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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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1. What are are the Sulfonylureas (general description) and What is their use?
Aplastic anemia (dose independent) - Gray Baby Syndrome
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

2. Reserpine will block the syntheis of this drug and but not its precursor.
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
For serious - Gram + multidrug - resistant organisms
Beta antagonist.
Blocks Norepi - but not Dopamine

3. For Heparin What is the Site of action
Blood
Interstitial nephritis
-100% oxygen - hyperbaric
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

4. Cautions When using Amiodarone?
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
check PFTs - LFTs - and TFTs
Nucleosides
Tetracycline - Doxycycline - Demeclocycline - Minocycline

5. What are the four conditions in Which Omeprazole - Lansoprazole is used?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Hypersensitivity reactions
Same as penicillin. Extended spectrum antibiotics
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

6. Resistance mechanisms for Cephalosporins/Penicillins
Beta - lactamase cleavage of Beta - lactam ring
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
Ca2+ (Loops Lose calcium)
Interferes with microtubule function - disrupts mitosis - inhibits growth

7. Which diuretics increase urine Ca2+?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Botulinum
loop diuretics - spironolactone

8. MOA: Block mRNA synthesis
Gram + and Anerobes
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Rifampin
proximal convoluted tubule

9. Name common Polymyxins
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Same as penicillin. Act as narrow spectrum antibiotics
Polymyxin B - Polymyxin E
Chronic gout.

10. Which cancer drugs effect nuclear DNA (4)?
- Antipsychotics
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Tetracycline - Doxycycline - Demeclocycline - Minocycline

11. What are four advantages of newer low - molecular - weight heparins (Enoxaparin)?
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
1. Pioglitazone 2. Rosiglitazone.
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
first dose orthostatic hypotension - dizziness - headache

12. How are Interferons (INF) used clinically?

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13. What can result due to antacid overuse?
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Nitrates
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.

14. List the mechanism - clinical use - & toxicity of 6 MP.
Inhibition of 50S peptidyl transferase - Bacteriostatic
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Foscarnet = pyroFosphate analog
- inhibits HGPRT (pur. Syn.) - Luk - Lymph

15. What is the major toxic side effect of Penicillin?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Hypersensitivity reactions
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.
The PT.

16. What is a mnemonic to remember Amantadine's function?
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.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Pseudomonas species and Gram - rods
Binds to the Pyrophosphate Binding Site of the enzyme

17. Ryanodine - site of action?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
prevention of nodal arrhythmias (SVT)
scopolamine
blocks SR Ca2+ channels

18. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Nifedipine - Verapamil - Diltiazem

19. Adverse effects of Nifedipine - verapamil?
Oral
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
dizziness - flushing - constipation (verapamil) - nausea
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

20. Name three calcium channel blockers?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
1. Pioglitazone 2. Rosiglitazone.
Nifedipine - Verapamil - Diltiazem
Dopamine; causes its release from intact nerve terminals

21. What is the memory key involving the '4 R's of Rifampin?'
CMV - esp in Immunocompromised patients
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
- Methotrexate - 5 FU - 6 mercaptopurine

22. MOA: Block protein synthesis at 50s subunit
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
Pretreat with antihistamines and a slow infusion rate
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
local anesthetic. CNS stimulation or depression. CV depression.

23. What is an additional side effect of Methicillin?
It inhibits release of NE.
very short acting
Interstitial nephritis
troponin - tropomyosin system

24. How is Amphotericin B administered for fungal meningitis?
Intrathecally
Paranteral (IV - SC)
HTN - CHF - calcium stone formation - nephrogenic DI.
Minor hepatotoxicity - Drug interactions (activates P450)

25. What is the mechanism of action of Acetaminophen?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Choline acetyltransferase

26. What is the MOA of Imipenem?
- Act on same receptor - Full has greater efficacy
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
sedation - positive Coombs' test
Acts as a wide spectrum carbapenem

27. For Heparin What is the Mechanism of action
- Ammonium Chloride
dizziness - flushing - constipation (verapamil) - nausea
Activates antithrombin III
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

28. Clinical use of Isoniazid (INH)?
Norepinephrine
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
Neomycin
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB

29. Which drug(s) cause this reaction: Osteoporosis (2)?
severe hypertension - CHF
- Corticosteroids - heparin
- Atropine & pralidoxime
Alpha -1 antagonist

30. How would you treat African Trypanosomiasis (sleeping sickness)?
Protease Inhibitors and Reverse Transcriptase Inhibitors
Suramin
AmOxicillin has greater Oral bioavailability
Methicillin - Nafcillin - and Dicloxacillin

31. What is the mechanism of action of Ticlopidine - Clopidogrel
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
viral kinase
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Penicillin - V

32. What is Metronidazole combined with for 'triple therapy'? Against What organism?
Acute gout.
CMV Retinitis in IC pts When Ganciclovir fails
Yes
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

33. How would hemicholinium treatment affect cholinergic neurons?
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.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Dopamine

34. Adverse effects of Clonidine?
is resistant
dry mouth - sedation - severe rebound hypertension
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
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.

35. What are the clinical uses for Aztreonam?
Primaquine
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

36. Why would you use pralidoxime after exposure to an organophosphate?
It inhibits release of NE.
Pralidoxime regenerates active cholinesterase.
Triple sulfas or SMZ
Increases coumadin metabolism

37. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Same as penicillin. Extended spectrum antibiotics
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Abortifacient.

38. Common toxicities associated with Fluoroquinolones?
Babiturate.
Amphotericin B - Nystatin - Fluconazole/azoles
Penicillin - V
GI upset - Superinfections - Skin rashes - Headache - Dizziness

39. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
Inhibits cell wall mucopeptide formation - Bactericidal
Beta lactams - inhibit cell wall synthesis - Bactericidal
Pretreat with antihistamines and a slow infusion rate
- Protamine

40. These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
Severe Gram - rod infections.
Cyclooxygenases (COX I - COX II).
Amphetamine and Ephedrine
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased

41. What are four conditions in Which H2 Blockers are used clinically?
Nevirapine - Delavirdine
Pseudomonas species and Gram - rods
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Nucleosides

42. For Heparin What is the Lab value to monitor
Ca2+ (Loops Lose calcium)
aPTT (intrinsic pathway)
Cell membrane Ca2+ channels of cardiac sarcomere
viral kinase

43. Ibutilide - toxicity?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
torsade de pointes
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Amphotericin B - Nystatin - Fluconazole/azoles

44. Antiarrhythmic Class III- effects?
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
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
No - warfarin - unlike heparin - can cross the placenta.

45. What is the mechanism of action of the Alpha - glucosidase inhibitors?
propanolol - esmolol - metoprolol - atenolol - timolol
Sildenafil fills the penis
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
VACUUM your Bed Room'

46. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
not a sulfonamide - but action is the same as furosemide
Dopamine
Inhibits Viral DNA polymerase
penicillinase resistant

47. What are four clinical uses of glucocorticoids?

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48. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Stimulates beta adrenergic receptors
Dopamine

49. Thiazides - site of action?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- Vitamin K & fresh frozen plasma
distal convoluted tubule (early)
Digoxin=urinary Digitoxin=biliary

50. What is the mecanism of action - effective period - and ineffective period of use for Cromolyn in treating Asthma?
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Early myocardial infarction.
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity