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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 are five toxicities associated with Tacrolimus (FK506)?
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Indirect agonist - uptake inhibitor
Lidocaine - Mexiletine - Tocainide
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

2. What is the mechanism of Leuprolide?
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
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
Fast vs. Slow Acetylators
loop diuretics - spironolactone

3. For Warfarin What is the Onset of action
It affects beta receptors equally and is used in AV heart block (rare).
Slow - limited by half lives of clotting factors
Onchocerciasis ('river blindness'-- rIVER- mectin)
Pyridoxine (B6) administration

4. Which drug(s) cause this reaction: Gingival hyperplasia?
Modification via Acetylation - Adenylation - or Phosphorylation
- Phenytoin
Antileukotriene; blocks synthesis by lipoxygenase.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)

5. Acetazolamide - clinical uses?
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
- aminoglycosides - loop diuretics - cisplatin
Forms toxic metabolites in the bacterial cell - Bactericidal
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness

6. ADH antagonists - site of action?
Methicillin - Nafcillin - and Dicloxacillin
collecting ducts
1. Acarbose 2. Miglitol
thick ascending limb

7. What is the memory key for the effect of aluminum hydroxide overuse?
AluMINIMUM amount of feces.
Teratogenic - Carcinogenic - Confusion - Headaches
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Bleeding.

8. What is the MOA for the Tetracyclines?
Liver
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
fetal renal toxicity - hyperkalemia
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

9. Why would you use pralidoxime after exposure to an organophosphate?
Pralidoxime regenerates active cholinesterase.
Reversible block of histamine H2 receptors
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

10. What is the mechanism of action of Acetaminophen?
competitive inhibirot of aldosterone in the cortical collecting tubule
Epinephirine(Alpha1 -2 and Beta 1 -2)
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Methylxanthine.

11. List the mechanism - clinical use - & toxicity of Etoposide.
Non - Nucleosides
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Acute gout.
Same as penicillin. Extended spectrum antibiotics

12. What are two clinical uses of Azathioprine?
Short.
proximal convoluted tubule - thin descending limb - and collecting duct
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods

13. Why is Cilastatin administered with Imipenem?
Peptic ulcer disease.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Inhibits Viral DNA polymerase
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

14. What are three toxicities of Leuprolied?
1. Antiandrogen 2. Nausea 3. Vomiting
Neurotoxicity - Acute renal tubular necrosis
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Gram + and Anerobes

15. What is the clinical utility of clonidine?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Interferes with microtubule function - disrupts mitosis - inhibits growth
hyperaldosteronism - K+ depletion - CHF
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

16. What is the formula for Clearance (CL)
CL= (rate of elimination of drug/ Plasma drug conc.)
DHPG (dihydroxy-2- propoxymethyl guanine)
Methylxanthine.
Abortifacient.

17. As an Anes you want to use a depolarizing neuromuscular blocking drug on your pt - What do you use
proarrhythmic
Succinylcholine
Beta -2 agonist.
- ED 50 is less than the Km (less than 50% of receptors)

18. What cholinomimetic is useful in the diagnosis of Myasthenia Gravis
Edrophonium
Blocks Norepi - but not Dopamine
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Prevents the release of Ca from SR of skeletal muscle

19. What is the mecanism of action of Sucralfate?
Foscarnet = pyroFosphate analog
propanolol - esmolol - metoprolol - atenolol - timolol
local anesthetic. CNS stimulation or depression. CV depression.
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.

20. Which RT inhibitors cause Lactic Acidosis?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Nucleosides
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.

21. MOA: Block nucleotide synthesis
Sulfonamides - Trimethoprim
Na/K ATPase
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

22. What is the clinical use for Heparin?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
1. Antiandrogen 2. Nausea 3. Vomiting
Immediate anticoagulation for PE - stroke - angina - MI - DVT.

23. How can the t1/2 of INH be altered?
Fast vs. Slow Acetylators
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

24. What are the phases of succinylcholine neuromuscular blockade?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Local anesthetic.
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Imipenem

25. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
dry mouth - sedation - severe rebound hypertension
Rare.
Oral
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

26. For Heparin What is the Structure
new arrhythmias - hypotension
- NaHCO3
Large anionic polymer - acidic
Amphotericin B - Nystatin - Fluconazole/azoles

27. What is the clinical use for Sildenafil (Viagra)?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Erectile dysfunction.
Beta -2 agonist.
Antileukotriene; blocks synthesis by lipoxygenase.

28. Dobutamine used for the tx of shock acts on Which receptors
Beta1 more than B2
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Primaquine

29. What are the major toxic side effects of the Cephalosporins?
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Beta1 more than B2
Na/K ATPase
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

30. Ca2+ channel blockers - site of action?
Cell membrane Ca2+ channels of cardiac sarcomere
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
anuria - CHF
Benzathine penicillin G

31. What is the mechanism of action of the Sulfonylureas?
Quinolones
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Pregnant women - Children; because animal studies show Damage to Cartilage
aPTT (intrinsic pathway)

32. Mannitol - clinical use?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Chronic gout.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Lidocaine - Mexiletine - Tocainide

33. What is the MOA of the RT Inhibitors?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
hypertension - CHF - diabetic renal disease
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

34. How are Interferons (INF) used clinically?

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35. What is the mechanism of action of Colchicine used to treat acute gout?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Aminoglycosides - Tetracyclines

36. The COX-2 inhibitors (celecoxib - rofecoxib) have similar side effects to the NSAIDs with What one exception?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Nifedipine - Verapamil - Diltiazem
Tetracycline - Doxycycline - Demeclocycline - Minocycline

37. Foscarnet toxicity?
Antileukotriene; blocks leukotriene receptors.
Carbachol - pilocarpine - physostigmine - echothiophate
Benzathine penicillin G
Nephrotoxicity

38. These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Penicillin.
Amphetamine and Ephedrine
Antifungal.

39. What are Amantadine - associated side effects?
Impairs the synthesis of vitamin K- dependent clotting factors
Ataxia - Dizziness - Slurred speech
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Vd= (Amt. of drug in body/ Plasma drug conc.)

40. What is the category of drug names ending in - phylline (e.g. Theophylline)
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Methylxanthine.
- EDTA - dimercaprol - succimer - & penicillamine
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas

41. What is the memory key for organisms treated with Tetracyclines?

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42. What cholinomimetics might your pt be taking for his glaucoma
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Carbachol - pilocarpine - physostigmine - echothiophate
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.

43. Which drug(s) cause this reaction: Cutaneous flushing (4)?
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.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
- Niacin - Ca++ channel blockers - adenosine - vancomycin

44. What parasitic condition is treated with Ivermectin?

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45. Ethacrynic Acid - mechanism?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
not a sulfonamide - but action is the same as furosemide
Quinolones
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.

46. What are two toxicities of the Glitazones?
1. Weight gain 2. Hepatotoxicity (troglitazone)
- Disulfram & also sulfonylureas - metronidazole
- Flumazenil
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction

47. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
Praziquantel
scopolamine
- Ethanol - dialysis - & fomepizole
Scopolamine

48. What is the mechanism of action of Heparin?
Heparin catalyzes the activation of antithrombin III.
pulmonary edema - dehydration
Neomycin
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

49. Which drug(s) cause this reaction: Cardiac toxicity?
Modification via Acetylation - Adenylation - or Phosphorylation
Competitive inibitor of progestins at progesterone receptors.
- Daunorubicin & Doxorubicin
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

50. Which drug(s) cause this reaction: Diabetes insipidus?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
- Lithium