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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 of Griseofulvin?
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Interferes with microtubule function - disrupts mitosis - inhibits growth
- Fluoroquinolones
Onchocerciasis ('river blindness'-- rIVER- mectin)

2. What is the definition of zero - order kinetics? Example?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Beta - lactam antibiotics
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

3. What microorganisms are Aminoglycosides ineffective against?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Cell membrane Ca2+ channels of cardiac sarcomere
Anaerobes

4. What are the clinical uses for Aztreonam?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Rash - Pseudomembranous colitis

5. What is the mechanism of action of Cyclosporine?
Stimulates beta adrenergic receptors
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.
Blood
reversible SLE- like syndrome

6. In coma situations you rule out What (7)?

7. What physiological effects was the Anes using Atropine to tx
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
- Aminocaproic acid
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Chronic anticoagulation.

8. What antimuscarinic agent is used in asthma and COPD?
Polymyxins
Ipratropium
Pregnant women - Children; because animal studies show Damage to Cartilage
Blocks Norepi - but not Dopamine

9. What drug is given for Pneumocystis carinii prophylaxis?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Pentamidine
Norepinephrine

10. Which drug(s) cause this reaction: Neuro and Nephrotoxic?
- polymyxins
Keratin containing tissues - e.g. - nails
- Lithium
Inhibit viral DNA polymerase

11. What is the clinical use for Sucralfate?
With supplemental Folic Acid
Heparin catalyzes the activation of antithrombin III.
Peptic ulcer disease.
- Phenytoin

12. Does Ampicillin or Amoxicillin have a greater oral bioavailability?
AmOxicillin has greater Oral bioavailability
Blocks Norepi - but not Dopamine
Nifedipine - Verapamil - Diltiazem
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)

13. Name two bile acid resins.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
cholestyramine - colestipol
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Cephalosporins

14. What are three possible complications of Heparin therapy?
Quinidine - Amiodarone - Procainamide - Disopyramide
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

15. List the specific antidote for this toxin: Beta Blockers
Diuresis in pateints with sulfa allergy
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
- Glucagon
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)

16. How is Ribavirin used clinically?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
for RSV
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.

17. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
Antileukotriene; blocks leukotriene receptors.
Due to the presence of a bulkier R group
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Pseudomonas species and Gram - rods

18. List the specific antidote for this toxin: Arsenic (all heavy metals)
Rash - Pseudomembranous colitis
- Dimercaprol - succimer
VACUUM your Bed Room'
Antifungal.

19. What is the category of drug names ending in - caine (e.g. Lidocaine)
Local anesthetic.
hypertension - angina - arrhythmias
Succinylcholine
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

20. Adverse effects of Methyldopa?

21. Cautions When using Amiodarone?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
check PFTs - LFTs - and TFTs
Impairs the synthesis of vitamin K- dependent clotting factors

22. Name common Polymyxins
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Butyrophenone (neuroleptic).
Hydralazine and Minoxidil
Polymyxin B - Polymyxin E

23. Describe first - order kinetics?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Constant FRACTION eliminated per unit time.(exponential)
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Nephrotoxicity

24. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Penicillin.
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
With an amino acid change of D- ala D- ala to D- ala D- lac

25. What are Amantadine - associated side effects?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Ataxia - Dizziness - Slurred speech
first dose orthostatic hypotension - dizziness - headache
Na/K ATPase

26. What is a common side effect of Misoprostol?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Diarrhea
severe hypertension - CHF
Increase target cell response to insulin.

27. What is the mechanism of action of NSAIDs other than Aspirin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Long.
Modification via Acetylation
Oral

28. For Warfarin What is the Route of administration
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
viral kinase
reversible SLE- like syndrome
Oral

29. Name four Antiarrhythmic drugs in class III.
decrease conduction velocity - increase ERP - increase PR interval
Sotalol - Ibutilide - Bretylium - Amiodarone
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Scopolamine

30. What are Aminoglycosides used for clinically?
Alpha -1 antagonist
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Severe Gram - rod infections.
Blocks Influenza A and RubellA; causes problems with the cerebellA

31. What is combination TMP- SMZ used to treat?
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT

32. Explain pH dependent urinary drug elimination?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
- Flumazenil
Antileukotriene; blocks leukotriene receptors.

33. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
Same as penicillin. Extended spectrum antibiotics
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Pyridoxine (B6) administration
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)

34. What are the clinical indications for neostigmine?
GI discomfort
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Forms toxic metabolites in the bacterial cell - Bactericidal

35. What is the category of drug names ending in - ane (e.g. Halothane)
Inhalational general anesthetic.
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

36. What is Nifurtimox administered for?

37. How does a competitive antagonist effect an agonist?
Protease Inhibitors and Reverse Transcriptase Inhibitors
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
- Shifts the curve to the right - increases Km
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

38. What are common side effects of RT Inhibitors?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
BM suppression (neutropenia - anemia) - Peripheral neuropathy
- Act on same receptor - Full has greater efficacy
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

39. Resistance mechanisms for Chloramphenicol
troponin - tropomyosin system
- Bleomycin - amiodarone - busulfan
Modification via Acetylation
- Ethanol - dialysis - & fomepizole

40. Which drug(s) cause this reaction: SLE- like syndrome?
- Hydralazine - Procainamide - INH - phenytoin
Mg = Must go to the bathroom.
It must be Phosphorylated by Viral Thymidine Kinase
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

41. Which cancer drugs effect nuclear DNA (4)?
Penicillin - G
Topical and Oral - for Oral Candidiasis (Thrush)
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Albuterol - tertbutaline

42. What organisms does Griseofulvin target?
- aminoglycosides - loop diuretics - cisplatin
- Glucocorticoid withdrawal
Dermatophytes (tinea - ringworm)
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

43. What parasitic condition is treated with Ivermectin?

44. Name the steps in drug approval(4)?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
For serious - Gram + multidrug - resistant organisms
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

45. Which RT inhibitors cause Lactic Acidosis?
GnRH analog with agonist properties When used in pulsatile fashion and antagonist properties When used in continuous fashion - causing a transient initial burst of LH and FSH
Nucleosides
Succinylcholine
Botulinum

46. Which drug(s) cause this reaction: P450 induction(6)?
Chronic gout.
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Early myocardial infarction.
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

47. What is the memory key involving the '4 R's of Rifampin?'
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Methylation of rRNA near Erythromycin's ribosome binding site
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
GI discomfort

48. What is the MOA for the Tetracyclines?
- Ammonium Chloride
NO
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

49. What are the clinical uses for Ticlopidine - Clopidogrel?
Reversible block of histamine H2 receptors
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
GI distress - Skin rash - and Seizures at high plasma levels

50. IV Penicillin
Phenothiazine (neuroleptic - antiemetic).
Digitoxin 70% Digoxin 20-40%
Penicillin - G
Pseudomonas species and Gram - rods