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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. What is the MOA for the Tetracyclines?
Inhalational general anesthetic.
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

2. What is treated with Chloroquine - Quinine - Mefloquine?
Antibiotic - protein synthesis inhibitor.
Triple sulfas or SMZ
distal convoluted tubule (early)
Malaria (P. falciparum)

3. What effect would atropine have on the preganglionic sympathetic activation of sweat glands? Would this person sweat?
Chronic gout.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
- polymyxins

4. How is Trimethoprim used clinically?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Only in limited amounts
Used in combination therapy with SMZ to sequentially block folate synthesis
Inhalational general anesthetic.

5. What are three toxicities of Leuprolied?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
-100% oxygen - hyperbaric
hypertension - CHF - diabetic renal disease
1. Antiandrogen 2. Nausea 3. Vomiting

6. Spironolactone - mechanism?
Heparin catalyzes the activation of antithrombin III.
competitive inhibirot of aldosterone in the cortical collecting tubule
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

7. Name three Antiarrhythmic drugs in class IV.
- Tamoxifen
Verapamil - Diltiazem - Bepridil
check PFTs - LFTs - and TFTs
Pregnant women - Children; because animal studies show Damage to Cartilage

8. What is the category of drug names ending in - cycline (e.g. Tetracycline)
RESPIre
Modification via Acetylation - Adenylation - or Phosphorylation
Decreases synthesis of Mycolic Acid
Antibiotic - protein synthesis inhibitor.

9. What cholinomimetic is useful in the diagnosis of Myasthenia Gravis
loop diuretics - thiazides
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Edrophonium
Early myocardial infarction.

10. What microorganisms are Aminoglycosides ineffective against?
Epinephirine(Alpha1 -2 and Beta 1 -2)
Anaerobes
toxic
INH: Injures Neurons and Hepatocytes

11. What reversal agent could a Anes give to reverse the effects of Atropine
Aminoglycosides
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Bethanechol - Neostigmine - physostigmine
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.

12. List the specific antidote for this toxin: Salicylates
Cephalosporins
- Alkalate DNA - Brain tumors - CNS toxicity
- Alkalinize urine & dialysis
for RSV

13. What anticholinesterase crosses the blood - brain - barrier?
physostigmine
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.
It affects beta receptors equally and is used in AV heart block (rare).
Foscarnet = pyroFosphate analog

14. Isopoterenol was given to a patient with a developing AV block - why?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Indirect agonist - uptake inhibitor
Penicillin - V
Stimulates beta adrenergic receptors

15. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
- Act on same receptor - Full has greater efficacy
Botulinum
Praziquantel

16. What are common toxicities associated with Macrolides? (4)
for RSV
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

17. What is the major side effect for Ampicillin and Amoxicillin?
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
No - it inhibits the release of Nor Epi
Hypersensitivity reactions
Cyclooxygenases (COX I - COX II).

18. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
for RSV
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.)
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

19. Which drug(s) cause this reaction: SLE- like syndrome?
propanolol - esmolol - metoprolol - atenolol - timolol
- Deferoxamine
- Hydralazine - Procainamide - INH - phenytoin
Used in combination therapy with SMZ to sequentially block folate synthesis

20. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
VACUUM your Bed Room'
Those patients who are taking nitrates.
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility

21. Which drug(s) cause this reaction: P450 inhibition(6)?
Acetylcholine esterase
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
TMP- SMZ (DOC) - aerosolized pentamidine
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

22. Toxic effects of TMP include?
- Hydralazine - Procainamide - INH - phenytoin
Megaloblastic anemia - Leukopenia - Granulocytopenia
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

23. Name two bile acid resins.
Inhibit Ergosterol synthesis
Indirect agonist - uptake inhibitor
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
cholestyramine - colestipol

24. Which cancer drugs effect nuclear DNA (4)?
not a sulfonamide - but action is the same as furosemide
effective in torsade de pointes and digoxin toxicity
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Primaquine

25. What is the mechanism of action of Mifepristone (RU486)?
Competitive inibitor of progestins at progesterone receptors.
cortical collecting tubule
Dermatophytes (tinea - ringworm)
Succinylcholine

26. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
Megaloblastic anemia - Leukopenia - Granulocytopenia
Norepinephrine (Alpha1 -2 and beta 1)
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

27. Toxic side effects of the Azoles?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
- Isoniazid

28. Which drug(s) cause this reaction: Tardive dyskinesia?
Choline acetyltransferase
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)
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- Antipsychotics

29. Ibutilide - toxicity?
torsade de pointes
edrophonium (extremely short acting anticholinesterase)
sedation - sleep alterations
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

30. What is are two clinical uses of Cyclosporine?
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
troponin - tropomyosin system
Sulfonamides - Trimethoprim

31. The MOA for Chloramphenicol is?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Inhibition of 50S peptidyl transferase - Bacteriostatic
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Aplastic anemia (dose independent) - Gray Baby Syndrome

32. Hydralazine - class and mechanism?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
- Normalize K+ - Lidocaine - & Anti - dig Mab
- Alkalinize urine & dialysis
Pituitary hormone.

33. What are two Glitazones?
Epinephirine(Alpha1 -2 and Beta 1 -2)
Ipratropium
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
1. Pioglitazone 2. Rosiglitazone.

34. What do you treat Nematode/roundworm (pinworm - whipworm) infections with?
Mebendazole/Thiabendazole - Pyrantel Pamoate
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
RESPIre

35. Explain potency in relation to full and partial agonists(2).
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
- Chloramphenicol
Diarrhea
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

36. Describe the MOA of Interferons (INF)
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Inhibits Viral DNA polymerase

37. What are the clinical uses for Aztreonam?
Tendonitis and Tendon rupture
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Captopril - Enalapril - Lisinopril

38. Which RT inhibitor causes Megaloblastic Anemia?
Cell membrane Ca2+ channels of cardiac sarcomere
edrophonium (extremely short acting anticholinesterase)
AZT
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

39. What are the Macrolides used for clinically?
Rifampin
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Delirium - Tremor - Nephrotoxicity

40. Preferential action of the Ca2+ channel blockers at cardiac muscle?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
cardiac muscle: Verapamil>Diltiazem>Nifedipine
decrease

41. What is the mechanism of action of the H2 Blockers?
Reversible block of histamine H2 receptors
pulmonary edema - dehydration
check PFTs - LFTs - and TFTs
AZT - to reduce risk of Fetal Transmission

42. List the mechanism - clinical use - & toxicity of Paclitaxel.
Hypersensitivity reactions
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Impairs the synthesis of vitamin K- dependent clotting factors

43. Why does NE result in bradycardia?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

44. MOA: Bactericidal antibiotics
Abortifacient.
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Small lipid - soluble molecule
PT

45. How are the HIV drugs used clinically?

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46. What microorganisms are clinical indications for Tetracycline therapy?

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47. How does NE modulate its own release? What other neurotransmitter has this same effect?
Dopamine
Beta1 more than B2
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

48. For Warfarin What is the Structure
Potent immunosuppressive used in organ transplant recipients.
Oxygen
Small lipid - soluble molecule
Peptic ulcer disease.

49. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Suramin
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Choline acetyltransferase

50. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
- Fluoroquinolones
Pseudomonas species and Gram - rods
Binding to the presynaptic alpha 2 release modulating receptors
Hydralazine and Minoxidil