USMLE Step 1 Pharmacology

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 MOA of Ganciclovir?
Inhibits CMV DNA polymerase
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
- Shifts the curve down - reduces Vmax
Oxygen


2. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
Modification via Acetylation
1. Reliable (<1% failure) 2. Lowers risk of endometrial and ovarian cancer 3. Decreased incidence of ectopic pregnancy 4. Lower risk of pelvic infections 5. Regulation of menses
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
TCA


3. Aztreonam is not ________ with penicillins
proximal convoluted tubule - thin descending limb - and collecting duct
cross - allergenic
Local anesthetic.
Headache - flushing - dyspepsia - blue - green color vision.


4. What populations are Floroquinolones contraindicated in? Why?
dry mouth - sedation - severe rebound hypertension
Carbenicillin - Piperacillin - and Ticarcillin
Rare.
Pregnant women - Children; because animal studies show Damage to Cartilage


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

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6. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Potent immunosuppressive used in organ transplant recipients.
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Tricyclic antidepressant.
Pentamidine


7. How is Amantadine used clinically?

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8. Triamterene and amiloride - mechanism?
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.
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
block Na+ channels in the cortical collecting tubule
- Cloazapine - carbamazapine - colchicine - PTU


9. What is the mechanism of action of NSAIDs other than Aspirin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- Methotrexate - 5 FU - 6 mercaptopurine
- Physostigmine salicylate
blocks SR Ca2+ channels


10. What is the mechanism of action of Colchicine used to treat acute gout?
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
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.
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.


11. What musculo - skeletal side effects in Adults are associated with Floroquinolones?
Tendonitis and Tendon rupture
It affects beta receptors equally and is used in AV heart block (rare).
Pretreat with antihistamines and a slow infusion rate
- Oxalic acid - Acidosis & nephrotoxicity


12. What is the category of drug names ending in - cycline (e.g. Tetracycline)
It acts presynaptically to increase NE release.
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Antibiotic - protein synthesis inhibitor.


13. Specifically - How does Foscarnet inhibit viral DNA pol?
Binds to the Pyrophosphate Binding Site of the enzyme
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
H2 antagonist
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate


14. What is the main clinical use for the thrombolytics?
Early myocardial infarction.
Botulinum
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)


15. What antimuscarinic agent is used in asthma and COPD?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Ipratropium
Chronic Hepatitis A and B - Kaposi's Sarcoma
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic


16. Antiarrhythmic class IA effects?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
loop diuretics - thiazides


17. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
GI upset
Peptic ulcer disease.
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.)
Praziquantel


18. What is the category of drug names ending in - cillin (e.g. Methicillin)
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Penicillin.
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness


19. Why is Cilastatin administered with Imipenem?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
hypertension - angina - arrhythmias
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.


20. What is the MOA of Foscarnet?
Chronic anticoagulation.
Beta - lactam antibiotics
Inhibits Viral DNA polymerase
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.


21. What is the MOA for Rifampin?
block Na+ channels in the cortical collecting tubule
Useful in muscle paralysis during surgery or mechanical ventilation.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Inhibits DNA dependent RNA polymerase


22. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
- Chloramphenicol
Protease inhibitor.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
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.


23. List the specific antidote for this toxin: Beta Blockers
pulmonary edema - dehydration
- Glucagon
thick ascending limb
- Disulfram & also sulfonylureas - metronidazole


24. List the specific antidote for this toxin: Iron
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.
- Deferoxamine
Large anionic polymer - acidic
distal convoluted tubule (early)


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

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26. Antiarrhythmic class IB- toxicity?
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
local anesthetic. CNS stimulation or depression. CV depression.
Alpha -1 antagonist


27. What are the side effects of Rifampin?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Minor hepatotoxicity - Drug interactions (activates P450)
Scopolamine
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.


28. Mannitol - toxicity?
pulmonary edema - dehydration
torsade de pointes
Inhibits cell wall mucopeptide formation - Bactericidal
Premature infants - because they lack UDP- glucuronyl transferase


29. List the specific antidote for this toxin: TPA & Streptokinase
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
- Aminocaproic acid
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
- Bleomycin - amiodarone - busulfan


30. Beta Blockers - BP?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
bradycardia - AV block - CHF
Paranteral (IV - SC)
decrease


31. K+ sparing diuretics - toxicity?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Beta Blockers
- N- acetylcystine


32. What are Fluoroquinolones indicated for? (3)
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
GI disturbances.
bradycardia - AV block - CHF
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity


33. Antiarrhythmic class IV- clinical use?
The PT.
prevention of nodal arrhythmias (SVT)
competitive inhibirot of aldosterone in the cortical collecting tubule
Hypersensitivity reactions


34. Your patient wants an effective drug to treat his motion sickness - What would you prescribe
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Scopolamine
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
AmOxicillin has greater Oral bioavailability


35. What is treated with Chloroquine - Quinine - Mefloquine?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
check PFTs - LFTs - and TFTs
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)
Malaria (P. falciparum)


36. Which drug(s) cause this reaction: G6PD hemolysis(8)?
Interstitial nephritis
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
loop diuretics - thiazides
Pregnant women - Children; because animal studies show Damage to Cartilage


37. What is the clinical use of Mifepristone (RU486)?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Abortifacient.
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
torsade de pointes


38. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Same as penicillin. Extended spectrum antibiotics
- Disulfram & also sulfonylureas - metronidazole
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
viral kinase


39. Ibutilide - toxicity?
torsade de pointes
Acetylcholinesterase; ACh is broken down into choline and acetate.
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
The PTT.


40. What are toxic side effects for Metronidazole?
Disulfiram - like reaction with EtOH - Headache
- polymyxins
Stimulates beta adrenergic receptors
Those patients who are taking nitrates.


41. Why does NE result in bradycardia?
Binds to the Pyrophosphate Binding Site of the enzyme
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Penicillin - G
distal convoluted tubule (early)


42. List the specific antidote for this toxin: Anticholinesterases (organophosphate.)
amphetamine and ephedrine
Nevirapine - Delavirdine
- Atropine & pralidoxime
Cardiac glycoside (inotropic agent).


43. What is the MOA for the Tetracyclines?
compensatory tachycardia - fluid retention - lupus - like syndrome
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Enterobacter
GI discomfort


44. What microorganisms are clinical indications for Tetracycline therapy?

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45. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Pseudomonas species and Gram - rods
Malaria (P. falciparum)
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.)


46. Cautions When using Amiodarone?
check PFTs - LFTs - and TFTs
BM suppression (neutropenia - anemia) - Peripheral neuropathy
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Fast vs. Slow Acetylators


47. What is the major side effect for Ampicillin and Amoxicillin?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Succinylcholine
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Hypersensitivity reactions


48. How are the HIV drugs used clinically?

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49. What are three common NSAIDS other than Aspirin?
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
Tendonitis and Tendon rupture
AZT - to reduce risk of Fetal Transmission
Ibuprofen - Naproxen - and Indomethacin


50. Isopoterenol was given to a patient with a developing AV block - why?
Nifedipine - Verapamil - Diltiazem
Ca2+ (Loops Lose calcium)
proarrhythmic
Stimulates beta adrenergic receptors