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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 are the HIV drugs used clinically?

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2. What is a mnemonic to remember Amantadine's function?
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Penicillin.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Blocks Influenza A and RubellA; causes problems with the cerebellA

3. What is the mechanism of action of the Alpha - glucosidase inhibitors?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
aPTT (intrinsic pathway)
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
block Na+ channels in the cortical collecting tubule

4. What class of drug is echothiophate? What is its indication?
check PFTs - LFTs - and TFTs
anticholinesterase glaucoma
Penicillin.
Aplastic anemia (dose independent) - Gray Baby Syndrome

5. K+ sparing diuretics - site of action?
Those patients who are taking nitrates.
cortical collecting tubule
Short.
Cell membrane Ca2+ channels of cardiac sarcomere

6. What is the mechanism of action of the thrombolytics?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
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.)

7. What is the possible mechanism and effect of Metformin in treating diabetes?
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
Sildenafil fills the penis

8. Acetazolamide - clinical uses?
GI side effects. (Indomethacin is less toxic - more commonly used.)
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Acts as a wide spectrum carbapenem

9. What is the mechanism of action of Colchicine used to treat acute gout?
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Benzodiazepine.
Does not cross

10. What are Aminoglycosides synergistic with?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
troponin - tropomyosin system
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.
Beta - lactam antibiotics

11. List the mechanism - clinical use - & toxicity of 5 FU.
RESPIre
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Gram + and Anerobes

12. Which drug(s) cause this reaction: Aplastic anemia (5)?
- Alkalate DNA - Brain tumors - CNS toxicity
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Tricyclic antidepressant.
BM suppression (neutropenia - anemia) - Peripheral neuropathy

13. Which RT inhibitors cause a Rash?
Non - Nucleosides
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
- Dimercaprol - succimer

14. What is the clinical use for Ampicillin and Amoxicillin?
Acute (hours)
Decreases synthesis of Mycolic Acid
viral kinase
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods

15. How is Foscarnet used clinically?
check PFTs - LFTs - and TFTs
- Shifts the curve to the right - increases Km
Amphotericin B - Nystatin - Fluconazole/azoles
CMV Retinitis in IC pts When Ganciclovir fails

16. List the specific antidote for this toxin: Amphetamine
TMP- SMZ
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
- Ammonium Chloride
Intrathecally

17. Beta Blockers - CV toxicity?
bradycardia - AV block - CHF
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Carbachol - pilocarpine - physostigmine - echothiophate
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

18. How is Acyclovir used clinically?
very short acting
It must be Phosphorylated by Viral Thymidine Kinase
Epinephrine
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

19. Explain potency in relation to full and partial agonists(2).
1. Antiandrogen 2. Nausea 3. Vomiting
- aminoglycosides - loop diuretics - cisplatin
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
AluMINIMUM amount of feces.

20. How is Amphotericin B administered for fungal meningitis?
Digoxin=urinary Digitoxin=biliary
Same as penicillin. Act as narrow spectrum antibiotics
Rifampin
Intrathecally

21. Acetazolamide - mechanism?
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Staphlococcus aureus
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

22. Which cancer drugs work at the level of mRNA(2)?
- Steroids - Tamoxifen
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)

23. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
Impairs the synthesis of vitamin K- dependent clotting factors
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
- Cloazapine - carbamazapine - colchicine - PTU
- Ethosuxamide - sulfonamides - lamotrigine

24. List the specific antidote for this toxin: Warfarin
- Vitamin K & fresh frozen plasma
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Penicillin.
1. Acarbose 2. Miglitol

25. What is the MOA of Amantadine?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
aPTT (intrinsic pathway)
cyanide toxicity (releases CN)

26. Cocaine shares is mechanism of action with What antidepressant
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
dizziness - flushing - constipation (verapamil) - nausea
TCA

27. What are two toxicities of the Sulfonylureas?
TMP- SMZ (DOC) - aerosolized pentamidine
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Binding to the presynaptic alpha 2 release modulating receptors
Diarrhea

28. What are the side effects of Polymyxins?
Yes
Pralidoxime regenerates active cholinesterase.
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Neurotoxicity - Acute renal tubular necrosis

29. Which drug(s) cause this reaction: P450 inhibition(6)?
cortical collecting tubule
Oral
- Flumazenil
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

30. Which drug increases Sys BP w/o affecting Pulse Pressure
Decreased uptake or Increased transport out of cell
1. Antiandrogen 2. Nausea 3. Vomiting
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Epinephrine

31. Acetazolamide causes?

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32. K+ sparing diuretics - toxicity?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Hydralazine and Minoxidil
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate

33. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Ataxia - Dizziness - Slurred speech

34. What is a common drug interaction associated with Griseofulvin?
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- Tetracycline
Increases coumadin metabolism
Antileukotriene; blocks synthesis by lipoxygenase.

35. MOA: Disrupt bacterial/fungal cell membranes
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Topical and Oral - for Oral Candidiasis (Thrush)
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Polymyxins

36. What is the definition of zero - order kinetics? Example?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

37. List the mechanism - clinical use - & toxicity of Etoposide.
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Binds ergosterol - Disrupts fungal membranes
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

38. Adverse effects of Guanethidine?
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- Penicillamine
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Albuterol - tertbutaline

39. How does Ganciclovir's toxicity relate to that of Acyclovir?
Ganciclovir is more toxic to host enzymes
loop diuretics - spironolactone
Pituitary hormone.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)

40. What is the category of drug names ending in - olol (e.g. Propranolol)
Beta antagonist.
TMP- SMZ
Slow - limited by half lives of clotting factors
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

41. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
effective in torsade de pointes and digoxin toxicity
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Lidocaine - Mexiletine - Tocainide
Babiturate.

42. What are five toxicities associated with Tacrolimus (FK506)?
Peptic ulcer disease.
Competitive inibitor of progestins at progesterone receptors.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

43. How does angiotensin II affect NE release?
Binds to the Pyrophosphate Binding Site of the enzyme
It acts presynaptically to increase NE release.
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

44. Name some common Tetracyclines (4)
Inhibit Ergosterol synthesis
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Tetracycline - Doxycycline - Demeclocycline - Minocycline
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

45. What organisms does Griseofulvin target?
Dermatophytes (tinea - ringworm)
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
decrease

46. What is the major side effect for Ampicillin and Amoxicillin?
Hypersensitivity reactions
Antibiotic - protein synthesis inhibitor.
RESPIre
amphetamine and ephedrine

47. What is the mechanism of action of Sildenafil (Viagra)?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
bradycardia - AV block - CHF

48. What side effect of using atropine to induce pupillary dilation would you expect?
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
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).

49. ___________ are Teratogenic
- Vinca alkaloids(inhibit MT) - Paclitaxel
Aminoglycosides
Aplastic anemia (dose independent) - Gray Baby Syndrome
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

50. Name three Antiarrhythmic drugs in class IB.
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Lidocaine - Mexiletine - Tocainide
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.