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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. How do you treat coma in the ER (4)?
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
thick ascending limb
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

2. Adverse effects of Captopril?
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
- Act on same receptor - Full has greater efficacy
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

3. What is the MOA of Ribavirin?
It affects beta receptors equally and is used in AV heart block (rare).
prevention of nodal arrhythmias (SVT)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
- Alkalate DNA - Brain tumors - CNS toxicity

4. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
competitive inhibirot of aldosterone in the cortical collecting tubule
scopolamine
TCA
Treatment of infertility.

5. What is an occasional side effect of Aztreonam?
GI upset
Hypersensitivity reactions
1. Antiandrogen 2. Nausea 3. Vomiting
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

6. What are the products and their toxicities of the metabolism of Methanol by / alcohol dehydrogenase?
- Formaldehyde & formic acid - severe acidosis & retinal damage
- Methylene blue
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

7. ________ ae not resistant to penicillinase - - but they are less susceptible than the other Beta lactams
Beta Blockers
Cephalosporins
Bacitracin - Vancomycin
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

8. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Mebendazole/Thiabendazole - Pyrantel Pamoate
Those patients who are taking nitrates.
Cyclooxygenases (COX I - COX II).
Cilastatin

9. Ethacrynic Acid - mechanism?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Chronic Hepatitis A and B - Kaposi's Sarcoma
Carbenicillin - Piperacillin - and Ticarcillin
not a sulfonamide - but action is the same as furosemide

10. Antimicrobial prophylaxis for a history of recurrent UTIs
TMP- SMZ
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

11. Hydrochlorothiazide - mechanism?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Same as penicillin. Act as narrow spectrum antibiotics

12. What is the category of drug names ending in - tropin (e.g. Somatotropin)
Pituitary hormone.
CMV Retinitis in IC pts When Ganciclovir fails
Potent immunosuppressive used in organ transplant recipients.
Bleeding.

13. What enzyme does Zileuton inhibit?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Lipoxygenase
BM suppression (neutropenia - anemia) - Peripheral neuropathy

14. What are three possible toxicities of NSAID usage?
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Dermatophytes (tinea - ringworm)
1. Renal damage 2. Aplastic anemia 3. GI distress

15. Antiarrhythmic class IB- effects?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Rapid (seconds)

16. Resistance mechanisms for Aminoglycosides
Dopamine; causes its release from intact nerve terminals
is resistant
Liver
Modification via Acetylation - Adenylation - or Phosphorylation

17. When is HIV therapy initiated?
Blood
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

18. What is the mecanism of action of Sucralfate?
Inhibits CMV DNA polymerase
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.
H2 antagonist
Erythromycin - Azithromycin - Clarithromycin

19. Antimicrobial prophylaxis for Syphilis
- Alkalinize urine & dialysis
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Slow - limited by half lives of clotting factors
Benzathine penicillin G

20. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
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.
Praziquantel

21. What is the main clinical use for the thrombolytics?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Pyridoxine (B6) administration
severe hypertension - CHF
Early myocardial infarction.

22. Guanethidine enhances the release of Norepi?
- Deferoxamine
No - it inhibits the release of Nor Epi
- Lithium
Nevirapine - Delavirdine

23. What is the clinical use for Sildenafil (Viagra)?
Erectile dysfunction.
BM suppression (neutropenia - anemia) - Peripheral neuropathy
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
scopolamine

24. Ca2+ channel blockers - toxicity?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Intrathecally
cardiac depression - peripheral edema - flushing - dizziness - constipation
Binds ergosterol - Disrupts fungal membranes

25. What microorganisms is Aztreonam not effective against?
Gram + and Anerobes
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Blood
Acts as a wide spectrum carbapenem

26. What is the mechanism of action of the H2 Blockers?
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
severe hypertension - CHF
Reversible block of histamine H2 receptors
Heparin catalyzes the activation of antithrombin III.

27. Furosemide increases the excretion of What ion?
Non - Nucleosides
Ca2+ (Loops Lose calcium)
- EDTA - dimercaprol - succimer - & penicillamine
Mebendazole/Thiabendazole - Pyrantel Pamoate

28. What is an acronym to remember Anti - TB drugs?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
With an amino acid change of D- ala D- ala to D- ala D- lac
- ACE inhibitors (Losartan>no cough)
RESPIre

29. What are three possible complications of Heparin therapy?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
proximal convoluted tubule - thin descending limb - and collecting duct
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

30. How can the t1/2 of INH be altered?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Nucleosides
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Fast vs. Slow Acetylators

31. Why is pyridostigmine effective in the treatment of myasthenia gravis?
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Tetracycline - Doxycycline - Demeclocycline - Minocycline

32. List the specific antidote for this toxin: Cyanide
Does not cross
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
- Nitrate - hydroxocobalamin thiosulfate
Primaquine

33. K+- clinical use?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
depresses ectopic pacemakers - especially in digoxin toxicity
Pituitary hormone.
Ceftriaxone

34. What is Nifurtimox administered for?

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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).
Ipratropium
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

36. Name five Antiarrhythmic drugs in class II?
propanolol - esmolol - metoprolol - atenolol - timolol
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
H2 antagonist

37. What is the lab value used to monitor the effectiveness of Warfarin therapy?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
The PT.
Prevents the release of Ca from SR of skeletal muscle
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

38. What type of gout is treated with Colchicine?
Indomethacin is used to close a patent ductus arteriosus.
Digitoxin 70% Digoxin 20-40%
Acute gout.
Blood

39. How does resistance to Vancomycin occur?
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Beta - lactam antibiotics
With an amino acid change of D- ala D- ala to D- ala D- lac
Small lipid - soluble molecule

40. Acetazolamide - mechanism?
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.
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
- Tamoxifen

41. Steady state concentration is reached in __ number of half - lifes
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- NaHCO3

42. What type of gout is treated with Probenacid?
Chronic gout.
TMP- SMZ (DOC) - aerosolized pentamidine
Premature infants - because they lack UDP- glucuronyl transferase
Pseudomembranous colitis (C. difficile) - fever - diarrhea

43. Why would you give a drug like pancuronium or succinylcholine?
Pituitary hormone.
Rifampin (DOC) - minocycline
Useful in muscle paralysis during surgery or mechanical ventilation.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

44. What is the MOA for Trimethoprim (TMP)?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
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.
Sulfonamides - Trimethoprim

45. How is Chloramphenical used clinically?
- NaHCO3
Pentavalent Antimony
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Rifampin (DOC) - minocycline

46. MOA: Block protein synthesis at 50s subunit
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
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.

47. What drug is given for Pneumocystis carinii prophylaxis?
prevention of nodal arrhythmias (SVT)
Pentamidine
- Tetracycline - amiodarone - sulfonamides
Modification via Acetylation - Adenylation - or Phosphorylation

48. What are common toxic side effects of Sulfonamides? (5)
Scopolamine
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

49. What are three complications of Warfarin usage?
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
carbonic anhydrase inhibitors - K+ sparing diuretics

50. Acetazolamide - clinical uses?
Abortifacient.
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
anticholinesterase glaucoma
Pseudomembranous colitis (C. difficile) - fever - diarrhea