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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. What is the mechanism of action of Sildenafil (Viagra)?
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

2. Can Heparin be used during pregnancy?
TMP- SMZ
Yes - it does not cross the placenta.
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
hypertension - angina - arrhythmias

3. What is the category and mechanism of action of Zileuton in Asthma treatment?
Antileukotriene; blocks synthesis by lipoxygenase.
toxic
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
local anesthetic. CNS stimulation or depression. CV depression.

4. What are Polymyxins used for?
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Resistant Gram - infections
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)

5. What are toxic side effects for Metronidazole?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
AluMINIMUM amount of feces.
Disulfiram - like reaction with EtOH - Headache
Inhibition of 50S peptidyl transferase - Bacteriostatic

6. MOA: Block DNA topoisomerases
- Normalize K+ - Lidocaine - & Anti - dig Mab
Quinolones
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
PT

7. What populations are Floroquinolones contraindicated in? Why?
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
prevention of nodal arrhythmias (SVT)
Pregnant women - Children; because animal studies show Damage to Cartilage
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

8. ADH antagonists - site of action?
Pentavalent Antimony
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- Fluoroquinolones
collecting ducts

9. Adverse effects of Nifedipine - verapamil?
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Forms toxic metabolites in the bacterial cell - Bactericidal
dizziness - flushing - constipation (verapamil) - nausea
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux

10. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
dizziness - flushing - constipation (verapamil) - nausea
No - hemicholinum block the uptake of Choline and thus Ach synthesis
fetal renal toxicity - hyperkalemia

11. What is the possible mechanism and effect of Metformin in treating diabetes?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Pseudomonas species and Gram - rods
Decreases synthesis of Mycolic Acid
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

12. Adverse effects of Captopril?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
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.
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

13. What is the category and mechanism of action of Zafirlukast in Asthma treatment?
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Digitoxin>95% Digoxin 75%
Antileukotriene; blocks leukotriene receptors.
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

14. What is the MOA of Ganciclovir?
hyperaldosteronism - K+ depletion - CHF
Because they require some residual islet function.
Inhibits CMV DNA polymerase
Short.

15. What cholinergic inhibitor acts by directly inhibiting Ach release at the presynaptic terminal
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Captopril - Enalapril - Lisinopril
Botulinum

16. How is Amphotericin B used clinically?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
The only local anesthetic with vasoconstrictive properties.
Chronic anticoagulation.

17. Which drug(s) cause this reaction: Atropine - like side effects?
Carbachol - pilocarpine - physostigmine - echothiophate
- Tricyclic antidepressants
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
No - it inhibits the release of Nor Epi

18. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Non - Nucleosides
Benzodiazepine.
The PT.
Antifungal.

19. For Heparin What is the Structure
With an amino acid change of D- ala D- ala to D- ala D- lac
Antileukotriene; blocks synthesis by lipoxygenase.
Large anionic polymer - acidic
- Disulfram & also sulfonylureas - metronidazole

20. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
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.
- Clindamycin
INH: Injures Neurons and Hepatocytes

21. What is are two clinical uses of Cyclosporine?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
loop diuretics - thiazides

22. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
bradycardia - AV block - CHF
Leukotrienes increasing bronchial tone.
Epinephirine(Alpha1 -2 and Beta 1 -2)
thiazides - amiloride

23. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Headache - flushing - dyspepsia - blue - green color vision.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.

24. What are the nondepolarizing neuromuscular blocking drugs?
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium

25. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
Inhibits CMV DNA polymerase
Rare.
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
proarrhythmic

26. How does NE modulate its own release? What other neurotransmitter has this same effect?
- N- acetylcystine
all of them
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity

27. What are two conditions in Which COX-2 inhibitors might be used?
Rheumatoid and osteoarthritis.
- polymyxins
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
VACUUM your Bed Room'

28. List the specific antidote for this toxin: Salicylates
Local anesthetic.
- Alkalinize urine & dialysis
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
It affects beta receptors equally and is used in AV heart block (rare).

29. What is the clinical use for Sucralfate?
Peptic ulcer disease.
Modification via Acetylation - Adenylation - or Phosphorylation
Phosphorylation by a Viral Kinase
Tricyclic antidepressant.

30. Adverse effects of Hydrochlorothiazide?
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- Flumazenil
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

31. What is the mechanism of Leuprolide?
- Glucagon
Hypersensitivity reactions
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
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone

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

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33. Name the Protease Inhibitors (4)
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
anticholinesterase glaucoma
Saquinavir - Ritonavir - Indinavir - Nelfinavir

34. What parasitic condition is treated with Ivermectin?

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35. Which drug(s) cause this reaction: P450 inhibition(6)?
- Haloperidol - chlorpromazine - reserpine - MPTP
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
- polymyxins

36. Mannitol - contraindications?
anuria - CHF
- B51Naloxone / naltrexone (Narcan)
Saquinavir - Ritonavir - Indinavir - Nelfinavir
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)

37. K+- clinical use?
Nifedipine - Verapamil - Diltiazem
depresses ectopic pacemakers - especially in digoxin toxicity
- Chloramphenicol
cross - allergenic

38. Does Warfarin have a long - medium - or short half life?
Long.
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Interstitial nephritis
- Oral Contraceptives

39. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
edrophonium (extremely short acting anticholinesterase)
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

40. What is the category of drug names ending in - olol (e.g. Propranolol)
hyperaldosteronism - K+ depletion - CHF
Stimulates beta adrenergic receptors
Beta antagonist.
- Steroids - Tamoxifen

41. What is the mechanism of action of Misoprostol?
Protamine sulfate
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Babiturate.
Carbachol - pilocarpine - physostigmine - echothiophate

42. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
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.)
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Due to the presence of a bulkier R group

43. What is the category of drug names ending in - azine (e.g. Chlorpromazine)
Norepinephrine
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Phenothiazine (neuroleptic - antiemetic).

44. What is the memory key for the effect of aluminum hydroxide overuse?
DOC in diagnosing and abolishing AV nodal arrhythmias
AluMINIMUM amount of feces.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
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.)

45. Which drug(s) cause this reaction: Cough?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
- ACE inhibitors (Losartan>no cough)
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

46. What is the MOA for the Azoles?
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
Protamine sulfate
Inhibit Ergosterol synthesis
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression

47. How do you treat coma in the ER (4)?
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Because they require some residual islet function.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Nitrates

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

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49. How is Ganciclovir activated?
Phosphorylation by a Viral Kinase
- Vinca alkaloids(inhibit MT) - Paclitaxel
- Lithium
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

50. Aztreonam ________ to penicillinase
Neomycin
is resistant
Hypersensitivity reactions
Suramin