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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 is are two clinical uses of Cyclosporine?
Hypersensitivity reactions
- Oxalic acid - Acidosis & nephrotoxicity
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

2. What are common side effects of RT Inhibitors?
- Ethosuxamide - sulfonamides - lamotrigine
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
effective in torsade de pointes and digoxin toxicity

3. List the specific antidote for this toxin: Heparin
- Shifts the curve down - reduces Vmax
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Pseudomonas species and Gram - rods
- Protamine

4. Why is carbachol and pilocarpine useful in treatment of glaucoma?
VACUUM your Bed Room'
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
GI upset - Superinfections - Skin rashes - Headache - Dizziness

5. What is the category of drug names ending in - olol (e.g. Propranolol)
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Aminoglycosides
Beta antagonist.
Polymyxin B - Polymyxin E

6. Antimicrobial prophylaxis for Syphilis
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Benzathine penicillin G
Foscarnet = pyroFosphate analog
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

7. Name some common Sulfonamides (4)
Hypersensitivity reactions
Inhibits CMV DNA polymerase
AZT
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

8. Ethacrynic Acid - clinical use?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
IV vitamin K and fresh frozen plasma
Diuresis in pateints with sulfa allergy
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

9. What is the mechanism of action of Mifepristone (RU486)?
- NaHCO3
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Competitive inibitor of progestins at progesterone receptors.

10. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Severe Gram - rod infections.

11. What Sulfonamides are used for simple UTIs?
Chronic gout.
Triple sulfas or SMZ
physostigmine
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.

12. Which drug(s) cause this reaction: Neuro and Nephrotoxic?
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Alpha -1 antagonist
blocks SR Ca2+ channels
- polymyxins

13. What is combination TMP- SMZ used to treat?
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
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Lipoxygenase

14. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
No - hemicholinum block the uptake of Choline and thus Ach synthesis
block Na+ channels in the cortical collecting tubule
ACIDazolamide' causes acidosis
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

15. What can result due to antacid overuse?
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Digitoxin>95% Digoxin 75%
pulmonary edema - dehydration

16. What is the formula for Clearance (CL)
Captopril - Enalapril - Lisinopril
Carbenicillin - Piperacillin - and Ticarcillin
CL= (rate of elimination of drug/ Plasma drug conc.)
Methylation of rRNA near Erythromycin's ribosome binding site

17. Hydralazine - toxicity?
Ipratropium
GI discomfort
compensatory tachycardia - fluid retention - lupus - like syndrome
Indomethacin is used to close a patent ductus arteriosus.

18. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
- Haloperidol - chlorpromazine - reserpine - MPTP
- Isoniazid
Botulinum
Competitive inibitor of progestins at progesterone receptors.

19. What physiological effects was the Anes using Atropine to tx
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

20. What is the mechanism of Azathioprine?
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Keratin containing tissues - e.g. - nails
Protease inhibitor.

21. What are the four conditions in Which Omeprazole - Lansoprazole is used?
CL= (rate of elimination of drug/ Plasma drug conc.)
thiazides - amiloride
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
- Fluoroquinolones

22. What is the category of drug names ending in - ane (e.g. Halothane)
Inhalational general anesthetic.
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
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.)
Same as penicillin. Extended spectrum antibiotics

23. Digoxin v. Digitoxin: bioavailability?
Competitive inibitor of progestins at progesterone receptors.
Cyclooxygenases (COX I - COX II).
Digitoxin>95% Digoxin 75%
Beta antagonist.

24. Describe first - order kinetics?
Topical and Oral - for Oral Candidiasis (Thrush)
- Normalize K+ - Lidocaine - & Anti - dig Mab
Constant FRACTION eliminated per unit time.(exponential)
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT

25. Which drug(s) cause this reaction: Hepatitis?
cardiac depression - peripheral edema - flushing - dizziness - constipation
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
- Isoniazid

26. List the specific antidote for this toxin: Acetaminophen
compensatory tachycardia - fluid retention - lupus - like syndrome
cardiac depression - peripheral edema - flushing - dizziness - constipation
- N- acetylcystine
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity

27. How is Ganciclovir activated?
severe hypertension - CHF
Phosphorylation by a Viral Kinase
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

28. For Heparin What is the Onset of action
Rapid (seconds)
Indirect agonist - uptake inhibitor
Carbachol - pilocarpine - physostigmine - echothiophate
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

29. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
Due to the presence of a bulkier R group
Oral
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Activates antithrombin III

30. Ethacrynic Acid - mechanism?
not a sulfonamide - but action is the same as furosemide
Premature infants - because they lack UDP- glucuronyl transferase
Pregnant women - Children; because animal studies show Damage to Cartilage
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

31. What are two toxicities associated with Cyclosporine?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Bleeding.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

32. What are the Anti - TB drugs?
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
- Lithium

33. Why does NE result in bradycardia?
Quinidine - Amiodarone - Procainamide - Disopyramide
Erectile dysfunction.
- polymyxins
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

34. Name four Antiarrhythmic drugs in class III.
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Sotalol - Ibutilide - Bretylium - Amiodarone

35. What is the clinical use of Tacrolimus (FK506)?
- Hydralazine - Procainamide - INH - phenytoin
GET on the Metro
Potent immunosuppressive used in organ transplant recipients.
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

36. How are Sulfonamides employed clinically?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Ibuprofen - Naproxen - and Indomethacin
Gram + - Gram - - Norcardia - Chlamydia

37. What class of drug is echothiophate? What is its indication?
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
anticholinesterase glaucoma
Immediate anticoagulation for PE - stroke - angina - MI - DVT.

38. Which drug(s) cause this reaction: Oto and Nephrotoxicity (3)?
Hypersensitivity reactions
- aminoglycosides - loop diuretics - cisplatin
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)

39. What is action of insulin in the liver - in muscle - and in adipose tissue?
Cephalosporins
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

40. What is the mechanism of action of Sildenafil (Viagra)?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Intrathecally
- Vitamin K & fresh frozen plasma

41. How is Amphotericin B used clinically?
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

42. Acetazolamide causes?

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43. Verapamil has similar action to?
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
proarrhythmic
Beta Blockers

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

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45. Name three Antiarrhythmic drugs in class IC.
- Tamoxifen
Flecainide - Encainide - Propafenone
The PT.
NO

46. What is the mechanism of action of Misoprostol?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Foscarnet = pyroFosphate analog

47. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- Quinidine - quinine
Disulfiram - like reaction with EtOH - Headache

48. What is Ketoconazole specifically used for?
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Hypersensitivity reactions

49. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
cyanide toxicity (releases CN)
all of them
AZT

50. What are toxic side effects for Metronidazole?
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Nucleosides
Disulfiram - like reaction with EtOH - Headache