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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 antimicrobial class is Aztreonam syngergestic with?
troponin - tropomyosin system
Aminoglycosides
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

2. How can the t1/2 of INH be altered?
Liver
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Fast vs. Slow Acetylators
ACIDazolamide' causes acidosis

3. What is the chemical name for Ganciclovir?
Used in combination therapy with SMZ to sequentially block folate synthesis
GET on the Metro
DHPG (dihydroxy-2- propoxymethyl guanine)
hypertension - CHF - diabetic renal disease

4. What is Metronidazole used for clinically?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Albuterol - tertbutaline
Same as penicillin. Act as narrow spectrum antibiotics
Sotalol - Ibutilide - Bretylium - Amiodarone

5. What is the main clinical use for the thrombolytics?
Early myocardial infarction.
Vd= (Amt. of drug in body/ Plasma drug conc.)
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Chronic Hepatitis A and B - Kaposi's Sarcoma

6. What beta 2 agonist will help your 21yo Astma pt?
Constant FRACTION eliminated per unit time.(exponential)
scopolamine
post MI and digitalis induced arrhythmias
Albuterol - tertbutaline

7. Which diuretics increase urine Ca2+?
ACE inhibitor.
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Beta antagonist.
loop diuretics - spironolactone

8. Classes of antihypertensive drugs?
- Physostigmine salicylate
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Hydralazine and Minoxidil
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

9. What are common side effects of Amphotericin B?
Beta1 more than B2
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Liver
Nevirapine - Delavirdine

10. Ca2+ channel blockers - toxicity?
Tricyclic antidepressant.
sedation - depression - nasal stuffiness - diarrhea
cardiac depression - peripheral edema - flushing - dizziness - constipation
Same as penicillin. Act as narrow spectrum antibiotics

11. Which drug(s) cause this reaction: Tardive dyskinesia?
- Antipsychotics
Chronic gout.
- Oxalic acid - Acidosis & nephrotoxicity
Succinylcholine

12. What are four conditions in Which H2 Blockers are used clinically?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
- Lithium
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions

13. Why is there a drop in systolic - mean - and diastolic bp with infusion of isoproterenol?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas

14. List the specific antidote for this toxin: Arsenic (all heavy metals)
Stimulates beta adrenergic receptors
- Dimercaprol - succimer
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Paranteral (IV - SC)

15. Nifedipine has similar action to?
Delirium - Tremor - Nephrotoxicity
Nitrates
Aminoglycosides
- Steroids - Tamoxifen

16. Steady state concentration is reached in __ number of half - lifes
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Cardiac glycoside (inotropic agent).

17. Antimicrobial prophylaxis for PCP
Digitoxin 168hrs Digoxin 40 hrs
TMP- SMZ (DOC) - aerosolized pentamidine
- Glucagon
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.

18. Why are albuterol and terbutaline effective in tx of acute asthmatic attacks?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
These B-2 agonists cause respiratory smooth muscle to relax.
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Spironolactone - Triamterene - Amiloride (the K+ STAys)

19. Foscarnet does not require activation by a...
Hydralazine and Minoxidil
viral kinase
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Butyrophenone (neuroleptic).

20. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Tricyclic antidepressant.
Impairs the synthesis of vitamin K- dependent clotting factors
Delirium - Tremor - Nephrotoxicity
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

21. How would you treat African Trypanosomiasis (sleeping sickness)?
- Disulfram & also sulfonylureas - metronidazole
- Shifts the curve to the right - increases Km
Suramin
Erythromycin - Azithromycin - Clarithromycin

22. What microorganisms are Aminoglycosides ineffective against?
Anaerobes
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Heparin catalyzes the activation of antithrombin III.

23. What are the clinical indications for bethanechol?
GI side effects. (Indomethacin is less toxic - more commonly used.)
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
YES
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.

24. Sotalol - toxicity?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
prevention of nodal arrhythmias (SVT)
torsade de pointes - excessive Beta block
- Tetracycline

25. 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
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.

26. What are three toxicities of Leuprolied?
Pseudomonas species and Gram - rods
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
Pseudomembranous colitis (C. difficile) - fever - diarrhea
1. Antiandrogen 2. Nausea 3. Vomiting

27. How does botulinum toxin result in respiratory arrest?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
hyperaldosteronism - K+ depletion - CHF
Prevents the release of ACh - Which results in muscle paralysis.

28. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
Fast vs. Slow Acetylators
Protease inhibitor.
Quinolones
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

29. Which RT inhibitors cause a Rash?
Non - Nucleosides
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
- B51Naloxone / naltrexone (Narcan)

30. What are toxicities associated with Chloramphenicol?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Pregnant women - Children; because animal studies show Damage to Cartilage
Aplastic anemia (dose independent) - Gray Baby Syndrome
depresses ectopic pacemakers - especially in digoxin toxicity

31. What is the MOA for the Aminoglycosides?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
post MI and digitalis induced arrhythmias
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.

32. IV Penicillin
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Inhibits DNA dependent RNA polymerase
for RSV
Penicillin - G

33. How is Rifampin used clinically?
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
- NaHCO3
new arrhythmias - hypotension
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

34. Which drug(s) cause this reaction: Diabetes insipidus?
- Lithium
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)

35. What are the clinical uses for 3rd Generation Cephalosporins?
Enterobacter
Blocks Norepi - but not Dopamine
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
They inhibit reuptake of NE at the nerve terminal (as does cocaine).

36. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
Scopolamine
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Rheumatoid and osteoarthritis.
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)

37. What are are the Sulfonylureas (general description) and What is their use?
Diarrhea
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes

38. Why does NE result in bradycardia?
amphetamine and ephedrine
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Chronic (weeks or months)
Impairs the synthesis of vitamin K- dependent clotting factors

39. Procainamide - toxicity?
Oral
reversible SLE- like syndrome
hypertension - CHF - diabetic renal disease
- Disulfram & also sulfonylureas - metronidazole

40. List the specific antidote for this toxin: Anticholinesterases (organophosphate.)
- Atropine & pralidoxime
Rash - Pseudomembranous colitis
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

41. Bretyllium - toxicity?
Aminoglycosides - Tetracyclines
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
new arrhythmias - hypotension

42. Common toxicities associated with Griseofulvin?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Teratogenic - Carcinogenic - Confusion - Headaches

43. What is the MOA of the RT Inhibitors?
YES
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
amphetamine and ephedrine

44. What is the MOA of Aztreonam?
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Binds to the Pyrophosphate Binding Site of the enzyme
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Diuresis in pateints with sulfa allergy

45. What is the mecanism of action of Sucralfate?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Pentavalent Antimony
Interstitial nephritis
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.

46. What is an occasional side effect of Aztreonam?
- Aminocaproic acid
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Inhibit Ergosterol synthesis
GI upset

47. What are the clinical uses for Aztreonam?
Heparin catalyzes the activation of antithrombin III.
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
physostigmine

48. What is Clindamycin used for clinically?
Because they require some residual islet function.
post MI and digitalis induced arrhythmias
Enterobacter
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

49. What enzyme does Zileuton inhibit?
Lipoxygenase
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Antileukotriene; blocks synthesis by lipoxygenase.
Digitoxin 168hrs Digoxin 40 hrs

50. Describe the MOA of Interferons (INF)
Digitoxin 70% Digoxin 20-40%
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Protease Inhibitors and Reverse Transcriptase Inhibitors
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis