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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. Antiarrhythmic class IB- clinical uses?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
not a sulfonamide - but action is the same as furosemide
cardiac depression - peripheral edema - flushing - dizziness - constipation
post MI and digitalis induced arrhythmias

2. What is a possible result of overdose of Acetaminophen?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
toxic
Tetracycline - Doxycycline - Demeclocycline - Minocycline

3. What is the MOA of Aztreonam?
- Atropine & pralidoxime
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
- Hydralazine - Procainamide - INH - phenytoin
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

4. What are two toxicities associated with Cyclosporine?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
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.
Digoxin=urinary Digitoxin=biliary

5. Adverse effects of Nifedipine - verapamil?
dizziness - flushing - constipation (verapamil) - nausea
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.)
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Aminoglycosides - Tetracyclines

6. ACE inhibitors - mechanism?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Ca2+ (Loops Lose calcium)
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased

7. Esmolol - short or long acting?
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Rheumatoid and osteoarthritis.
very short acting
prevention of nodal arrhythmias (SVT)

8. How can Isoniazid (INH)- induced neurotoxicity be prevented?
Pyridoxine (B6) administration
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
troponin - tropomyosin system
post MI and digitalis induced arrhythmias

9. K+ sparing diuretics - toxicity?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction

10. 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.
Praziquantel
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
- Physostigmine salicylate

11. What are three toxicities of Propylthiouracil?
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
- Quinidine - quinine

12. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
ACIDazolamide' causes acidosis
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
- Glucocorticoid withdrawal

13. What is the chemical name for Ganciclovir?
- Deferoxamine
DHPG (dihydroxy-2- propoxymethyl guanine)
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

14. Adverse effects of Minoxidil?
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Oxygen
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

15. What is the MOA of the RT Inhibitors?
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Heparin catalyzes the activation of antithrombin III.
Oxygen
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

16. MOA: Block protein synthesis at 50s subunit
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
1. Renal damage 2. Aplastic anemia 3. GI distress
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
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.

17. What is the clinical use for Heparin?
- Fluoroquinolones
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
- Ethosuxamide - sulfonamides - lamotrigine

18. What are four clinical uses of glucocorticoids?

19. What is the memory key for Metronidazole's clinical uses?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Small lipid - soluble molecule
GET on the Metro
GI disturbances.

20. How is Amphotericin B administered for fungal meningitis?
fetal renal toxicity - hyperkalemia
Edrophonium
Hemolytic anemia
Intrathecally

21. Which diuretics increase urine Ca2+?
- Flumazenil
Scopolamine
loop diuretics - spironolactone
Aminoglycosides

22. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Yes
It inhibits release of NE.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Antileukotriene; blocks synthesis by lipoxygenase.

23. List the specific antidote for this toxin: Carbon monoxide
-100% oxygen - hyperbaric
cyanide toxicity (releases CN)
Pituitary hormone.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.

24. What are the clinical indications for bethanechol?
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Potent immunosuppressive used in organ transplant recipients.
Vd= (Amt. of drug in body/ Plasma drug conc.)

25. List the mechanism - clinical use - & toxicity of Vincristine.

26. What is the mechanism of action of the glucocorticoids?
Potent immunosuppressive used in organ transplant recipients.
Forms toxic metabolites in the bacterial cell - Bactericidal
Doxycycline - because it is fecally eliminated
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

27. What is the effect of the Glitazones in diabetes treatment?
Potent immunosuppressive used in organ transplant recipients.
Buy AT 30 - CELL at 50'
Blood
Increase target cell response to insulin.

28. What parasites are treated with Pyrantel Pamoate (more specific)?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
dizziness - flushing - constipation (verapamil) - nausea
Protease Inhibitors and Reverse Transcriptase Inhibitors

29. Which drug(s) cause this reaction: Tardive dyskinesia?
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
anticholinesterase glaucoma
- Antipsychotics
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

30. Digitalis - site of action?
Sulfonamides - Trimethoprim
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Na/K ATPase

31. What are the products and their toxicities of the metabolism of Methanol by / alcohol dehydrogenase?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Prophylaxis for Influenza A - Rubella; Parkinson's disease
- Formaldehyde & formic acid - severe acidosis & retinal damage
Cilastatin

32. What is the mechanism of action of Cyclosporine?
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
- Tetracycline
loop diuretics - thiazides
It affects beta receptors equally and is used in AV heart block (rare).

33. How do you treat coma in the ER (4)?
VACUUM your Bed Room'
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Useful in muscle paralysis during surgery or mechanical ventilation.
Na/K ATPase

34. Classes of antihypertensive drugs?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Gemfibrozil - Clofibrate
Neurotoxicity - Acute renal tubular necrosis
Penicillin.

35. For Heparin What is the Duration of action
Acute (hours)
carbonic anhydrase inhibitors - K+ sparing diuretics
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Rash - Pseudomembranous colitis

36. What is the main clinical use for the thrombolytics?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Inhibit Ergosterol synthesis
Early myocardial infarction.

37. What are toxicities associated with Chloramphenicol?
Aplastic anemia (dose independent) - Gray Baby Syndrome
Quinolones
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
- Aminocaproic acid

38. Side effects of Isoniazid (INH)?
It affects beta receptors equally and is used in AV heart block (rare).
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

39. What are the phases of succinylcholine neuromuscular blockade?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

40. What are two conditions in Which COX-2 inhibitors might be used?
Pseudomonas species and Gram - rods
Decreases synthesis of Mycolic Acid
Forms toxic metabolites in the bacterial cell - Bactericidal
Rheumatoid and osteoarthritis.

41. How is Ganciclovir activated?
Blocks Norepi - but not Dopamine
Phosphorylation by a Viral Kinase
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Beta Blockers

42. Describe first - order kinetics?
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Constant FRACTION eliminated per unit time.(exponential)
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Hydralazine and Minoxidil

43. What are two Glitazones?
aPTT (intrinsic pathway)
Competitive inibitor of progestins at progesterone receptors.
1. Pioglitazone 2. Rosiglitazone.
- Tetracycline

44. Cautions When using Amiodarone?
check PFTs - LFTs - and TFTs
Binds ergosterol - Disrupts fungal membranes
Due to the presence of a bulkier R group
Blocks Norepi - but not Dopamine

45. Triamterene and amiloride - mechanism?
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
block Na+ channels in the cortical collecting tubule
Succinylcholine
Yes

46. What reversal agent could a Anes give to reverse the effects of Atropine
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
TMP- SMZ (DOC) - aerosolized pentamidine
Bethanechol - Neostigmine - physostigmine

47. What is the clinical use for Nystatin?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Phenothiazine (neuroleptic - antiemetic).
Topical and Oral - for Oral Candidiasis (Thrush)

48. Name the common Nucleoside Reverse Transcriptase Inhibitors
proximal convoluted tubule - thin descending limb - and collecting duct
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
depresses ectopic pacemakers - especially in digoxin toxicity

49. What is the clinical use for Penicillin?
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Binds to the Pyrophosphate Binding Site of the enzyme
Aminoglycosides
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes

50. List the mechanism - clinical use - & toxicity of Paclitaxel.
Bethanechol - Neostigmine - physostigmine
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Methylation of rRNA near Erythromycin's ribosome binding site
- B51Naloxone / naltrexone (Narcan)