USMLE Step 1 Pharmacology

Instructions:

• Answer 50 questions in 15 minutes.
• If you are not ready to take this test, you can study here.
• 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 is Griseofulvin used clinically?
With an amino acid change of D- ala D- ala to D- ala D- lac
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Oral treatment of superficial infections
sedation - depression - nasal stuffiness - diarrhea


2. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
Norepinephrine
No - hemicholinum block the uptake of Choline and thus Ach synthesis
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
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)


3. Resistance mechanisms for Aminoglycosides
Modification via Acetylation - Adenylation - or Phosphorylation
effective in torsade de pointes and digoxin toxicity
Methylation of rRNA near Erythromycin's ribosome binding site
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.


4. What is the difference in receptor affinity of epinephrine at low doses? High doses?

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5. How do you calculate maintenance dose?
Constant FRACTION eliminated per unit time.(exponential)
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Local anesthetic.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.


6. For Heparin What is the Lab value to monitor
aPTT (intrinsic pathway)
- Shifts the curve down - reduces Vmax
Delirium - Tremor - Nephrotoxicity
Ca2+ (Loops Lose calcium)


7. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
pulmonary edema - dehydration


8. A common side effects of Interferon (INF) treatment is?
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Neutropenia
- Ethosuxamide - sulfonamides - lamotrigine
collecting ducts


9. What cholinomimetics might your pt be taking for his glaucoma
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
- Phenytoin
Carbachol - pilocarpine - physostigmine - echothiophate
Inhibits reabsorption of uric acid.


10. What microorganisms is Aztreonam not effective against?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Gram + and Anerobes
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia


11. Name three K+ sparing diuretics?
Spironolactone - Triamterene - Amiloride (the K+ STAys)
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid


12. What is the loading dose formula?
- Flumazenil
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Rheumatoid and osteoarthritis.


13. Which drug(s) cause this reaction: Cough?
- ACE inhibitors (Losartan>no cough)
AV nodal cells
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Antibiotic - protein synthesis inhibitor.


14. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
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.)
Triple sulfas or SMZ
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.


15. What is a common side effect of Misoprostol?
- Methotrexate - 5 FU - 6 mercaptopurine
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Diarrhea
penicillinase resistant


16. Which diuretics increase urine K+?
Sotalol - Ibutilide - Bretylium - Amiodarone
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor


17. What is the category of drug names ending in - ipramine (e.g. Imipramine)
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Activates antithrombin III
Tricyclic antidepressant.
Methicillin - Nafcillin - and Dicloxacillin


18. What is the formula for Clearance (CL)
Potent immunosuppressive used in organ transplant recipients.
Binds to the Pyrophosphate Binding Site of the enzyme
CL= (rate of elimination of drug/ Plasma drug conc.)
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression


19. Describe first - order kinetics?
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Constant FRACTION eliminated per unit time.(exponential)
- Tricyclic antidepressants
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)


20. Mannitol - mechanism?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Digitoxin 168hrs Digoxin 40 hrs
Heparin catalyzes the activation of antithrombin III.


21. What is the main clinical use for the thrombolytics?
Increases coumadin metabolism
Early myocardial infarction.
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Binds ergosterol - Disrupts fungal membranes


22. Adverse effects of Hydralazine?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
proarrhythmic
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)


23. How is Leishmaniasis treated?
Pseudomonas species and Gram - rods
first dose orthostatic hypotension - dizziness - headache
Pentavalent Antimony
BM suppression (neutropenia - anemia) - Peripheral neuropathy


24. Name the common Nucleoside Reverse Transcriptase Inhibitors
Antileukotriene; blocks synthesis by lipoxygenase.
Severe Gram - rod infections.
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).


25. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
troponin - tropomyosin system
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Nephrotoxicity


26. What is the mechanism of Tacrolimus (FK506)?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Inhibits reabsorption of uric acid.
No - it inhibits the release of Nor Epi


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

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28. What musculo - skeletal side effects in Adults are associated with Floroquinolones?
Tendonitis and Tendon rupture
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
1. Pioglitazone 2. Rosiglitazone.
TMP- SMZ (DOC) - aerosolized pentamidine


29. What is the chemical name for Ganciclovir?
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
DHPG (dihydroxy-2- propoxymethyl guanine)
Gram + cocci - Gram - rods - and Anerobes


30. Adverse effects of Methyldopa?

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31. Antiarrhythmic class IB- effects?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Prevents the release of ACh - Which results in muscle paralysis.
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias


32. Antiarrhythmic Class III- effects?
- Act on same receptor - Full has greater efficacy
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.


33. What is the category of drug names ending in - ane (e.g. Halothane)
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Inhalational general anesthetic.
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
- Tetracycline


34. What are the side effects of Polymyxins?
Inhibits CMV DNA polymerase
Neurotoxicity - Acute renal tubular necrosis
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Inhibits cell wall mucopeptide formation - Bactericidal


35. What is the mechanism of action of Mifepristone (RU486)?
Competitive inibitor of progestins at progesterone receptors.
dry mouth - sedation - severe rebound hypertension
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
hyperaldosteronism - K+ depletion - CHF


36. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Antileukotriene; blocks leukotriene receptors.
Binding to the presynaptic alpha 2 release modulating receptors
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Paranteral (IV - SC)


37. Resistance mechanisms for Chloramphenicol
not a sulfonamide - but action is the same as furosemide
Modification via Acetylation
Small lipid - soluble molecule
INH: Injures Neurons and Hepatocytes


38. In What population does Gray Baby Syndrome occur? Why?
GET on the Metro
- Atropine & pralidoxime
Premature infants - because they lack UDP- glucuronyl transferase
Benzathine penicillin G


39. List the specific antidote for this toxin: Tricyclic antidepressants
Digoxin=urinary Digitoxin=biliary
Phenothiazine (neuroleptic - antiemetic).
Lidocaine - Mexiletine - Tocainide
- NaHCO3


40. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.


41. What is the category of drug names ending in - oxin (e.g. Digoxin)
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Keratin containing tissues - e.g. - nails
Cardiac glycoside (inotropic agent).
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species


42. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Methylation of rRNA near Erythromycin's ribosome binding site
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.
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


43. What is the category of drug names ending in - operidol (e.g. Haloperidol)
- Disulfram & also sulfonylureas - metronidazole
1. Renal damage 2. Aplastic anemia 3. GI distress
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Butyrophenone (neuroleptic).


44. What are three toxicities of Leuprolied?
1. Antiandrogen 2. Nausea 3. Vomiting
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
- B51Naloxone / naltrexone (Narcan)
Nucleosides


45. What can result due to antacid overuse?
For serious - Gram + multidrug - resistant organisms
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.


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

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47. What are common side effects of Protease Inhibitors?
Large anionic polymer - acidic
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)


48. List the specific antidote for this toxin: Iron
- Deferoxamine
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
cortical collecting tubule
loop diuretics - thiazides


49. Acetazolamide causes?

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50. ACE inhibitors - toxicity?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
thick ascending limb