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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. How can the t1/2 of INH be altered?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
- Formaldehyde & formic acid - severe acidosis & retinal damage
Acute (hours)
Fast vs. Slow Acetylators

2. What is the memory key to remember Which pathway (extrinsic vs. intrinsic) and Which lab value Warfarin affects?
severe hypertension - CHF
Same as penicillin. Extended spectrum antibiotics
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

3. What are four conditions in Which H2 Blockers are used clinically?
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
- Tetracycline
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

4. What are four H2 Blockers?
Give an antichloinesterase - neostigmine - edrophonium - etc
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Activates antithrombin III
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

5. Bretyllium - toxicity?
Antifungal.
new arrhythmias - hypotension
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
toxic

6. Hydralazine - toxicity?
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Spironolactone - Triamterene - Amiloride (the K+ STAys)
- Nitrate - hydroxocobalamin thiosulfate
compensatory tachycardia - fluid retention - lupus - like syndrome

7. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
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.
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

8. Which drug(s) cause this reaction: Cutaneous flushing (4)?
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Niacin - Ca++ channel blockers - adenosine - vancomycin
hyperaldosteronism - K+ depletion - CHF
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.

9. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
- Bleomycin - amiodarone - busulfan
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Penicillin - G
Binding to the presynaptic alpha 2 release modulating receptors

10. What are four Sulfonylureas?
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Neurotoxicity - Acute renal tubular necrosis
- Nitrate - hydroxocobalamin thiosulfate
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.

11. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Inhibits reabsorption of uric acid.
Protease Inhibitors and Reverse Transcriptase Inhibitors
Those patients who are taking nitrates.
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

12. Acetazolamide - site of action?
- NaHCO3
As an anticholinesterase it increases endogenous ACh and thus increases strength.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
proximal convoluted tubule

13. Resistance mechanisms for Chloramphenicol
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Modification via Acetylation
DOC in diagnosing and abolishing AV nodal arrhythmias
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

14. Which receptors does phenylephrine act upon?
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
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.
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Tendonitis and Tendon rupture

15. What is the category and mechanism of action of Zileuton in Asthma treatment?
No - warfarin - unlike heparin - can cross the placenta.
1. Pioglitazone 2. Rosiglitazone.
Antileukotriene; blocks synthesis by lipoxygenase.
Rash - Pseudomembranous colitis

16. 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
Blood
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Aminoglycosides

17. What are Fluoroquinolones indicated for? (3)
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
Teratogenic - Carcinogenic - Confusion - Headaches
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Ataxia - Dizziness - Slurred speech

18. How does a competitive antagonist effect an agonist?
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
hypertension - CHF - diabetic renal disease
Oxygen
- Shifts the curve to the right - increases Km

19. Explain potency in relation to full and partial agonists(2).
Abortifacient.
DHPG (dihydroxy-2- propoxymethyl guanine)
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Local anesthetic.

20. What is the memory key for Metronidazole's clinical uses?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
GET on the Metro
Nifedipine - Verapamil - Diltiazem

21. What enzyme is responsible for the degredation of Ach
Acetylcholine esterase
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
competitive inhibirot of aldosterone in the cortical collecting tubule
Decreases synthesis of Mycolic Acid

22. What are two processes Corticosteroids inhibit leading to decreased inflammation?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Nifedipine - Verapamil - Diltiazem
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Captopril - Enalapril - Lisinopril

23. List the specific antidote for this toxin: Warfarin
Pentavalent Antimony
Foscarnet = pyroFosphate analog
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
- Vitamin K & fresh frozen plasma

24. What beta 2 agonist will help your 21yo Astma pt?
- Ethosuxamide - sulfonamides - lamotrigine
Tendonitis and Tendon rupture
Albuterol - tertbutaline
Norepinephrine

25. What is the mechanism of action of Colchicine used to treat acute gout?
Protease Inhibitors and Reverse Transcriptase Inhibitors
Abortifacient.
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Used in combination therapy with SMZ to sequentially block folate synthesis

26. Cautions When using Amiodarone?
check PFTs - LFTs - and TFTs
Enterobacter
- Corticosteroids - heparin
Hypersensitivity reactions

27. Adverse effects of Guanethidine?
Oxygen
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.)
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
DHPG (dihydroxy-2- propoxymethyl guanine)

28. For Heparin What is the Site of action
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Blood
ACIDazolamide' causes acidosis

29. What are the Macrolides used for clinically?
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Hydralazine and Minoxidil
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

30. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Norepinephrine
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.

31. What is the clinical use for Penicillin?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
reversible SLE- like syndrome

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

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33. How would you reverse the effect of a neuromuscular blocking agent?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
CMV - esp in Immunocompromised patients
- aminoglycosides - loop diuretics - cisplatin
Give an antichloinesterase - neostigmine - edrophonium - etc

34. What is the MOA of Ganciclovir?
Ceftriaxone
Inhibits CMV DNA polymerase
- Shifts the curve down - reduces Vmax
Hemolytic anemia

35. What are four thrombolytics?
No - warfarin - unlike heparin - can cross the placenta.
- polymyxins
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.

36. Does Heparin have a long - medium - or short half life?
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Short.
scopolamine
Large anionic polymer - acidic

37. What is the mechanism of action of Mifepristone (RU486)?
Abortifacient.
Methicillin - Nafcillin - and Dicloxacillin
Beta lactams - inhibit cell wall synthesis - Bactericidal
Competitive inibitor of progestins at progesterone receptors.

38. Beta Blockers - CV toxicity?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
prevention of nodal arrhythmias (SVT)
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
bradycardia - AV block - CHF

39. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

40. What is the possible mechanism and effect of Metformin in treating diabetes?
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Ibuprofen - Naproxen - and Indomethacin
GI upset

41. What do Aminoglycosides require for uptake?
Choline acetyltransferase
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Oxygen
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

42. What is a possible result of overdose of Acetaminophen?
Modification via Acetylation - Adenylation - or Phosphorylation
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Staphlococcus aureus

43. What are three clinical uses of the Leuprolide?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Beta Blockers
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Foscarnet = pyroFosphate analog

44. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
- Ethosuxamide - sulfonamides - lamotrigine
Vd= (Amt. of drug in body/ Plasma drug conc.)
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

45. What is the mecanism of action of Sucralfate?
Penicillin.
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
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.
Prevents the release of Ca from SR of skeletal muscle

46. What is the category of drug names ending in - zosin (e.g. Prazosin)
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Alpha -1 antagonist

47. Hydrochlorothiazide - mechanism?
Primaquine
Penicillin - G
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.

48. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
Minor hepatotoxicity - Drug interactions (activates P450)
scopolamine
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
pulmonary edema - dehydration

49. Why is reserpine effective in treating HTN?
Gram + and Anerobes
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Potent immunosuppressive used in organ transplant recipients.
- Daunorubicin & Doxorubicin

50. Procainamide - toxicity?
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
reversible SLE- like syndrome