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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. MOA: Block DNA topoisomerases
first dose orthostatic hypotension - dizziness - headache
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Large anionic polymer - acidic
Quinolones

2. Name three ACE inhibitors?
Beta -2 agonist.
Blood
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Captopril - Enalapril - Lisinopril

3. Isopoterenol was given to a patient with a developing AV block - why?
- Glucocorticoid withdrawal
Pyridoxine (B6) administration
Stimulates beta adrenergic receptors
orthostatic and exercise hypotension - sexual dysfunction - diarrhea

4. List some specifics of lead poisoning(4)?
Triple sulfas or SMZ
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
GI discomfort
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

5. Toxicities associated with Acyclovir?
Delirium - Tremor - Nephrotoxicity
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Rare.
- Tricyclic antidepressants

6. Hydralazine - clinical use?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
torsade de pointes - excessive Beta block
severe hypertension - CHF
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

7. What is a common drug interaction associated with Griseofulvin?
Increases coumadin metabolism
It affects beta receptors equally and is used in AV heart block (rare).
1. Antiandrogen 2. Nausea 3. Vomiting
Methicillin - Nafcillin - and Dicloxacillin

8. What is the clinical use of Tacrolimus (FK506)?
Potent immunosuppressive used in organ transplant recipients.
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
CL= (rate of elimination of drug/ Plasma drug conc.)

9. What is the effect of guanethidine on adrenergic NE release?
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
Minor hepatotoxicity - Drug interactions (activates P450)
It inhibits release of NE.
- Lithium

10. Acetazolamide - mechanism?
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
NO
hyperaldosteronism - K+ depletion - CHF
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

11. List the specific antidote for this toxin: Acetaminophen
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
It affects beta receptors equally and is used in AV heart block (rare).
The PTT.
- N- acetylcystine

12. List the mechanism - clinical use - & toxicity of 6 MP.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Ipratropium
- N- acetylcystine

13. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
hypertension - angina - arrhythmias
DHPG (dihydroxy-2- propoxymethyl guanine)
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

14. Which drug(s) cause this reaction: Adrenocortical Insufficiency
- Glucocorticoid withdrawal
CL= (rate of elimination of drug/ Plasma drug conc.)
- Penicillin
Choline acetyltransferase

15. Which diuretics cause alkalosis?
loop diuretics - thiazides
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Increases coumadin metabolism
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

16. When is Rifampin not used in combination with other drugs?
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Pyridoxine (B6) administration
Amphetamine and Ephedrine
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B

17. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
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.
Inhibits DNA dependent RNA polymerase
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

18. What is the mechanism of action of NSAIDs other than Aspirin?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Heparin catalyzes the activation of antithrombin III.
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Beta - lactam antibiotics

19. ________ ae not resistant to penicillinase - - but they are less susceptible than the other Beta lactams
- Tricyclic antidepressants
Cephalosporins
Praziquantel
Modification via Acetylation

20. List five common glucocorticoids.
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Chronic gout.

21. Adverse effects of beta - blockers?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Flecainide - Encainide - Propafenone

22. Beta Blockers - CV toxicity?
bradycardia - AV block - CHF
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Sotalol - Ibutilide - Bretylium - Amiodarone
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise

23. Adverse effects of Losartan?
fetal renal toxicity - hyperkalemia
Give an antichloinesterase - neostigmine - edrophonium - etc
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Anaerobes

24. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
Rare.
Aminoglycosides
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Erythromycin - Azithromycin - Clarithromycin

25. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Digoxin=urinary Digitoxin=biliary
It acts presynaptically to increase NE release.
Ibuprofen - Naproxen - and Indomethacin
Epinephirine(Alpha1 -2 and Beta 1 -2)

26. Decrease Digoxin dose in renal failure?
No - warfarin - unlike heparin - can cross the placenta.
YES
Neomycin
AluMINIMUM amount of feces.

27. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
- Ethosuxamide - sulfonamides - lamotrigine
Carbenicillin - Piperacillin - and Ticarcillin
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
INH: Injures Neurons and Hepatocytes

28. Which diuretics decrease urine Ca2+?
thiazides - amiloride
Methicillin - Nafcillin - and Dicloxacillin
fetal renal toxicity - hyperkalemia
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

29. Which Tetracycline is used in patients with renal failure? / Why?
Choline acetyltransferase
Doxycycline - because it is fecally eliminated
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
- Steroids - Tamoxifen

30. What is the category of drug names ending in - pril (e.g. Captopril)
- Cloazapine - carbamazapine - colchicine - PTU
ACE inhibitor.
Diarrhea
Saquinavir - Ritonavir - Indinavir - Nelfinavir

31. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Mebendazole/Thiabendazole - Pyrantel Pamoate
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Pseudomonas species and Gram - rods

32. How do spare receptors effect the Km?
aPTT (intrinsic pathway)
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
- ED 50 is less than the Km (less than 50% of receptors)
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

33. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Cephalosporins
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil

34. What is a possible toxicity of Ticlopidine - Clopidogrel usage?
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
fetal renal toxicity - hyperkalemia
Albuterol - tertbutaline
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

35. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Rifampin (DOC) - minocycline
Penicillin.
Norepinephrine
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

36. Digoxin v. Digitoxin: half life?
Triple sulfas or SMZ
Because they require some residual islet function.
Digitoxin 168hrs Digoxin 40 hrs
- Deferoxamine

37. What are five toxicities associated with Tacrolimus (FK506)?
Severe Gram - rod infections.
viral kinase
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

38. What is the mechanism of action of the Sulfonylureas?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Tricyclic antidepressant.
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

39. What are two Alpha - glucosidase inhibitors?
1. Acarbose 2. Miglitol
AZT
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Decreases synthesis of Mycolic Acid

40. How can the t1/2 of INH be altered?
The PTT.
Yes
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Fast vs. Slow Acetylators

41. How do the Protease Inhibitors work?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
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.
Inhibt Assembly of new virus by Blocking Protease Enzyme
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

42. Name three Antiarrhythmic drugs in class IC.
competitive inhibirot of aldosterone in the cortical collecting tubule
Flecainide - Encainide - Propafenone
Oral
new arrhythmias - hypotension

43. What is the clinical use for Nystatin?
Topical and Oral - for Oral Candidiasis (Thrush)
Beta adrenergic receptors and Ca2+ channels (stimulatory)
- Dimercaprol - succimer
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

44. Name the steps in drug approval(4)?
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
As an anticholinesterase it increases endogenous ACh and thus increases strength.
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
It inhibits release of NE.

45. If a patient is given hexamethonium - What would happen to his/her heart rate?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
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.
Beta - lactam antibiotics
Yes

46. What is Metronidazole combined with for 'triple therapy'? Against What organism?
- Nitrate - hydroxocobalamin thiosulfate
Protease Inhibitors and Reverse Transcriptase Inhibitors
- Oral Contraceptives
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

47. Are not penicillinase resistant
Disulfiram - like reaction with EtOH - Headache
block Na+ channels in the cortical collecting tubule
Carbenicillin - Piperacillin - and Ticarcillin
Inhibits reabsorption of uric acid.

48. Name the common Azoles
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)
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Pituitary hormone.

49. How are the HIV drugs used clinically?

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50. What drug is used to diagnose myasthenia gravis?
Long.
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
edrophonium (extremely short acting anticholinesterase)
Beta1 more than B2