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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. How do you calculate maintenance dose?
- Alkalate DNA - Brain tumors - CNS toxicity
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

2. What is the category of drug names ending in - oxin (e.g. Digoxin)
Cardiac glycoside (inotropic agent).
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
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

3. Decrease Digitoxin dose in renal failure?
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.
NO
Sildenafil fills the penis
- Fluoroquinolones

4. Resistance mechanisms for Chloramphenicol
Modification via Acetylation
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Succinylcholine

5. What is combination TMP- SMZ used to treat?
Increases coumadin metabolism
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

6. What are two toxicities of the Glitazones?
decrease conduction velocity - increase ERP - increase PR interval
Headache - flushing - dyspepsia - blue - green color vision.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
1. Weight gain 2. Hepatotoxicity (troglitazone)

7. Beta Blockers - CV toxicity?
Potent immunosuppressive used in organ transplant recipients.
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Competitive inibitor of progestins at progesterone receptors.
bradycardia - AV block - CHF

8. Dobutamine used for the tx of shock acts on Which receptors
- Lithium
toxic
Pretreat with antihistamines and a slow infusion rate
Beta1 more than B2

9. What are common toxicities associated with Tetracyclines?

10. What is the MOA for the Azoles?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Penicillin.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Inhibit Ergosterol synthesis

11. What are common side effects of RT Inhibitors?
Indomethacin is used to close a patent ductus arteriosus.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
BM suppression (neutropenia - anemia) - Peripheral neuropathy

12. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
It affects beta receptors equally and is used in AV heart block (rare).
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
GI side effects. (Indomethacin is less toxic - more commonly used.)

13. What is the mechanism of action of Clomiphene?
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
- Vitamin K & fresh frozen plasma
Hypersensitivity reactions
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.

14. For Heparin What is the Ability to inhibit coagulation in vitro
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Lipoxygenase
Yes

15. Which drug(s) cause this reaction: Adrenocortical Insufficiency
Decreased uptake or Increased transport out of cell
Inhibits cell wall mucopeptide formation - Bactericidal
- Glucocorticoid withdrawal
Severe Gram - rod infections.

16. What are two clinical uses of Azathioprine?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
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.
Mebendazole/Thiabendazole - Pyrantel Pamoate

17. What is a common side effect of Misoprostol?
Diarrhea
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
post MI and digitalis induced arrhythmias

18. What are three toxicities of Leuprolied?
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
GI discomfort
1. Antiandrogen 2. Nausea 3. Vomiting
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.

19. Adverse effects of Reserpine?
- EDTA - dimercaprol - succimer - & penicillamine
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Neurotoxicity - Acute renal tubular necrosis
sedation - depression - nasal stuffiness - diarrhea

20. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
Methylxanthine.
amphetamine and ephedrine
viral kinase
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil

21. What are three clinical uses of the Leuprolide?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
TMP- SMZ (DOC) - aerosolized pentamidine
Fast vs. Slow Acetylators
- Protamine

22. What are three clinical uses of the NSAIDs?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Doxycycline - because it is fecally eliminated
Increases coumadin metabolism

23. Ca2+ channel blockers - toxicity?
Disulfiram - like reaction with EtOH - Headache
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
cardiac depression - peripheral edema - flushing - dizziness - constipation

24. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Haloperidol - chlorpromazine - reserpine - MPTP
Dermatophytes (tinea - ringworm)

25. Which drug(s) cause this reaction: Pseudomembranous colitis?
Neutropenia
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
- Clindamycin
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

26. List the specific antidote for this toxin: Lead
severe hypertension - CHF
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
- EDTA - dimercaprol - succimer - & penicillamine

27. What are the products and their toxicities of the metabolism of Methanol by / alcohol dehydrogenase?
- Antipsychotics
- Formaldehyde & formic acid - severe acidosis & retinal damage
Cephalosporins
Nitrates

28. What are the four conditions in Which Omeprazole - Lansoprazole is used?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Rapid (seconds)
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
torsade de pointes - excessive Beta block

29. What are four conditions in Which H2 Blockers are used clinically?
Praziquantel
Rifampin
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
- Methotrexate - 5 FU - 6 mercaptopurine

30. What do Aminoglycosides require for uptake?
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Cilastatin
Oxygen
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

31. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
Ataxia - Dizziness - Slurred speech
- Alkalate DNA - Brain tumors - CNS toxicity
Tricyclic antidepressant.
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.

32. Adverse effects of beta - blockers?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
decrease
Neutropenia
Anaerobes

33. What is the clinical use for Sildenafil (Viagra)?
Digitoxin 70% Digoxin 20-40%
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Erectile dysfunction.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

34. Ganciclovir associated toxicities?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
- Methotrexate - 5 FU - 6 mercaptopurine
Beta lactams - inhibit cell wall synthesis - Bactericidal
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

35. Which of epi - norepi - or isoproterenol results in bradycardia?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Norepinephrine
Long.
Hypersensitivity reactions

36. What is the MOA of Ganciclovir?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Inhibits CMV DNA polymerase

37. What class of drug is echothiophate? What is its indication?
anticholinesterase glaucoma
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
As an anticholinesterase it increases endogenous ACh and thus increases strength.
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

38. What is the memory key for Isoniazid (INH) toxicity?
INH: Injures Neurons and Hepatocytes
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Constant FRACTION eliminated per unit time.(exponential)
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

39. What are three possible toxicities of NSAID usage?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
1. Renal damage 2. Aplastic anemia 3. GI distress
atropine - homatropine - tropicamide

40. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
Polymyxins
Hydralazine and Minoxidil
AluMINIMUM amount of feces.
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)

41. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
GI side effects. (Indomethacin is less toxic - more commonly used.)
Inhibit viral DNA polymerase
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
cardiac depression - peripheral edema - flushing - dizziness - constipation

42. Antiarrhythmic class II- mechanism?
first dose orthostatic hypotension - dizziness - headache
- Ethosuxamide - sulfonamides - lamotrigine
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux

43. What is the lab value used to monitor the effectiveness of Heparin therapy?
The PTT.
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Because they require some residual islet function.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

44. MOA: Bactericidal antibiotics
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
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)
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

45. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Oral treatment of superficial infections
Competitive inibitor of progestins at progesterone receptors.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Polymyxin B - Polymyxin E

46. What are the products and their toxicities of the metabolism of Ethylene Glycol by / alcohol dehydrogenase?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
GI upset - Superinfections - Skin rashes - Headache - Dizziness
- Oxalic acid - Acidosis & nephrotoxicity
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

47. What is the formula for Volume of distribution (Vd)
Vd= (Amt. of drug in body/ Plasma drug conc.)
first dose orthostatic hypotension - dizziness - headache
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Praziquantel

48. Name the common Aminoglycosides (5)
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Disulfiram - like reaction with EtOH - Headache
Increases coumadin metabolism
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

49. Antiarrhythmic class IB- effects?
Decreases synthesis of Mycolic Acid
Buy AT 30 - CELL at 50'
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

50. What is the mechanism of action of Ticlopidine - Clopidogrel
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
- Disulfram & also sulfonylureas - metronidazole