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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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1. Adverse effects of Nifedipine - verapamil?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Due to the presence of a bulkier R group
Bleeding.
dizziness - flushing - constipation (verapamil) - nausea

2. What is the mechanism of Leuprolide?
Binds to the Pyrophosphate Binding Site of the enzyme
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
hypertension - CHF - diabetic renal disease
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

3. What is the clinical use of Mifepristone (RU486)?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Abortifacient.
sedation - sleep alterations
Inhibit viral DNA polymerase

4. Procainamide - toxicity?
Verapamil - Diltiazem - Bepridil
Inhibits CMV DNA polymerase
reversible SLE- like syndrome
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

5. Name three K+ sparing diuretics?
Spironolactone - Triamterene - Amiloride (the K+ STAys)
- Methylene blue
Amphotericin B - Nystatin - Fluconazole/azoles
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH

6. Do Tetracyclines penetrate the CNS?
Only in limited amounts
Beta antagonist.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
- Disulfram & also sulfonylureas - metronidazole

7. What is the mechanism of action of Acetaminophen?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
propanolol - esmolol - metoprolol - atenolol - timolol
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

8. List the specific antidote for this toxin: Amphetamine
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Clavulanic acid
- Ammonium Chloride
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas

9. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
AZT - to reduce risk of Fetal Transmission

10. What drug is used to diagnose myasthenia gravis?
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
edrophonium (extremely short acting anticholinesterase)
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Yes

11. What is the only depolarizing neuromuscular blocking agent?
Ceftriaxone
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Succinylcholine
Blocks Norepi - but not Dopamine

12. IV Penicillin
Nevirapine - Delavirdine
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Botulinum
Penicillin - G

13. What is the receptor affinity and clinical use of isoproterenol?
It affects beta receptors equally and is used in AV heart block (rare).
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)

14. What is the effect of TCA's on the adrenergic nerve?
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

15. What are two toxicities of the Sulfonylureas?
Beta Blockers
CL= (rate of elimination of drug/ Plasma drug conc.)
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
AZT

16. What is the major toxic side effect of Penicillin?
Ca2+ (Loops Lose calcium)
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
G6PD deficient individuals
Hypersensitivity reactions

17. List five common glucocorticoids.
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Prevents the release of Ca from SR of skeletal muscle
- Cloazapine - carbamazapine - colchicine - PTU
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

18. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
With supplemental Folic Acid
Hydralazine and Minoxidil
No
- Quinidine - quinine

19. For Heparin What is the Treatment for overdose
- aminoglycosides - loop diuretics - cisplatin
Protamine sulfate
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
ACIDazolamide' causes acidosis

20. What is Imipenem always administered with?
Cyclooxygenases (COX I - COX II).
Interstitial nephritis
hyperaldosteronism - K+ depletion - CHF
Cilastatin

21. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
troponin - tropomyosin system
Increase target cell response to insulin.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

22. Explain potency in relation to full and partial agonists(2).
Rash - Pseudomembranous colitis
- Penicillamine
Succinylcholine
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

23. Are Ampicillin and Amoxicillin are not...
Inhibt Assembly of new virus by Blocking Protease Enzyme
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
penicillinase resistant
Ganciclovir is more toxic to host enzymes

24. Furosemide - class and mechanism?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
- Oral Contraceptives
local anesthetic. CNS stimulation or depression. CV depression.
loop diuretics - thiazides

25. Which individuals are predisposed to Sulfonamide - induced hemolysis?
- Shifts the curve to the right - increases Km
G6PD deficient individuals
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

26. List the mechanism - clinical use - & toxicity of Busulfan.
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Potent immunosuppressive used in organ transplant recipients.
ACIDazolamide' causes acidosis
- Alkalinize urine & dialysis

27. What physiological effects was the Anes using Atropine to tx
- Isoniazid
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
anuria - CHF

28. How does botulinum toxin result in respiratory arrest?
No - it inhibits the release of Nor Epi
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
- ACE inhibitors (Losartan>no cough)
Prevents the release of ACh - Which results in muscle paralysis.

29. What is the clinical use for Nystatin?
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Topical and Oral - for Oral Candidiasis (Thrush)
Bacitracin - Vancomycin

30. Which Tetracycline is used in patients with renal failure? / Why?
Doxycycline - because it is fecally eliminated
Tetracycline - Doxycycline - Demeclocycline - Minocycline
GI discomfort
Flecainide - Encainide - Propafenone

31. What is the mechanism of action of the Sulfonylureas?
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- Antipsychotics
- Ammonium Chloride
AV nodal cells

32. Beta Blockers - BP?
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
proximal convoluted tubule
decrease
As an anticholinesterase it increases endogenous ACh and thus increases strength.

33. List the specific antidote for this toxin: Carbon monoxide
thiazides - amiloride
- NaHCO3
-100% oxygen - hyperbaric
Forms toxic metabolites in the bacterial cell - Bactericidal

34. For Warfarin What is the Onset of action
With supplemental Folic Acid
Slow - limited by half lives of clotting factors
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
GI disturbances.

35. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
dry mouth - sedation - severe rebound hypertension
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

36. What process does Zafirlukast interfere with?
GET on the Metro
Leukotrienes increasing bronchial tone.
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Modification via Acetylation

37. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Atropine & pralidoxime
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

38. What type of patient should not take Misoprostol and why?
Blocks Norepi - but not Dopamine
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Flecainide - Encainide - Propafenone

39. Name three ACE inhibitors?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
CMV - esp in Immunocompromised patients
Captopril - Enalapril - Lisinopril
-100% oxygen - hyperbaric

40. Which drug(s) cause this reaction: Pseudomembranous colitis?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
- Clindamycin
cholestyramine - colestipol
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic

41. What is the category of drug names ending in - oxin (e.g. Digoxin)
Yes - it does not cross the placenta.
With an amino acid change of D- ala D- ala to D- ala D- lac
Cardiac glycoside (inotropic agent).
Potent immunosuppressive used in organ transplant recipients.

42. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
viral kinase
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Diarrhea

43. What are Polymyxins used for?
Resistant Gram - infections
Chronic anticoagulation.
With an amino acid change of D- ala D- ala to D- ala D- lac
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)

44. What are the products and their toxicities of the metabolism of Ethylene Glycol by / alcohol dehydrogenase?
Nitrates
- Oxalic acid - Acidosis & nephrotoxicity
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
These B-2 agonists cause respiratory smooth muscle to relax.

45. What are the clinical indications for Azole therapy?
dry mouth - sedation - severe rebound hypertension
Systemic mycoses
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Acetylcholinesterase; ACh is broken down into choline and acetate.

46. Name two LPL stimulators.
- Disulfram & also sulfonylureas - metronidazole
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Methylation of rRNA near Erythromycin's ribosome binding site
Gemfibrozil - Clofibrate

47. What is the MOA for the Azoles?
GI distress - Skin rash - and Seizures at high plasma levels
- Hydralazine - Procainamide - INH - phenytoin
Inhibit Ergosterol synthesis
TMP- SMZ

48. What are toxic side effects for Metronidazole?
- Antipsychotics
Nephrotoxicity
Inhalational general anesthetic.
Disulfiram - like reaction with EtOH - Headache

49. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Choline acetyltransferase

50. Which cancer drugs inhibit nucleotide synthesis(3)?
- Phenytoin
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Paranteral (IV - SC)
- Methotrexate - 5 FU - 6 mercaptopurine