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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. Adverse effects of Loop Diuretics?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
CMV Retinitis in IC pts When Ganciclovir fails
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

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

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3. What are the Anti - TB drugs?
Protease Inhibitors and Reverse Transcriptase Inhibitors
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Epinephirine(Alpha1 -2 and Beta 1 -2)

4. What is the clinical use for Nystatin?
1. Weight gain 2. Hepatotoxicity (troglitazone)
Nucleosides
Topical and Oral - for Oral Candidiasis (Thrush)
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.

5. What is the category of drug names ending in - cycline (e.g. Tetracycline)
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
Antibiotic - protein synthesis inhibitor.
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Inhibits Viral DNA polymerase

6. Common toxicities associated with Fluoroquinolones?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
hyperaldosteronism - K+ depletion - CHF
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Systemic mycoses

7. Spironolactone - mechanism?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
competitive inhibirot of aldosterone in the cortical collecting tubule
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
- Glucagon

8. What is the memory key for the effect of magnesium hydroxide overuse?
Mg = Must go to the bathroom.
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Doxycycline - because it is fecally eliminated
- Alkalinize urine & dialysis

9. How is Acyclovir used clinically?
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
- Quinidine - quinine
anuria - CHF
AZT

10. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Hydralazine and Minoxidil
Erectile dysfunction.

11. Acetazolamide causes?

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12. What is Clindamycin used for clinically?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Acetylcholine esterase
- Ethosuxamide - sulfonamides - lamotrigine

13. Which drug(s) cause this reaction: Thrombotic complications?
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
- Oral Contraceptives
distal convoluted tubule (early)
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

14. What organism is Imipenem/cilastatin the Drug of Choice for?
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Leukotrienes increasing bronchial tone.
Enterobacter
Interferes with microtubule function - disrupts mitosis - inhibits growth

15. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
atropine - homatropine - tropicamide
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

16. List the mechanism - clinical use - & toxicity of Methotrexate.
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
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.

17. Is resistant to penicillinase?
Imipenem
TCA
- Haloperidol - chlorpromazine - reserpine - MPTP
Nucleosides

18. Beta Blockers - CV toxicity?
bradycardia - AV block - CHF
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
AV nodal cells
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

19. What conditions are treated with Metronidazole?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Butyrophenone (neuroleptic).
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
AmOxicillin has greater Oral bioavailability

20. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Amphotericin B - Nystatin - Fluconazole/azoles
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Binding to the presynaptic alpha 2 release modulating receptors
Protease inhibitor.

21. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Babiturate.

22. Oral Penicillin
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Penicillin - V
RESPIre

23. Which cancer drugs inhibit nucleotide synthesis(3)?
Dermatophytes (tinea - ringworm)
is resistant
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
- Methotrexate - 5 FU - 6 mercaptopurine

24. Antiarrhythmic class IC- toxicity?
- Penicillamine
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
proarrhythmic

25. Foscarnet does not require activation by a...
viral kinase
INH: Injures Neurons and Hepatocytes
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

26. What is the MOA for Metronidazole?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Forms toxic metabolites in the bacterial cell - Bactericidal
aPTT (intrinsic pathway)
Prophylaxis for Influenza A - Rubella; Parkinson's disease

27. What is combined with Ampicillin - Amoxicillin - Carbenicillin - Piperacillin - and Ticarcillin to enhance their spectrum?
Inhibition of 50S peptidyl transferase - Bacteriostatic
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Clavulanic acid
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

28. How is Amphotericin B administered for fungal meningitis?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Verapamil - Diltiazem - Bepridil
Liver
Intrathecally

29. What are four conditions in Which H2 Blockers are used clinically?
Resistant Gram - infections
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
- Lithium
Rare.

30. Name the common Fluoroquinolones (6)
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Headache - flushing - dyspepsia - blue - green color vision.
Lipoxygenase
Beta - lactam antibiotics

31. Name four Antiarrhythmic drugs in class III.
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Inhibition of 50S peptidyl transferase - Bacteriostatic
Sotalol - Ibutilide - Bretylium - Amiodarone
Systemic mycoses

32. For Heparin What is the Lab value to monitor
Triple sulfas or SMZ
aPTT (intrinsic pathway)
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
- Dimercaprol - succimer

33. What are two Glitazones?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Nifedipine - Verapamil - Diltiazem
1. Pioglitazone 2. Rosiglitazone.
Potent immunosuppressive used in organ transplant recipients.

34. List the specific antidote for this toxin: Methemoglobin
- Methylene blue
Topical and Oral - for Oral Candidiasis (Thrush)
- Physostigmine salicylate
With supplemental Folic Acid

35. What is the MOA of the RT Inhibitors?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
proarrhythmic
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.)
Polymyxin B - Polymyxin E

36. List the specific antidote for this toxin: Acetaminophen
- N- acetylcystine
- Protamine
- B51Naloxone / naltrexone (Narcan)
Long.

37. Antimicrobial prophylaxis for Syphilis
- Steroids - Tamoxifen
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Benzathine penicillin G
Immediate anticoagulation for PE - stroke - angina - MI - DVT.

38. Decrease Digitoxin dose in renal failure?
NO
Foscarnet = pyroFosphate analog
Aminoglycosides
It inhibits release of NE.

39. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Tricyclic antidepressant.

40. What are Polymyxins used for?
Resistant Gram - infections
competitive inhibirot of aldosterone in the cortical collecting tubule
Used in combination therapy with SMZ to sequentially block folate synthesis
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

41. What is the clinical use for Penicillin?
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Prevents the release of ACh - Which results in muscle paralysis.
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Paranteral (IV - SC)

42. Adverse effects of Clonidine?
Succinylcholine
Antibiotic - protein synthesis inhibitor.
dry mouth - sedation - severe rebound hypertension
Aminoglycosides

43. Explain differences between full and partial agonists(2).
- Lithium
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
- Act on same receptor - Full has greater efficacy
- Shifts the curve down - reduces Vmax

44. What are two toxicities of the Glitazones?
No - it inhibits the release of Nor Epi
pulmonary edema - dehydration
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
1. Weight gain 2. Hepatotoxicity (troglitazone)

45. What is used to reverse the action of Heparin?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
proximal convoluted tubule
Ipratropium
1. Pioglitazone 2. Rosiglitazone.

46. What is the formula for Clearance (CL)
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
CL= (rate of elimination of drug/ Plasma drug conc.)
Delirium - Tremor - Nephrotoxicity
- Normalize K+ - Lidocaine - & Anti - dig Mab

47. What is Imipenem always administered with?
Penicillin.
Cilastatin
Hydralazine and Minoxidil
ACE inhibitor.

48. Antiarrhythmic class IV- toxicity?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Increases coumadin metabolism
GI upset - Superinfections - Skin rashes - Headache - Dizziness

49. What is the clinical use for Warfarin?
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.
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
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.
Chronic anticoagulation.

50. Digoxin v. Digitoxin: bioavailability?
sedation - depression - nasal stuffiness - diarrhea
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
fetal renal toxicity - hyperkalemia
Digitoxin>95% Digoxin 75%