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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 beta 2 agonist will help your 21yo Astma pt?
Albuterol - tertbutaline
Aminoglycosides - Tetracyclines
reversible SLE- like syndrome
hypertension - CHF - diabetic renal disease

2. What is the memory key for the effect of aluminum hydroxide overuse?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
AluMINIMUM amount of feces.
-100% oxygen - hyperbaric
As an anticholinesterase it increases endogenous ACh and thus increases strength.

3. Decrease Digoxin dose in renal failure?
Systemic mycoses
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
YES
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

4. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Rifampin (DOC) - minocycline

5. Explain potency in relation to full and partial agonists(2).
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
1. Weight gain 2. Hepatotoxicity (troglitazone)
CL= (rate of elimination of drug/ Plasma drug conc.)
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

6. Amiodarone - toxicity?
Yes - it does not cross the placenta.
loop diuretics - spironolactone
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
- polymyxins

7. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Acetylcholinesterase; ACh is broken down into choline and acetate.
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Cephalosporins

8. What is the mechanism of action of the thrombolytics?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Phosphorylation by a Viral Kinase
block Na+ channels in the cortical collecting tubule
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.)

9. What is an additional side effect of Methicillin?
Decreased uptake or Increased transport out of cell
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Treatment of infertility.
Interstitial nephritis

10. What are the indications for using amphetamine?

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11. Beta Blockers - CV toxicity?
bradycardia - AV block - CHF
Cardiac glycoside (inotropic agent).
Erythromycin - Azithromycin - Clarithromycin
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)

12. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
Topical and Oral - for Oral Candidiasis (Thrush)
Nephrotoxicity
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Rare.

13. Ca2+ channel blockers - clinical use?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
hypertension - angina - arrhythmias
- Steroids - Tamoxifen
Tendonitis and Tendon rupture

14. What is a common drug interaction associated with Griseofulvin?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
- Disulfram & also sulfonylureas - metronidazole
Competitive inibitor of progestins at progesterone receptors.
Increases coumadin metabolism

15. Why are the Sulfonylureas inactive in IDDM (type -1)?
very short acting
Slow - limited by half lives of clotting factors
Because they require some residual islet function.
As an anticholinesterase it increases endogenous ACh and thus increases strength.

16. How does a noncompetitive antagonist effect an agonist?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
- Act on same receptor - Full has greater efficacy
- Shifts the curve down - reduces Vmax
Beta -2 agonist.

17. Name five Antiarrhythmic drugs in class II?
Pyridoxine (B6) administration
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
propanolol - esmolol - metoprolol - atenolol - timolol
Nucleosides

18. What is the mechanism of Leuprolide?
depresses ectopic pacemakers - especially in digoxin toxicity
GnRH analog with agonist properties When used in pulsatile fashion and antagonist properties When used in continuous fashion - causing a transient initial burst of LH and FSH
ACIDazolamide' causes acidosis
Protamine sulfate

19. What are two toxicities associated with Cyclosporine?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Antifungal.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
AluMINIMUM amount of feces.

20. Which drug(s) cause this reaction: Cutaneous flushing (4)?
Pregnant women - Children; because animal studies show Damage to Cartilage
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
- Niacin - Ca++ channel blockers - adenosine - vancomycin

21. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

22. Which drug(s) cause this reaction: Disulfram - like reaction (4) ?
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
The only local anesthetic with vasoconstrictive properties.
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

23. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
- Phenytoin
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Phosphorylation by a Viral Kinase

24. What are four unwanted effects of Clomiphene use?
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Antileukotriene; blocks leukotriene receptors.
Beta1 more than B2

25. Digoxin v. Digitoxin: excretion?
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
- Glucocorticoid withdrawal
Gemfibrozil - Clofibrate
Digoxin=urinary Digitoxin=biliary

26. What is the MOA for Nystatin?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Pseudomonas species and Gram - rods
Binds ergosterol - Disrupts fungal membranes
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

27. How does botulinum toxin result in respiratory arrest?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Inhalational general anesthetic.
Prevents the release of ACh - Which results in muscle paralysis.
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

28. What are toxicities associated with Chloramphenicol?
IV vitamin K and fresh frozen plasma
Nucleosides
Aplastic anemia (dose independent) - Gray Baby Syndrome
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.

29. What are the clinical uses for Ticlopidine - Clopidogrel?
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Tetracycline - Doxycycline - Demeclocycline - Minocycline
The PT.
Diuresis in pateints with sulfa allergy

30. What are common toxicities associated with Tetracyclines?

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31. Which drug(s) cause this reaction: Atropine - like side effects?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
- Tricyclic antidepressants
Ibuprofen - Naproxen - and Indomethacin
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

32. K+ sparing diuretics - site of action?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
- Alkalinize urine & dialysis
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
cortical collecting tubule

33. What are five toxicities associated with Tacrolimus (FK506)?
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Beta1 more than B2
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

34. What are two processes Corticosteroids inhibit leading to decreased inflammation?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
- Chloramphenicol
TMP- SMZ (DOC) - aerosolized pentamidine
Protease Inhibitors and Reverse Transcriptase Inhibitors

35. Furosemide - toxicity? (OH DANG)
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Prophylaxis for Influenza A - Rubella; Parkinson's disease

36. Why does NE result in bradycardia?
It inhibits release of NE.
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

37. What is the category - method of use - and adverse effects of Salmeterol in Asthma treatment?
- Penicillamine
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Only in limited amounts

38. What is the mechanism of action of Allopurinol used to treat chronic gout?
Praziquantel
viral kinase
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

39. What is the memory key for the effect of magnesium hydroxide overuse?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Mg = Must go to the bathroom.

40. Adverse effect of Nitroprusside?
- Hydralazine - Procainamide - INH - phenytoin
With supplemental Folic Acid
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
cyanide toxicity (releases CN)

41. What is the category of drug names ending in - cillin (e.g. Methicillin)
Penicillin.
Prevents the release of ACh - Which results in muscle paralysis.
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Diarrhea

42. Ibutilide - toxicity?
Ca2+ (Loops Lose calcium)
Early myocardial infarction.
torsade de pointes
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

43. How is Amphotericin B used clinically?
Fast vs. Slow Acetylators
Gram + and Anerobes
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

44. What are two types of drugs that interfere with the action of Sucralfate and why?
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
pulmonary edema - dehydration

45. How is Vancomycin used clinically?
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Stimulates beta adrenergic receptors
For serious - Gram + multidrug - resistant organisms
Because they require some residual islet function.

46. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
Imipenem
Chronic gout.
Heparin catalyzes the activation of antithrombin III.
- Disulfram & also sulfonylureas - metronidazole

47. Ethacrynic Acid - toxicity?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
AZT
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Gram + and Anerobes

48. Sotalol - toxicity?
GI upset
torsade de pointes - excessive Beta block
CMV Retinitis in IC pts When Ganciclovir fails
Increases coumadin metabolism

49. Amprotericin B ___________ the BBB
Methylxanthine.
Pralidoxime regenerates active cholinesterase.
Digitoxin>95% Digoxin 75%
Does not cross

50. What are two indirect acting adrenergic agonists?
amphetamine and ephedrine
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Suramin
H2 antagonist