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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. MOA: Block DNA topoisomerases
Quinolones
Pregnant women - Children; because animal studies show Damage to Cartilage
- Alkalate DNA - Brain tumors - CNS toxicity
Intrathecally

2. How is Ganciclovir used clinically?
- polymyxins
CMV - esp in Immunocompromised patients
Triple sulfas or SMZ
Succinylcholine

3. What is Metronidazole combined with for 'triple therapy'? Against What organism?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Methylxanthine.
sedation - positive Coombs' test

4. Which RT inhibitor causes Megaloblastic Anemia?
AZT
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

5. Oral Penicillin
Penicillin - V
Butyrophenone (neuroleptic).
Methicillin - Nafcillin - and Dicloxacillin
Decreased uptake or Increased transport out of cell

6. How is Amphotericin B used clinically?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

7. How does NE modulate its own release? What other neurotransmitter has this same effect?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
fetal renal toxicity - hyperkalemia
check PFTs - LFTs - and TFTs
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

8. What is the mechanism of action of Ticlopidine - Clopidogrel
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
reversible SLE- like syndrome
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Beta - lactamase cleavage of Beta - lactam ring

9. How is Amphotericin B administered for fungal meningitis?
Delirium - Tremor - Nephrotoxicity
AluMINIMUM amount of feces.
reversible SLE- like syndrome
Intrathecally

10. What are three toxicities of Leuprolied?
Digitoxin 168hrs Digoxin 40 hrs
Prevents the release of ACh - Which results in muscle paralysis.
prevention of nodal arrhythmias (SVT)
1. Antiandrogen 2. Nausea 3. Vomiting

11. What antimuscarinic drug is useful for the tx of asthma
CL= (rate of elimination of drug/ Plasma drug conc.)
Ipratropium
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.

12. How can the t1/2 of INH be altered?
Fast vs. Slow Acetylators
Mg = Must go to the bathroom.
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
- Ethanol - dialysis - & fomepizole

13. What are three possible toxicities of NSAID usage?
1. Renal damage 2. Aplastic anemia 3. GI distress
hyperaldosteronism - K+ depletion - CHF
Aminoglycosides
- Methotrexate - 5 FU - 6 mercaptopurine

14. What is the mechanism of action of Probenacid used to treat chronic gout?
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Inhibits reabsorption of uric acid.
atropine - homatropine - tropicamide
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids

15. What are the clinical indications for Azole therapy?
pulmonary edema - dehydration
Systemic mycoses
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Acetylcholine esterase

16. What is the MOA of Ganciclovir?
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Acute (hours)
Inhibits CMV DNA polymerase
Tricyclic antidepressant.

17. What organisms does Griseofulvin target?
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Dopamine; causes its release from intact nerve terminals
Dermatophytes (tinea - ringworm)

18. What is the definition of zero - order kinetics? Example?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Doxycycline - because it is fecally eliminated
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Acetylcholinesterase; ACh is broken down into choline and acetate.

19. What are Aminoglycosides used for clinically?
Severe Gram - rod infections.
Beta Blockers
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Pretreat with antihistamines and a slow infusion rate

20. Resistance mechanisms for Macrolides

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21. Side effects of Isoniazid (INH)?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
carbonic anhydrase inhibitors - K+ sparing diuretics
atropine - homatropine - tropicamide
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

22. Which drug(s) cause this reaction: Cinchonism (2)?
Edrophonium
PT
- Quinidine - quinine
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

23. What are three toxicities of Propylthiouracil?
Peptic ulcer disease.
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Staphlococcus aureus

24. Antiarrhythmic class II- effects?
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Minor hepatotoxicity - Drug interactions (activates P450)
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

25. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Sulfonamides - Trimethoprim

26. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Bacitracin - Vancomycin
Babiturate.
- Nitrate - hydroxocobalamin thiosulfate

27. What is the memory key to remember Which pathway (extrinsic vs. intrinsic) and Which lab value Warfarin affects?
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Cephalosporins
Methylation of rRNA near Erythromycin's ribosome binding site

28. Bretyllium - toxicity?
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
new arrhythmias - hypotension
Methylxanthine.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

29. Which individuals are predisposed to Sulfonamide - induced hemolysis?
G6PD deficient individuals
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

30. What is the lab value used to monitor the effectiveness of Warfarin therapy?
Gram + and Anerobes
The PT.
Inhibits cell wall mucopeptide formation - Bactericidal
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

31. What is the memory aid for subunit distribution of ribosomal inhibitors?

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32. Name the Protease Inhibitors (4)
Saquinavir - Ritonavir - Indinavir - Nelfinavir
CL= (rate of elimination of drug/ Plasma drug conc.)
Modification via Acetylation
Reversible block of histamine H2 receptors

33. What is a common side effect of Misoprostol?
Diarrhea
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
- Bleomycin - amiodarone - busulfan
Onchocerciasis ('river blindness'-- rIVER- mectin)

34. For Warfarin What is the Treatment for overdose
- Corticosteroids - heparin
IV vitamin K and fresh frozen plasma
- Deferoxamine
aPTT (intrinsic pathway)

35. What are the clinical uses for 1st Generation Cephalosporins?
Benzodiazepine.
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Inhibits cell wall mucopeptide formation - Bactericidal
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

36. Why is reserpine effective in treating HTN?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
CMV Retinitis in IC pts When Ganciclovir fails
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
prevention of nodal arrhythmias (SVT)

37. What conditions would you use dantrolene?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
Only in limited amounts

38. What are two conditions in Which COX-2 inhibitors might be used?
Rheumatoid and osteoarthritis.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Potent immunosuppressive used in organ transplant recipients.

39. Name two LPL stimulators.
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Gemfibrozil - Clofibrate
Inhibits CMV DNA polymerase

40. Ca2+ channel blockers - toxicity?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Sotalol - Ibutilide - Bretylium - Amiodarone
Benzodiazepine.
cardiac depression - peripheral edema - flushing - dizziness - constipation

41. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
Tricyclic antidepressant.
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
hypertension - angina - arrhythmias
Nephrotoxicity

42. What are toxic side effects for Metronidazole?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Disulfiram - like reaction with EtOH - Headache
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
- Glucagon

43. What are the clinical uses for Imipenem/cilastatin?
post MI and digitalis induced arrhythmias
Gram + cocci - Gram - rods - and Anerobes
RESPIre
Rheumatoid and osteoarthritis.

44. What is the mechanism of action of Heparin?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Heparin catalyzes the activation of antithrombin III.
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

45. Which drug(s) cause this reaction: Adrenocortical Insufficiency
VACUUM your Bed Room'
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Beta antagonist.
- Glucocorticoid withdrawal

46. Name the steps in drug approval(4)?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Megaloblastic anemia - Leukopenia - Granulocytopenia
Resistant Gram - infections
CMV - esp in Immunocompromised patients

47. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Impairs the synthesis of vitamin K- dependent clotting factors
cardiac depression - peripheral edema - flushing - dizziness - constipation
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.

48. What is the mechanism of action of Acetaminophen?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
prevention of nodal arrhythmias (SVT)
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
- Ethosuxamide - sulfonamides - lamotrigine

49. Name three Antiarrhythmic drugs in class IC.
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Cilastatin
- Penicillin
Flecainide - Encainide - Propafenone

50. Ca2+ channel blockers - mechanism?
Rifampin
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility