USMLE Step 1 Pharmacology

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. MOA: Block peptidoglycan synthesis
CMV - esp in Immunocompromised patients
Bacitracin - Vancomycin
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.


2. Explain potency in relation to full and partial agonists(2).
Rare.
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
INH: Injures Neurons and Hepatocytes
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.


3. Ca2+ channel blockers - site of action?
Dopamine
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Cell membrane Ca2+ channels of cardiac sarcomere
Methicillin - Nafcillin - and Dicloxacillin


4. What is combination TMP- SMZ used to treat?
AV nodal cells
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
H2 antagonist
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor


5. For Warfarin What is the Onset of action
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Slow - limited by half lives of clotting factors
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- Alkalate DNA - Brain tumors - CNS toxicity


6. What are common toxic side effects of Sulfonamides? (5)
Liver
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
ARF - shock - drug overdose - decrease intracranial/intraocular pressure


7. What is the receptor affinity and clinical use of isoproterenol?
Ganciclovir is more toxic to host enzymes
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
It affects beta receptors equally and is used in AV heart block (rare).
torsade de pointes - excessive Beta block


8. Describe Phase I metabolism in liver(3)?
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.
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
block Na+ channels in the cortical collecting tubule
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)


9. Guanethidine enhances the release of Norepi?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
Rifampin
No - it inhibits the release of Nor Epi


10. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
GI side effects. (Indomethacin is less toxic - more commonly used.)
toxic
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas


11. For Warfarin What is the Mechanism of action
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Impairs the synthesis of vitamin K- dependent clotting factors
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Ca2+ (Loops Lose calcium)


12. What drug is given for Pneumocystis carinii prophylaxis?
Increase target cell response to insulin.
Pentamidine
Antibiotic - protein synthesis inhibitor.
Antifungal.


13. Can Heparin be used during pregnancy?
Yes - it does not cross the placenta.
Same as penicillin. Extended spectrum antibiotics
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types


14. Adverse effects of Hydrochlorothiazide?
Primaquine
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
propanolol - esmolol - metoprolol - atenolol - timolol
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides


15. What microorganisms is Aztreonam not effective against?
Gram + and Anerobes
Activates antithrombin III
Chronic anticoagulation.
cholestyramine - colestipol


16. What is the clinical utility of cocaine?
The only local anesthetic with vasoconstrictive properties.
Aminoglycosides
Inhibits reabsorption of uric acid.
dizziness - flushing - constipation (verapamil) - nausea


17. Hydralazine - toxicity?
Blood
compensatory tachycardia - fluid retention - lupus - like syndrome
Ganciclovir is more toxic to host enzymes
propanolol - esmolol - metoprolol - atenolol - timolol


18. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
No - hemicholinum block the uptake of Choline and thus Ach synthesis
- Shifts the curve down - reduces Vmax
- Methotrexate - 5 FU - 6 mercaptopurine


19. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Staphlococcus aureus
Succinylcholine
physostigmine


20. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
- Hydralazine - Procainamide - INH - phenytoin
- Corticosteroids - heparin
Binding to the presynaptic alpha 2 release modulating receptors
Aminoglycosides


21. Name three ACE inhibitors?
Increase target cell response to insulin.
ACIDazolamide' causes acidosis
Captopril - Enalapril - Lisinopril
for RSV


22. Cautions When using Amiodarone?
Same as penicillin. Act as narrow spectrum antibiotics
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Anaerobes
check PFTs - LFTs - and TFTs


23. Does Warfarin have a long - medium - or short half life?
cyanide toxicity (releases CN)
Sulfonamides - Trimethoprim
Long.
- Disulfram & also sulfonylureas - metronidazole


24. Name two LPL stimulators.
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Gemfibrozil - Clofibrate
- Cloazapine - carbamazapine - colchicine - PTU


25. How is Amantadine used clinically?


26. Adverse effects of Nifedipine - verapamil?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
dizziness - flushing - constipation (verapamil) - nausea
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
hypertension - angina - arrhythmias


27. What are three complications of Warfarin usage?
Beta Blockers
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Give an antichloinesterase - neostigmine - edrophonium - etc
Headache - flushing - dyspepsia - blue - green color vision.


28. Ca2+ channel blockers - clinical use?
hypertension - angina - arrhythmias
- Quinidine - quinine
- Vitamin K & fresh frozen plasma
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors


29. What can result due to antacid overuse?
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Alpha -1 antagonist
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
TCA


30. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Severe Gram - rod infections.
Hypersensitivity reactions
Tricyclic antidepressant.


31. Which of epi - norepi - or isoproterenol results in bradycardia?
Hypersensitivity reactions
Abortifacient.
Ipratropium
Norepinephrine


32. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
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.)
- Ethanol - dialysis - & fomepizole
Pregnant women - Children; because animal studies show Damage to Cartilage
Due to the presence of a bulkier R group


33. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- Haloperidol - chlorpromazine - reserpine - MPTP
Albuterol - tertbutaline
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic


34. List the mechanism - clinical use - & toxicity of Cisplatin.
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Same as penicillin. Act as narrow spectrum antibiotics
Pentavalent Antimony
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.


35. What is the mechanism of action of Warfarin (Coumadin)?
IV vitamin K and fresh frozen plasma
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.
INH: Injures Neurons and Hepatocytes
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole


36. Do Tetracyclines penetrate the CNS?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
AmOxicillin has greater Oral bioavailability
Only in limited amounts


37. What are two mechanisms of action of Propythiouracil?
Sulfonamides - Trimethoprim
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Babiturate.


38. Common toxicities associated with Griseofulvin?
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Teratogenic - Carcinogenic - Confusion - Headaches


39. Name the common Azoles
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole


40. What is the memory key involving the '4 R's of Rifampin?'
- Isoniazid
Small lipid - soluble molecule
- Steroids - Tamoxifen
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone


41. Which antimuscarinic agents are used in producing mydriasis and cycloplegia?
The only local anesthetic with vasoconstrictive properties.
atropine - homatropine - tropicamide
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
- Ethanol - dialysis - & fomepizole


42. What are three unwanted effects of Mifepristone?
TMP- SMZ (DOC) - aerosolized pentamidine
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Interstitial nephritis
sedation - depression - nasal stuffiness - diarrhea


43. What cholinergic inhibitor acts by directly inhibiting Ach release at the presynaptic terminal
Botulinum
Pretreat with antihistamines and a slow infusion rate
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)


44. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
Ibuprofen - Naproxen - and Indomethacin
- Chlorpromazine - thioridazine - haloperidol
Clavulanic acid
H2 antagonist


45. What are five possible toxic effects of Aspirin therapy?


46. Clinical use of Isoniazid (INH)?
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Digitoxin 168hrs Digoxin 40 hrs
Phosphorylation by a Viral Kinase


47. What are common serious side effects of Aminoglycosides and What are these associated with?
Benzodiazepine.
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
torsade de pointes - excessive Beta block
Chronic gout.


48. The MOA for Chloramphenicol is?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
CMV Retinitis in IC pts When Ganciclovir fails
Inhibition of 50S peptidyl transferase - Bacteriostatic
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)


49. For Warfarin What is the Duration of action
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Chronic (weeks or months)


50. Your patient wants an effective drug to treat his motion sickness - What would you prescribe
fetal renal toxicity - hyperkalemia
Scopolamine
Inhibit viral DNA polymerase
dry mouth - sedation - severe rebound hypertension