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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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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. Which diuretics increase urine Ca2+?
effective in torsade de pointes and digoxin toxicity
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Beta1 more than B2
loop diuretics - spironolactone

2. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
Due to the presence of a bulkier R group
Pralidoxime regenerates active cholinesterase.
Gemfibrozil - Clofibrate
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased

3. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
Increase target cell response to insulin.
AZT
- Tetracycline
- Bleomycin - amiodarone - busulfan

4. What is the specific clinical use of Indomethacin in neonates?
Indomethacin is used to close a patent ductus arteriosus.
Resistant Gram - infections
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Imipenem

5. What organism is Imipenem/cilastatin the Drug of Choice for?
- Nitrate - hydroxocobalamin thiosulfate
VACUUM your Bed Room'
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Enterobacter

6. How would hemicholinium treatment affect cholinergic neurons?
Pralidoxime regenerates active cholinesterase.
- Ethosuxamide - sulfonamides - lamotrigine
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Erythromycin - Azithromycin - Clarithromycin

7. MOA for Penicillin (3 answers)?
Antibiotic - protein synthesis inhibitor.
Inhibt Assembly of new virus by Blocking Protease Enzyme
The PT.
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes

8. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Antifungal.
Succinylcholine
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Doxycycline - because it is fecally eliminated

9. What is an occasional side effect of Aztreonam?
GI upset
Hypersensitivity reactions
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
- Nitrate - hydroxocobalamin thiosulfate

10. How does angiotensin II affect NE release?
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
GI upset - Superinfections - Skin rashes - Headache - Dizziness
It acts presynaptically to increase NE release.

11. How is Ribavirin used clinically?
for RSV
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
- Aminocaproic acid

12. Antimicrobial prophylaxis for Gonorrhea
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
It must be Phosphorylated by Viral Thymidine Kinase
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Ceftriaxone

13. For Heparin What is the Onset of action
No
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Rapid (seconds)
- Shifts the curve down - reduces Vmax

14. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
Phenothiazine (neuroleptic - antiemetic).
ACE inhibitor.
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
hyperaldosteronism - K+ depletion - CHF

15. What is the clinical use for Ampicillin and Amoxicillin?
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
Short.
Prevents the release of ACh - Which results in muscle paralysis.

16. List the mechanism - clinical use - & toxicity of Etoposide.
Premature infants - because they lack UDP- glucuronyl transferase
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
proximal convoluted tubule - thin descending limb - and collecting duct
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.

17. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
Acetylcholinesterase; ACh is broken down into choline and acetate.
effective in torsade de pointes and digoxin toxicity
Chronic gout.
Because they require some residual islet function.

18. What is the MOA of the RT Inhibitors?
Antileukotriene; blocks leukotriene receptors.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
loop diuretics - spironolactone
Bleeding.

19. What are the clinical uses for Ticlopidine - Clopidogrel?
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
- Shifts the curve down - reduces Vmax

20. Explain potency in relation to full and partial agonists(2).
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
- Penicillin
- Shifts the curve down - reduces Vmax
Disulfiram - like reaction with EtOH - Headache

21. What is an additional side effect of Methicillin?
Only in limited amounts
RESPIre
Interstitial nephritis
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity

22. What is the memory key for Metronidazole's clinical uses?
Premature infants - because they lack UDP- glucuronyl transferase
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Polymyxin B - Polymyxin E
GET on the Metro

23. These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
Amphetamine and Ephedrine
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
For serious - Gram + multidrug - resistant organisms
Penicillin - V

24. List the specific antidote for this toxin: TPA & Streptokinase
- Aminocaproic acid
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Beta1 more than B2

25. Which drug(s) cause this reaction: Cough?
- ACE inhibitors (Losartan>no cough)
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Rare.
GI side effects. (Indomethacin is less toxic - more commonly used.)

26. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Lipoxygenase
Tricyclic antidepressant.
No - it inhibits the release of Nor Epi
Hypersensitivity reactions

27. Bretyllium - toxicity?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Benzodiazepine.
Pituitary hormone.
new arrhythmias - hypotension

28. Ryanodine - site of action?
blocks SR Ca2+ channels
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Phenothiazine (neuroleptic - antiemetic).
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

29. List the specific antidote for this toxin: Opioids
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
- Corticosteroids - heparin
- B51Naloxone / naltrexone (Narcan)
Inhibit Ergosterol synthesis

30. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
troponin - tropomyosin system
H2 antagonist
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

31. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
Chronic anticoagulation.
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Dermatophytes (tinea - ringworm)
Penicillin.

32. Which RT inhibitors cause a Rash?
Inhibits reabsorption of uric acid.
troponin - tropomyosin system
Non - Nucleosides
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

33. Hydralazine - class and mechanism?
Scopolamine
reversible SLE- like syndrome
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

34. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
sedation - sleep alterations
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

35. A group of pts are rushed into the ER complaining of excessive sweating - tearing - salivation - HA - N and V - muscle twitching - difficulty breathing and diarrhea. What drug would be the most effective immediate tx
Rare.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
They inhibit reuptake of NE at the nerve terminal (as does cocaine).

36. What cholinergic inhibitor acts by directly inhibiting Ach release at the presynaptic terminal
Beta - lactamase cleavage of Beta - lactam ring
- Tamoxifen
Botulinum
edrophonium (extremely short acting anticholinesterase)

37. Antiarrhythmic class IB- toxicity?
GI disturbances.
Antileukotriene; blocks synthesis by lipoxygenase.
local anesthetic. CNS stimulation or depression. CV depression.
physostigmine

38. Adverse effects of Prazosin?
edrophonium (extremely short acting anticholinesterase)
first dose orthostatic hypotension - dizziness - headache
Constant FRACTION eliminated per unit time.(exponential)
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)

39. How is Griseofulvin used clinically?
1. Antiandrogen 2. Nausea 3. Vomiting
Chronic anticoagulation.
Oral treatment of superficial infections
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

40. What is the mechanism of action of Cyclosporine?
- Deferoxamine
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
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.
GI discomfort

41. Ethacrynic Acid - toxicity?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Cyclooxygenases (COX I - COX II).
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

42. Which diuretics cause acidosis?
Pyridoxine (B6) administration
cardiac muscle: Verapamil>Diltiazem>Nifedipine
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
carbonic anhydrase inhibitors - K+ sparing diuretics

43. What is a mnemonic to remember Amantadine's function?
Blocks Influenza A and RubellA; causes problems with the cerebellA
Pregnant women - Children; because animal studies show Damage to Cartilage
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Staphlococcus aureus

44. Digoxin v. Digitoxin: protein binding?
- aminoglycosides - loop diuretics - cisplatin
Pituitary hormone.
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Digitoxin 70% Digoxin 20-40%

45. Name some common Tetracyclines (4)
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Tetracycline - Doxycycline - Demeclocycline - Minocycline
ACE inhibitor.

46. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

47. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
- Methotrexate - 5 FU - 6 mercaptopurine
AZT - to reduce risk of Fetal Transmission

48. Which drug(s) cause this reaction: Gingival hyperplasia?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
- Phenytoin
for RSV
GI side effects. (Indomethacin is less toxic - more commonly used.)

49. Amiodarone - toxicity?
Lipoxygenase
cross - allergenic
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.

50. List the specific antidote for this toxin: Acetaminophen
Ipratropium
Increase target cell response to insulin.
- Methotrexate - 5 FU - 6 mercaptopurine
- N- acetylcystine