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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 Metronidazole?
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.
Oral
Antifungal.
Forms toxic metabolites in the bacterial cell - Bactericidal

2. Describe Phase II metabolism in liver(3)?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Phosphorylation by a Viral Kinase
Verapamil - Diltiazem - Bepridil

3. What are common toxicities associated with Macrolides? (4)
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Leukotrienes increasing bronchial tone.
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

4. What is the clinical use for Nystatin?
effective in torsade de pointes and digoxin toxicity
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Topical and Oral - for Oral Candidiasis (Thrush)
Gram + cocci - Gram - rods - and Anerobes

5. How does angiotensin II affect NE release?
Large anionic polymer - acidic
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
It acts presynaptically to increase NE release.
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.

6. What is action of insulin in the liver - in muscle - and in adipose tissue?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
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.
penicillinase resistant

7. Which RT inhibitors cause Lactic Acidosis?
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Nucleosides
AZT - to reduce risk of Fetal Transmission

8. How do Sulfonamides act on bacteria?
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
TMP- SMZ (DOC) - aerosolized pentamidine
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome

9. ACE inhibitors - mechanism?
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Indomethacin is used to close a patent ductus arteriosus.
1. Antiandrogen 2. Nausea 3. Vomiting

10. What are two conditions in Which COX-2 inhibitors might be used?
Prevents the release of Ca from SR of skeletal muscle
Rheumatoid and osteoarthritis.
Methicillin - Nafcillin - and Dicloxacillin
Captopril - Enalapril - Lisinopril

11. For Warfarin What is the Mechanism of action
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Impairs the synthesis of vitamin K- dependent clotting factors

12. What is the MOA for Amphotericin B?
- Disulfram & also sulfonylureas - metronidazole
Local anesthetic.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

13. What is the clinical use for Sucralfate?
Peptic ulcer disease.
Liver
Give an antichloinesterase - neostigmine - edrophonium - etc
Ataxia - Dizziness - Slurred speech

14. Acetazolamide - toxicity?
troponin - tropomyosin system
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
cardiac depression - peripheral edema - flushing - dizziness - constipation
Sotalol - Ibutilide - Bretylium - Amiodarone

15. What is the memory key involving the '4 R's of Rifampin?'
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.
VACUUM your Bed Room'
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
CMV - esp in Immunocompromised patients

16. K+ sparing diuretics - toxicity?
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
proximal convoluted tubule - thin descending limb - and collecting duct
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)

17. While at a tail gait party - you bite into a sandwich that a yellow jacket is also enjoying. Knowing your allergy to this creature - What should you do?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Flecainide - Encainide - Propafenone
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

18. What is the clinical utility of clonidine?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

19. Which drug(s) cause this reaction: Hot flashes?
- Tamoxifen
- Nitrate - hydroxocobalamin thiosulfate
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Quinidine - Amiodarone - Procainamide - Disopyramide

20. Which drug(s) cause this reaction: Agranulocytosis (3)?
Interstitial nephritis
- Cloazapine - carbamazapine - colchicine - PTU
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Pregnant women - Children; because animal studies show Damage to Cartilage

21. Antiarrhythmic class IV- toxicity?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Choline acetyltransferase
Nephrotoxicity
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

22. Ca2+ channel blockers - clinical use?
post MI and digitalis induced arrhythmias
Polymyxins
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
hypertension - angina - arrhythmias

23. What is the clinical use of Mifepristone (RU486)?
Polymyxins
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Digitoxin 168hrs Digoxin 40 hrs
Abortifacient.

24. What is the clinical use for Penicillin?
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
- Phenytoin
Penicillin - V
INH: Injures Neurons and Hepatocytes

25. What is the clinical use for Heparin?
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Acetylcholinesterase; ACh is broken down into choline and acetate.
aPTT (intrinsic pathway)

26. List the mechanism - clinical use - & toxicity of 6 MP.
Chronic Hepatitis A and B - Kaposi's Sarcoma
Hemolytic anemia
anticholinesterase glaucoma
- inhibits HGPRT (pur. Syn.) - Luk - Lymph

27. How is Foscarnet used clinically?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
CMV Retinitis in IC pts When Ganciclovir fails
blocks SR Ca2+ channels
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

28. How is Chloramphenical used clinically?
For serious - Gram + multidrug - resistant organisms
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
blocks SR Ca2+ channels
Inhalational general anesthetic.

29. Adverse effects of Loop Diuretics?
Severe Gram - rod infections.
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
loop diuretics - thiazides

30. What do Aminoglycosides require for uptake?
Dopamine; causes its release from intact nerve terminals
Oxygen
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

31. What are the clinical uses for 1st Generation Cephalosporins?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
No - it inhibits the release of Nor Epi
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

32. What is the memory key for Metronidazole's clinical uses?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
distal convoluted tubule (early)
Doxycycline - because it is fecally eliminated
GET on the Metro

33. What is the category - desired effect - and possible mechanism of Theophylline in treating Asthma?
Tetracycline - Doxycycline - Demeclocycline - Minocycline
1. Renal damage 2. Aplastic anemia 3. GI distress
Prevents the release of ACh - Which results in muscle paralysis.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

34. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Botulinum
It inhibits release of NE.

35. Name five Antiarrhythmic drugs in class II?
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
- Cloazapine - carbamazapine - colchicine - PTU
propanolol - esmolol - metoprolol - atenolol - timolol
Praziquantel

36. What is a Ribavirin toxicity?
PT
Hemolytic anemia
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Amphotericin B - Nystatin - Fluconazole/azoles

37. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
CL= (rate of elimination of drug/ Plasma drug conc.)
severe hypertension - CHF
- Atropine & pralidoxime

38. Which diuretics decrease urine Ca2+?
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.
thiazides - amiloride
Acetylcholine esterase
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.

39. What are two toxicities of the Glitazones?
- Phenytoin
Cardiac glycoside (inotropic agent).
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
1. Weight gain 2. Hepatotoxicity (troglitazone)

40. What is the mechanism of Tacrolimus (FK506)?
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Indomethacin is used to close a patent ductus arteriosus.
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

41. Which drug(s) cause this reaction: Atropine - like side effects?
Keratin containing tissues - e.g. - nails
- Tricyclic antidepressants
Short.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

42. Which diuretics cause acidosis?
Polymyxins
Aminoglycosides - Tetracyclines
carbonic anhydrase inhibitors - K+ sparing diuretics
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

43. Which individuals are predisposed to Sulfonamide - induced hemolysis?
PT
Beta - lactam antibiotics
G6PD deficient individuals
Tendonitis and Tendon rupture

44. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
Same as penicillin. Act as narrow spectrum antibiotics
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention

45. When is Rifampin not used in combination with other drugs?
Aplastic anemia (dose independent) - Gray Baby Syndrome
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
- Haloperidol - chlorpromazine - reserpine - MPTP

46. Which drug(s) cause this reaction: Cinchonism (2)?
- Tetracycline - amiodarone - sulfonamides
Diarrhea
Acetylcholine esterase
- Quinidine - quinine

47. Why would you give a drug like pancuronium or succinylcholine?
Useful in muscle paralysis during surgery or mechanical ventilation.
H2 antagonist
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Imipenem

48. What is the MOA for the Aminoglycosides?
distal convoluted tubule (early)
hyperaldosteronism - K+ depletion - CHF
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Increase target cell response to insulin.

49. How is Ganciclovir activated?
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Phosphorylation by a Viral Kinase
Succinylcholine

50. Adverse effects of Losartan?
Aminoglycosides
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Protease inhibitor.
fetal renal toxicity - hyperkalemia