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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. Guanethidine enhances the release of Norepi?
No - it inhibits the release of Nor Epi
Intrathecally
dry mouth - sedation - severe rebound hypertension
- Isoniazid

2. What is the category - desired effect - and possible mechanism of Theophylline in treating Asthma?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
dry mouth - sedation - severe rebound hypertension
hypertension - angina - arrhythmias

3. List the mechanism - clinical use - & toxicity of Bleomycin.
For serious - Gram + multidrug - resistant organisms
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Praziquantel

4. What is the mechanism of Leuprolide?
Interferes with microtubule function - disrupts mitosis - inhibits growth
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
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
Inhalational general anesthetic.

5. Adverse effects of Hydrochlorothiazide?
Albuterol - tertbutaline
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Digoxin=urinary Digitoxin=biliary

6. Ethacrynic Acid - mechanism?
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
not a sulfonamide - but action is the same as furosemide
- Ethanol - dialysis - & fomepizole
depresses ectopic pacemakers - especially in digoxin toxicity

7. Which drug(s) cause this reaction: Gingival hyperplasia?
- Phenytoin
Ataxia - Dizziness - Slurred speech
Because they require some residual islet function.
Bacitracin - Vancomycin

8. Are penicillinase resistant
Methicillin - Nafcillin - and Dicloxacillin
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Yes
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)

9. What is the category of drug names ending in - operidol (e.g. Haloperidol)
Butyrophenone (neuroleptic).
Activates antithrombin III
Liver
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

10. IV Penicillin
sedation - positive Coombs' test
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Penicillin - G

11. Which drug(s) cause this reaction: Tendonitis and rupture?
cross - allergenic
Methylxanthine.
Ca2+ (Loops Lose calcium)
- Fluoroquinolones

12. How are the HIV drugs used clinically?

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13. What are three clinical uses of the Leuprolide?
Aminoglycosides
Chronic gout.
Indirect agonist - uptake inhibitor
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids

14. Mannitol - site of action?
proximal convoluted tubule - thin descending limb - and collecting duct
Penicillin - V
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
anticholinesterase glaucoma

15. Furosemide - toxicity? (OH DANG)
Early myocardial infarction.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

16. Why would dopamine be useful in treating shock?
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

17. Which RT inhibitor causes Megaloblastic Anemia?
INH: Injures Neurons and Hepatocytes
Aminoglycosides - Tetracyclines
AZT
first dose orthostatic hypotension - dizziness - headache

18. Aztreonam is not usually...
Rash - Pseudomembranous colitis
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
toxic
Polymyxins

19. How is Vancomycin used clinically?
- Shifts the curve down - reduces Vmax
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
For serious - Gram + multidrug - resistant organisms
Rifampin (DOC) - minocycline

20. Which diuretics increase urine Ca2+?
loop diuretics - spironolactone
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Malaria (P. falciparum)
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

21. What is the MOA for Ampicillin and Amoxicillin?
Same as penicillin. Extended spectrum antibiotics
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
AluMINIMUM amount of feces.

22. Decrease Digitoxin dose in renal failure?
Rapid (seconds)
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
NO

23. Does Heparin have a long - medium - or short half life?
Short.
-100% oxygen - hyperbaric
very short acting
Blocks Influenza A and RubellA; causes problems with the cerebellA

24. Furosemide - clinical use?
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Bacitracin - Vancomycin
Suramin
pulmonary edema - dehydration

25. What is the mechanism of action of Acetaminophen?
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

26. Antiarrhythmic class IC- effects?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Tendonitis and Tendon rupture
Benzathine penicillin G

27. Resistance mechanisms for Cephalosporins/Penicillins
Interstitial nephritis
Beta - lactamase cleavage of Beta - lactam ring
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Beta lactams - inhibit cell wall synthesis - Bactericidal

28. Antimicrobial prophylaxis for Meningococcal infection
- Tricyclic antidepressants
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Binding to the presynaptic alpha 2 release modulating receptors
Rifampin (DOC) - minocycline

29. MOA of Succinylcholine
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
collecting ducts
Prevents the release of Ca from SR of skeletal muscle
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.

30. List the specific antidote for this toxin: Beta Blockers
CMV - esp in Immunocompromised patients
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Neomycin
- Glucagon

31. Antimicrobial prophylaxis for a history of recurrent UTIs
TMP- SMZ
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Activates antithrombin III
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.

32. What is the mechanism of action of Ticlopidine - Clopidogrel
Saquinavir - Ritonavir - Indinavir - Nelfinavir
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

33. What are two types of drugs that interfere with the action of Sucralfate and why?
Quinolones
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
atropine - homatropine - tropicamide
- Ethanol - dialysis - & fomepizole

34. What is the mechanism of action of Probenacid used to treat chronic gout?
Potent immunosuppressive used in organ transplant recipients.
Inhibits reabsorption of uric acid.
Decreased uptake or Increased transport out of cell
GI upset - Superinfections - Skin rashes - Headache - Dizziness

35. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Beta -2 agonist.
Penicillin.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

36. List the specific antidote for this toxin: Antimuscarinic (anticholinergic)
Acute gout.
TMP- SMZ
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
- Physostigmine salicylate

37. Resistance mechanisms for Tetracycline
Decreased uptake or Increased transport out of cell
Potent immunosuppressive used in organ transplant recipients.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

38. Furosemide - class and mechanism?
Constant FRACTION eliminated per unit time.(exponential)
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Bacitracin - Vancomycin

39. Name the common Azoles
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Minor hepatotoxicity - Drug interactions (activates P450)
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

40. Adverse effects of Minoxidil?
HTN - CHF - calcium stone formation - nephrogenic DI.
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
PT

41. What is the effect of the Glitazones in diabetes treatment?
HTN - CHF - calcium stone formation - nephrogenic DI.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Increase target cell response to insulin.
- Protamine

42. Which drug(s) cause this reaction: Aplastic anemia (5)?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
HTN - CHF - calcium stone formation - nephrogenic DI.
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
new arrhythmias - hypotension

43. Which cancer drugs work at the level of proteins(2)?
- Vinca alkaloids(inhibit MT) - Paclitaxel
Intrathecally
- Atropine & pralidoxime
Captopril - Enalapril - Lisinopril

44. What is the MOA of Ganciclovir?
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Inhibits CMV DNA polymerase
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

45. Digoxin v. Digitoxin: half life?
Beta antagonist.
Digitoxin 168hrs Digoxin 40 hrs
- Daunorubicin & Doxorubicin
Chronic anticoagulation.

46. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
Same as penicillin. Act as narrow spectrum antibiotics
PT
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
penicillinase resistant

47. What are two mechanisms of action of Propythiouracil?
- Steroids - Tamoxifen
Methicillin - Nafcillin - and Dicloxacillin
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Indirect agonist - uptake inhibitor

48. What is the most common cause of Pt noncompliance with Macrolides?
CL= (rate of elimination of drug/ Plasma drug conc.)
hypertension - CHF - diabetic renal disease
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
GI discomfort

49. What is the clinical use for Ampicillin and Amoxicillin?
propanolol - esmolol - metoprolol - atenolol - timolol
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450

50. Which drug(s) cause this reaction: Diabetes insipidus?
post MI and digitalis induced arrhythmias
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
- Lithium