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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. For Warfarin What is the Onset of action
Phenothiazine (neuroleptic - antiemetic).
Slow - limited by half lives of clotting factors
Decreased uptake or Increased transport out of cell
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic

2. What drug is used to diagnose myasthenia gravis?
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
edrophonium (extremely short acting anticholinesterase)
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Pituitary hormone.

3. Which drug increases Sys BP w/o affecting Pulse Pressure
Ipratropium
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Epinephrine
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

4. List the specific antidote for this toxin: Digitalis
- Normalize K+ - Lidocaine - & Anti - dig Mab
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
fetal renal toxicity - hyperkalemia
Scopolamine

5. Mannitol - clinical use?
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
- Shifts the curve down - reduces Vmax
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

6. Explain pH dependent urinary drug elimination?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
1. Acarbose 2. Miglitol
GI upset
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

7. How is Rifampin used clinically?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Decreases synthesis of Mycolic Acid
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Forms toxic metabolites in the bacterial cell - Bactericidal

8. Aztreonam ________ to penicillinase
The only local anesthetic with vasoconstrictive properties.
is resistant
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Ataxia - Dizziness - Slurred speech

9. List some specifics of lead poisoning(4)?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Bethanechol - Neostigmine - physostigmine
Activates antithrombin III
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

10. Dobutamine used for the tx of shock acts on Which receptors
Beta1 more than B2
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
Antifungal.

11. Which RT inhibitors cause Lactic Acidosis?
Nucleosides
- Phenytoin
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

12. What is the clinical use for Warfarin?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Chronic anticoagulation.
- Protamine
VACUUM your Bed Room'

13. What is the category and mechanism of action of Zafirlukast in Asthma treatment?
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Because they require some residual islet function.
Antileukotriene; blocks leukotriene receptors.

14. What are the clinical indications for Azole therapy?
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)
These B-2 agonists cause respiratory smooth muscle to relax.
Ca2+ (Loops Lose calcium)
Systemic mycoses

15. What is the MOA for the Aminoglycosides?
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
Headache - flushing - dyspepsia - blue - green color vision.
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

16. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Hydralazine and Minoxidil
Antileukotriene; blocks synthesis by lipoxygenase.
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

17. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Resistant Gram - infections
Tricyclic antidepressant.
Premature infants - because they lack UDP- glucuronyl transferase
- Nitrate - hydroxocobalamin thiosulfate

18. What is the category of drug names ending in - tropin (e.g. Somatotropin)
Pituitary hormone.
- Quinidine - quinine
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Onchocerciasis ('river blindness'-- rIVER- mectin)

19. What is the clinical use for Penicillin?
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Scopolamine
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
1. Antiandrogen 2. Nausea 3. Vomiting

20. List the mechanism - clinical use - & toxicity of Doxorubicin.

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21. Mannitol - contraindications?
anuria - CHF
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Digitoxin 70% Digoxin 20-40%
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

22. What is the mechanism of action of Warfarin (Coumadin)?
Amphotericin B - Nystatin - Fluconazole/azoles
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
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.
- NaHCO3

23. Acetazolamide - mechanism?
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Short.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

24. What is the memory key for organisms treated with Tetracyclines?

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25. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
propanolol - esmolol - metoprolol - atenolol - timolol
- inhibits HGPRT (pur. Syn.) - Luk - Lymph

26. Cocaine shares is mechanism of action with What antidepressant
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
TCA
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid

27. What is the mechanism of action of Cyclosporine?
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
very short acting
Slow - limited by half lives of clotting factors
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

28. What is the category of drug names ending in - caine (e.g. Lidocaine)
Nevirapine - Delavirdine
Local anesthetic.
CMV Retinitis in IC pts When Ganciclovir fails
Verapamil - Diltiazem - Bepridil

29. What are the major structural differences between Penicillin and Cephalosporin?
Diarrhea
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)
Triple sulfas or SMZ
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

30. What is the mechanism of action of Clomiphene?
INH: Injures Neurons and Hepatocytes
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.
BM suppression (neutropenia - anemia) - Peripheral neuropathy
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

31. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
IV vitamin K and fresh frozen plasma
- Bleomycin - amiodarone - busulfan
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Because they require some residual islet function.

32. For Heparin What is the Onset of action
Rapid (seconds)
Inhibit Ergosterol synthesis
all of them
proximal convoluted tubule - thin descending limb - and collecting duct

33. In What population does Gray Baby Syndrome occur? Why?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Premature infants - because they lack UDP- glucuronyl transferase
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Give an antichloinesterase - neostigmine - edrophonium - etc

34. Does Ampicillin or Amoxicillin have a greater oral bioavailability?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- Ethosuxamide - sulfonamides - lamotrigine
GI upset - Superinfections - Skin rashes - Headache - Dizziness
AmOxicillin has greater Oral bioavailability

35. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
- NaHCO3
With an amino acid change of D- ala D- ala to D- ala D- lac

36. What is the MOA for the Fluoroquinolones?
- Act on same receptor - Full has greater efficacy
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Beta - lactamase cleavage of Beta - lactam ring
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)

37. Furosemide - clinical use?
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Chronic Hepatitis A and B - Kaposi's Sarcoma
Reversible block of histamine H2 receptors

38. What populations are Floroquinolones contraindicated in? Why?
- Lithium
Pregnant women - Children; because animal studies show Damage to Cartilage
TMP- SMZ (DOC) - aerosolized pentamidine
Resistant Gram - infections

39. Resistance mechanisms for Chloramphenicol
- Alkalinize urine & dialysis
- Oxalic acid - Acidosis & nephrotoxicity
Modification via Acetylation
As an anticholinesterase it increases endogenous ACh and thus increases strength.

40. What is the MOA of Aztreonam?
- Dimercaprol - succimer
Na/K ATPase
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Aminoglycosides

41. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
Prophylaxis for Influenza A - Rubella; Parkinson's disease
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Pretreat with antihistamines and a slow infusion rate

42. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- Tamoxifen
- Ammonium Chloride
Cyclooxygenases (COX I - COX II).

43. What are common toxicities associated with Tetracyclines?

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44. What are the clinical indications for neostigmine?
With an amino acid change of D- ala D- ala to D- ala D- lac
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
DHPG (dihydroxy-2- propoxymethyl guanine)

45. What are Polymyxins used for?
Resistant Gram - infections
- Shifts the curve down - reduces Vmax
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Ca2+ (Loops Lose calcium)

46. Antiarrhythmic class IA effects?
Onchocerciasis ('river blindness'-- rIVER- mectin)
- Tamoxifen
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Heparin catalyzes the activation of antithrombin III.

47. ACE inhibitors - mechanism?
Blocks Influenza A and RubellA; causes problems with the cerebellA
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- Vinca alkaloids(inhibit MT) - Paclitaxel
It inhibits release of NE.

48. What is the clinical use of Mifepristone (RU486)?
Abortifacient.
- Daunorubicin & Doxorubicin
- Steroids - Tamoxifen
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

49. How is Ganciclovir used clinically?
Ibuprofen - Naproxen - and Indomethacin
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
CMV - esp in Immunocompromised patients
Indomethacin is used to close a patent ductus arteriosus.

50. What is are two clinical uses of Cyclosporine?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Carbenicillin - Piperacillin - and Ticarcillin
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)