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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. Toxic side effects of the Azoles?
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Beta - lactam antibiotics
Modification via Acetylation - Adenylation - or Phosphorylation

2. How is Ganciclovir activated?
Inhibits Viral DNA polymerase
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Phosphorylation by a Viral Kinase
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

3. What type of gout is treated with Colchicine?
- Tetracycline - amiodarone - sulfonamides
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Impairs the synthesis of vitamin K- dependent clotting factors
Acute gout.

4. The MOA for Chloramphenicol is?
Triple sulfas or SMZ
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Rare.
Inhibition of 50S peptidyl transferase - Bacteriostatic

5. What is the clinical use for Warfarin?
1. Pioglitazone 2. Rosiglitazone.
No - it inhibits the release of Nor Epi
Chronic anticoagulation.
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

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

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7. What is an acronym to remember Anti - TB drugs?
Norepinephrine
RESPIre
Foscarnet = pyroFosphate analog
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

8. What microorganisms are clinical indications for Tetracycline therapy?

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9. Name four HMG- CoA reductase inhibitors.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Headache - flushing - dyspepsia - blue - green color vision.
Flecainide - Encainide - Propafenone
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents

10. List some specifics of lead poisoning(4)?
Interstitial nephritis
ACIDazolamide' causes acidosis
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Sulfonamides - Trimethoprim

11. Cautions When using Amiodarone?
check PFTs - LFTs - and TFTs
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Cyclooxygenases (COX I - COX II).
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

12. Why are the Sulfonylureas inactive in IDDM (type -1)?
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Because they require some residual islet function.
Neurotoxicity - Acute renal tubular necrosis
Tricyclic antidepressant.

13. List the specific antidote for this toxin: Methemoglobin
Dermatophytes (tinea - ringworm)
- Methylene blue
- Methotrexate - 5 FU - 6 mercaptopurine
- Vitamin K & fresh frozen plasma

14. Acetazolamide - site of action?
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
proximal convoluted tubule
- Flumazenil

15. What are two toxicities associated with Cyclosporine?
Only in limited amounts
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
propanolol - esmolol - metoprolol - atenolol - timolol
Inhibits cell wall synthesis ( binds to PBP3). A monobactam

16. Describe Phase I metabolism in liver(3)?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Protease inhibitor.
RESPIre

17. What is the major side effect for Carbenicillin - Piperacillin - and Ticarcillin?
- Fluoroquinolones
Hypersensitivity reactions
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

18. MOA: Block nucleotide synthesis
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Onchocerciasis ('river blindness'-- rIVER- mectin)
Reversible block of histamine H2 receptors
Sulfonamides - Trimethoprim

19. Name the common Nucleoside Reverse Transcriptase Inhibitors
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

20. Describe Phase II metabolism in liver(3)?
Modification via Acetylation - Adenylation - or Phosphorylation
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Treatment of infertility.
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

21. What drugs target anticholinesterase
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Saquinavir - Ritonavir - Indinavir - Nelfinavir

22. Which drug(s) cause this reaction: Osteoporosis (2)?
- Corticosteroids - heparin
Stimulates beta adrenergic receptors
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Abortifacient.

23. Which cancer drugs work at the level of proteins(2)?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Hypersensitivity reactions
- Vinca alkaloids(inhibit MT) - Paclitaxel
sedation - sleep alterations

24. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
- Physostigmine salicylate
Penicillin.
Same as penicillin. Extended spectrum antibiotics

25. IV Penicillin
Penicillin - G
Carbachol - pilocarpine - physostigmine - echothiophate
Constant FRACTION eliminated per unit time.(exponential)
Penicillin.

26. Antimicrobial prophylaxis for PCP
- Tetracycline - amiodarone - sulfonamides
TMP- SMZ (DOC) - aerosolized pentamidine
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.
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

27. List the mechanism - clinical use - & toxicity of Cisplatin.
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

28. Adverse effects of ganglionic blockers?
Erythromycin - Azithromycin - Clarithromycin
Chronic (weeks or months)
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
- Normalize K+ - Lidocaine - & Anti - dig Mab

29. Antiarrhythmic class IC- toxicity?
GET on the Metro
torsade de pointes
proarrhythmic
Butyrophenone (neuroleptic).

30. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Antifungal.
Ceftriaxone

31. Your patient wants an effective drug to treat his motion sickness - What would you prescribe
The PTT.
Blood
Scopolamine
Anaerobes

32. Name three Antiarrhythmic drugs in class IV.
Succinylcholine
Binds to the Pyrophosphate Binding Site of the enzyme
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Verapamil - Diltiazem - Bepridil

33. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
Acetylcholine esterase
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
is resistant

34. What are the clinical uses for 3rd Generation Cephalosporins?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Cephalosporins
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

35. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
- Normalize K+ - Lidocaine - & Anti - dig Mab
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
- Vitamin K & fresh frozen plasma

36. What is the category of drug names ending in - olol (e.g. Propranolol)
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Beta antagonist.
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.

37. What are three toxicities of Leuprolied?
NO
Headache - flushing - dyspepsia - blue - green color vision.
The PTT.
1. Antiandrogen 2. Nausea 3. Vomiting

38. What is the category - desired effect - and possible mechanism of Theophylline in treating Asthma?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Hypersensitivity reactions
Epinephirine(Alpha1 -2 and Beta 1 -2)

39. Which diuretics decrease urine Ca2+?
thiazides - amiloride
carbonic anhydrase inhibitors - K+ sparing diuretics
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

40. What microorganisms are Aminoglycosides ineffective against?
Anaerobes
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

41. What is a possible toxicity of Ticlopidine - Clopidogrel usage?
Bethanechol - Neostigmine - physostigmine
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

42. Which drug(s) cause this reaction: Thrombotic complications?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
- Oral Contraceptives
Sildenafil fills the penis
Blocks Influenza A and RubellA; causes problems with the cerebellA

43. What is used to reverse the action of Heparin?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
It must be Phosphorylated by Viral Thymidine Kinase

44. How are Interferons (INF) used clinically?

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45. How does dantrolene work?
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Decreased uptake or Increased transport out of cell
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

46. What are the side effects of Polymyxins?
- Clindamycin
Neurotoxicity - Acute renal tubular necrosis
Acute (hours)
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

47. What is the MOA of Ribavirin?
Headache - flushing - dyspepsia - blue - green color vision.
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion

48. Adverse effects of Hydralazine?
loop diuretics - spironolactone
cardiac depression - peripheral edema - flushing - dizziness - constipation
- Atropine & pralidoxime
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

49. Explain differences between full and partial agonists(2).
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
- Quinidine - quinine
CMV Retinitis in IC pts When Ganciclovir fails
- Act on same receptor - Full has greater efficacy

50. What is the mechanism of action of Clomiphene?
Ibuprofen - Naproxen - and Indomethacin
proarrhythmic
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
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.