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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. For Heparin What is the Site of action
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Blood
Used in combination therapy with SMZ to sequentially block folate synthesis
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

2. Name three Antiarrhythmic drugs in class IC.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Flecainide - Encainide - Propafenone
compensatory tachycardia - fluid retention - lupus - like syndrome
- Antipsychotics

3. What is Niclosamide used for?
- Penicillamine
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Pregnant women - Children; because animal studies show Damage to Cartilage

4. Which drug(s) cause this reaction: Cutaneous flushing (4)?
Nucleosides
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

5. Which drug(s) cause this reaction: SLE- like syndrome?
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
- Hydralazine - Procainamide - INH - phenytoin
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Digitoxin 70% Digoxin 20-40%

6. What conditions would you use dantrolene?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

7. List the specific antidote for this toxin: Copper
- Alkalinize urine & dialysis
Fast vs. Slow Acetylators
proximal convoluted tubule
- Penicillamine

8. What is the mechanism of action of Omeprazole - Lansoprazole?
Foscarnet = pyroFosphate analog
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Alpha -1 antagonist

9. What are two toxicities of the Sulfonylureas?
thiazides - amiloride
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

10. What is a common side effect of Misoprostol?
- Fluoroquinolones
depresses ectopic pacemakers - especially in digoxin toxicity
Diarrhea
Inhibits CMV DNA polymerase

11. Antiarrhythmic class IV- toxicity?
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Resistant Gram - infections
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

12. What drugs target anticholinesterase
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
- ACE inhibitors (Losartan>no cough)
- Fluoroquinolones
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

13. Cocaine casues vasoconstriction and local anesthesia by What mechanism
For serious - Gram + multidrug - resistant organisms
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Indirect agonist - uptake inhibitor
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

14. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
Reversible block of histamine H2 receptors
YES
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Pituitary hormone.

15. Toxic effects of TMP include?
Delirium - Tremor - Nephrotoxicity
Choline acetyltransferase
viral kinase
Megaloblastic anemia - Leukopenia - Granulocytopenia

16. What is the MOA for the Tetracyclines?
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Inhibits DNA dependent RNA polymerase
Methicillin - Nafcillin - and Dicloxacillin
- Ethosuxamide - sulfonamides - lamotrigine

17. List the mechanism - clinical use - & toxicity of Tamoxifen.
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

18. What are four conditions in Which H2 Blockers are used clinically?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
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.

19. Esmolol - short or long acting?
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Inhibits Viral DNA polymerase
- Penicillin
very short acting

20. What are Polymyxins used for?
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.)
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Resistant Gram - infections
reversible SLE- like syndrome

21. What are three possible complications of Heparin therapy?
- ACE inhibitors (Losartan>no cough)
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
cardiac muscle: Verapamil>Diltiazem>Nifedipine
DHPG (dihydroxy-2- propoxymethyl guanine)

22. Which antimuscarinic agents are used in producing mydriasis and cycloplegia?
atropine - homatropine - tropicamide
Diuresis in pateints with sulfa allergy
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Hypersensitivity reactions

23. List five common glucocorticoids.
not a sulfonamide - but action is the same as furosemide
Headache - flushing - dyspepsia - blue - green color vision.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

24. Ethacrynic Acid - clinical use?
Diuresis in pateints with sulfa allergy
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
1. Weight gain 2. Hepatotoxicity (troglitazone)
Beta adrenergic receptors and Ca2+ channels (stimulatory)

25. MOA: Disrupt fungal cell membranes
- Daunorubicin & Doxorubicin
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Competitive inibitor of progestins at progesterone receptors.
Amphotericin B - Nystatin - Fluconazole/azoles

26. How does dantrolene work?
Increase target cell response to insulin.
Benzodiazepine.
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Binding to the presynaptic alpha 2 release modulating receptors

27. What are common serious side effects of Aminoglycosides and What are these associated with?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Inhibits DNA dependent RNA polymerase
bradycardia - AV block - CHF

28. Side effects of Isoniazid (INH)?
Pentavalent Antimony
anticholinesterase glaucoma
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

29. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
Those patients who are taking nitrates.
- Haloperidol - chlorpromazine - reserpine - MPTP
Cardiac glycoside (inotropic agent).
Prevents the release of Ca from SR of skeletal muscle

30. Digoxin v. Digitoxin: protein binding?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Digitoxin 70% Digoxin 20-40%
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

31. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
post MI and digitalis induced arrhythmias
Epinephirine(Alpha1 -2 and Beta 1 -2)

32. Cocaine shares is mechanism of action with What antidepressant
TCA
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
DHPG (dihydroxy-2- propoxymethyl guanine)
Neutropenia

33. List the specific antidote for this toxin: Antimuscarinic (anticholinergic)
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
cholestyramine - colestipol
prevention of nodal arrhythmias (SVT)
- Physostigmine salicylate

34. What are the clinical uses for 3rd Generation Cephalosporins?
cyanide toxicity (releases CN)
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

35. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
decrease conduction velocity - increase ERP - increase PR interval
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Pseudomonas species and Gram - rods
Same as penicillin. Extended spectrum antibiotics

36. What is the MOA for Clindamycin?
very short acting
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Used in combination therapy with SMZ to sequentially block folate synthesis

37. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
INH: Injures Neurons and Hepatocytes
As an anticholinesterase it increases endogenous ACh and thus increases strength.
- Physostigmine salicylate
Due to the presence of a bulkier R group

38. Can Heparin be used during pregnancy?
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Oxygen
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Yes - it does not cross the placenta.

39. Name three ACE inhibitors?
reversible SLE- like syndrome
torsade de pointes - excessive Beta block
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Captopril - Enalapril - Lisinopril

40. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
GI side effects. (Indomethacin is less toxic - more commonly used.)
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Antileukotriene; blocks synthesis by lipoxygenase.
Na/K ATPase

41. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
- Bleomycin - amiodarone - busulfan
Amphetamine and Ephedrine
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.

42. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
Babiturate.
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Diuresis in pateints with sulfa allergy
Choline acetyltransferase

43. What are four Sulfonylureas?
Reversible block of histamine H2 receptors
Pretreat with antihistamines and a slow infusion rate
TMP- SMZ (DOC) - aerosolized pentamidine
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

44. What is the category of drug names ending in - cillin (e.g. Methicillin)
Penicillin.
Benzathine penicillin G
Beta - lactamase cleavage of Beta - lactam ring
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness

45. Are Ampicillin and Amoxicillin are not...
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
With supplemental Folic Acid
penicillinase resistant
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules

46. What is the category of drug names ending in - tropin (e.g. Somatotropin)
Pituitary hormone.
- N- acetylcystine
Acute gout.
Digitoxin 168hrs Digoxin 40 hrs

47. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Yes
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
- Antipsychotics

48. Beta Blockers - BP?
decrease
Hypersensitivity reactions
physostigmine
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

49. How is Griseofulvin used clinically?
Oral treatment of superficial infections
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Nifedipine - Verapamil - Diltiazem
Impairs the synthesis of vitamin K- dependent clotting factors

50. Resistance mechanisms for Macrolides

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