - Bepridil

9. What is the category of drug names ending in - azine (e.g. Chlorpromazine)
Megaloblastic anemia - Leukopenia - Granulocytopenia
Phenothiazine (neuroleptic - antiemetic).
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

10. How does angiotensin II affect NE release?
- Formaldehyde & formic acid - severe acidosis & retinal damage
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
It acts presynaptically to increase NE release.
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

11. Describe first - order kinetics?
- Tricyclic antidepressants
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Constant FRACTION eliminated per unit time.(exponential)
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)

12. How is Ribavirin used clinically?
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
for RSV
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Carbachol - pilocarpine - physostigmine - echothiophate

13. What is the major toxic side effect of Penicillin?
Hypersensitivity reactions
Ibuprofen - Naproxen - and Indomethacin
- Vinca alkaloids(inhibit MT) - Paclitaxel
Activates antithrombin III

14. MOA: Block protein synthesis at 50s subunit
aPTT (intrinsic pathway)
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Captopril - Enalapril - Lisinopril
GI side effects. (Indomethacin is less toxic - more commonly used.)

15. What is the memory key for the action of Sildenafil (Viagra)?
hyperaldosteronism - K+ depletion - CHF
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Sildenafil fills the penis
Doxycycline - because it is fecally eliminated

16. List the mechanism - clinical use - & toxicity of 5 FU.
new arrhythmias - hypotension
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Keratin containing tissues - e.g. - nails

17. What are the clinical uses for Aztreonam?
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
Alpha -1 antagonist
AV nodal cells
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

18. Name two bile acid resins.
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
- Vinca alkaloids(inhibit MT) - Paclitaxel
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
cholestyramine - colestipol

19. What is the MOA for the Tetracyclines?
- Nitrate - hydroxocobalamin thiosulfate
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Cilastatin

20. For Heparin What is the Site of action
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
cortical collecting tubule
Nifedipine - Verapamil - Diltiazem
Blood

21. What is the memory key for the effect of magnesium hydroxide overuse?
Mg = Must go to the bathroom.
Interferes with microtubule function - disrupts mitosis - inhibits growth
Primaquine
Aminoglycosides

22. Beta Blockers - CV toxicity?
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
bradycardia - AV block - CHF
pulmonary edema - dehydration
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

23. Antimicrobial prophylaxis for a history of recurrent UTIs
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Cyclooxygenases (COX I - COX II).
Penicillin.
TMP- SMZ

24. What are four H2 Blockers?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Quinidine - Amiodarone - Procainamide - Disopyramide
G6PD deficient individuals

25. Sotalol - toxicity?
Pralidoxime regenerates active cholinesterase.
Erythromycin - Azithromycin - Clarithromycin
torsade de pointes - excessive Beta block
Antileukotriene; blocks leukotriene receptors.

26. Hydralazine - clinical use?
VACUUM your Bed Room'
severe hypertension - CHF
Erythromycin - Azithromycin - Clarithromycin
aPTT (intrinsic pathway)

27. What are three possible toxicities of NSAID usage?
1. Renal damage 2. Aplastic anemia 3. GI distress
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Fast vs. Slow Acetylators
- Tetracycline - amiodarone - sulfonamides

28. What is the category of drug names ending in - ane (e.g. Halothane)
Acetylcholine esterase
Digoxin=urinary Digitoxin=biliary
Inhalational general anesthetic.
Nitrates

29. What type of gout is treated with Allopurinol?
Chronic gout.
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
- Vitamin K & fresh frozen plasma
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

30. What anticholinesterase crosses the blood - brain - barrier?
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Vd= (Amt. of drug in body/ Plasma drug conc.)
physostigmine
Dermatophytes (tinea - ringworm)

31. What is the MOA for Rifampin?
Blood
Because they require some residual islet function.
Inhibits DNA dependent RNA polymerase
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

32. What should not be taken with Tetracyclines? / Why?
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
- Deferoxamine
loop diuretics - thiazides

33. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
Edrophonium
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Acts as a wide spectrum carbapenem

34. Which of epi - norepi - or isoproterenol results in bradycardia?
Norepinephrine
- Daunorubicin & Doxorubicin
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
cardiac depression - peripheral edema - flushing - dizziness - constipation

35. What are are the Sulfonylureas (general description) and What is their use?
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Pentamidine

36. How do Sulfonamides act on bacteria?
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
No - it inhibits the release of Nor Epi
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

37. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Acetylcholinesterase; ACh is broken down into choline and acetate.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Dopamine

38. What is Imipenem always administered with?
Cilastatin
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
edrophonium (extremely short acting anticholinesterase)
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT

39. What is the only depolarizing neuromuscular blocking agent?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Ibuprofen - Naproxen - and Indomethacin
Succinylcholine
Increases coumadin metabolism

40. Verapamil has similar action to?
Non - Nucleosides
Beta Blockers
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
anuria - CHF

41. For Warfarin What is the Site of action
Rheumatoid and osteoarthritis.
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Liver

42. Adverse effects of Nifedipine - verapamil?
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
dizziness - flushing - constipation (verapamil) - nausea
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
They inhibit reuptake of NE at the nerve terminal (as does cocaine).

43. What are the major toxic side effects of Imipenem/cilastatin?
GI distress - Skin rash - and Seizures at high plasma levels
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Blood

44. What is the MOA of the RT Inhibitors?
Hypersensitivity reactions
INH: Injures Neurons and Hepatocytes
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Used in combination therapy with SMZ to sequentially block folate synthesis

45. What are the clinical uses for Ticlopidine - Clopidogrel?
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Intrathecally
first dose orthostatic hypotension - dizziness - headache

46. What is the category of drug names ending in - olol (e.g. Propranolol)
Beta antagonist.
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

47. What drug is used during the pregnancy of an HIV+ mother? - Why?
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
AZT - to reduce risk of Fetal Transmission
Pentamidine

48. What is the clinical utility of clonidine?
Rare.
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Pralidoxime regenerates active cholinesterase.
Antileukotriene; blocks leukotriene receptors.

49. What is the clinical use for Nystatin?
block Na+ channels in the cortical collecting tubule
Protease inhibitor.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Topical and Oral - for Oral Candidiasis (Thrush)

50. What do Aminoglycosides require for uptake?
- Tricyclic antidepressants
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
Oxygen
- Vitamin K & fresh frozen plasma