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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. MOA: Block DNA topoisomerases
RESPIre
NO
DHPG (dihydroxy-2- propoxymethyl guanine)
Quinolones

2. Which diuretics increase urine K+?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Foscarnet = pyroFosphate analog
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Benzodiazepine.

3. What are common side effects of Protease Inhibitors?
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Methylation of rRNA near Erythromycin's ribosome binding site
Phosphorylation by a Viral Kinase

4. What are the clinical indications for neostigmine?
Inhibits cell wall mucopeptide formation - Bactericidal
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

5. Antiarrhythmic class IC- effects?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
anuria - CHF
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
AZT - to reduce risk of Fetal Transmission

6. Which RT inhibitors cause Lactic Acidosis?
1. Pioglitazone 2. Rosiglitazone.
Ca2+ (Loops Lose calcium)
Due to the presence of a bulkier R group
Nucleosides

7. MOA: Block protein synthesis at 50s subunit
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Beta antagonist.
Dermatophytes (tinea - ringworm)
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

8. Resistance mechanisms for Cephalosporins/Penicillins
Beta - lactamase cleavage of Beta - lactam ring
Protease inhibitor.
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
GI discomfort

9. What is the mechanism of action of Warfarin (Coumadin)?
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
Leukotrienes increasing bronchial tone.
Gram + and Anerobes
Penicillin - V

10. Which drug(s) cause this reaction: Cardiac toxicity?
- Oxalic acid - Acidosis & nephrotoxicity
Choline acetyltransferase
- Daunorubicin & Doxorubicin
sedation - depression - nasal stuffiness - diarrhea

11. Name four HMG- CoA reductase inhibitors.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Rash - Pseudomembranous colitis
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

12. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
physostigmine

13. Cautions When using Amiodarone?
Onchocerciasis ('river blindness'-- rIVER- mectin)
for RSV
check PFTs - LFTs - and TFTs
Blood

14. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Blocks Influenza A and RubellA; causes problems with the cerebellA
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

15. What is the MOA of Polymyxins?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
-100% oxygen - hyperbaric
Topical and Oral - for Oral Candidiasis (Thrush)
Saquinavir - Ritonavir - Indinavir - Nelfinavir

16. For Heparin What is the Ability to inhibit coagulation in vitro
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
DOC in diagnosing and abolishing AV nodal arrhythmias
Yes
Topical and Oral - for Oral Candidiasis (Thrush)

17. List the mechanism - clinical use - & toxicity of Cisplatin.
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Gram + cocci - Gram - rods - and Anerobes
- Dimercaprol - succimer
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

18. For Warfarin What is the Site of action
Hypersensitivity reactions
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Liver

19. What are the side effects of Polymyxins?
Cephalosporins
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Fast vs. Slow Acetylators
Neurotoxicity - Acute renal tubular necrosis

20. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Butyrophenone (neuroleptic).
Those patients who are taking nitrates.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Intrathecally

21. For Warfarin What is the Mechanism of action
Nevirapine - Delavirdine
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Impairs the synthesis of vitamin K- dependent clotting factors

22. What are the indications for using amphetamine?

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23. Furosemide - toxicity? (OH DANG)
Nifedipine - Verapamil - Diltiazem
Yes
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

24. Which drug(s) cause this reaction: Gray baby syndrome?
Beta antagonist.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
- Chloramphenicol
depresses ectopic pacemakers - especially in digoxin toxicity

25. What is the mechanism of action of NSAIDs other than Aspirin?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

26. Name four Antiarrhythmic drugs in class III.
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Bleeding.
Tricyclic antidepressant.
Sotalol - Ibutilide - Bretylium - Amiodarone

27. List the specific antidote for this toxin: Beta Blockers
- Oxalic acid - Acidosis & nephrotoxicity
- Glucagon
Fast vs. Slow Acetylators
INH: Injures Neurons and Hepatocytes

28. What would be the effect on blood pressure with infusion of the alpha -2 agonist clonidine?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Competitive inibitor of progestins at progesterone receptors.
Butyrophenone (neuroleptic).
Benzathine penicillin G

29. Spironolactone - mechanism?
Beta -2 agonist.
Oral
competitive inhibirot of aldosterone in the cortical collecting tubule
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.

30. What is combination TMP- SMZ used to treat?
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Decreases synthesis of Mycolic Acid
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)

31. List the specific antidote for this toxin: Cyanide
Alpha -1 antagonist
- Nitrate - hydroxocobalamin thiosulfate
Oral treatment of superficial infections
cortical collecting tubule

32. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Treatment of infertility.
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Resistant Gram - infections
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

33. Which drug(s) cause this reaction: P450 induction(6)?
reversible SLE- like syndrome
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
hypertension - CHF - diabetic renal disease

34. List the mechanism - clinical use - & toxicity of 6 MP.
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
NO
Imipenem
Nifedipine - Verapamil - Diltiazem

35. Are not penicillinase resistant
Carbenicillin - Piperacillin - and Ticarcillin
Inhibits cell wall mucopeptide formation - Bactericidal
- B51Naloxone / naltrexone (Narcan)
Blocks Influenza A and RubellA; causes problems with the cerebellA

36. What is the mechanism of action of Cyclosporine?
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
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.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Does not cross

37. Which drug(s) cause this reaction: Osteoporosis (2)?
- Corticosteroids - heparin
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Beta antagonist.
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

38. Ca2+ channel blockers - clinical use?
hypertension - angina - arrhythmias
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
Due to the presence of a bulkier R group
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities

39. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
Oral treatment of superficial infections
Rash - Pseudomembranous colitis
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Praziquantel

40. List the specific antidote for this toxin: Salicylates
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
- Ethanol - dialysis - & fomepizole
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
- Alkalinize urine & dialysis

41. What are the clinical indications for Azole therapy?
Minor hepatotoxicity - Drug interactions (activates P450)
Systemic mycoses
Those patients who are taking nitrates.
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

42. Name the common Nucleoside Reverse Transcriptase Inhibitors
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
It inhibits release of NE.
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Tricyclic antidepressant.

43. List the specific antidote for this toxin: Tricyclic antidepressants
competitive inhibirot of aldosterone in the cortical collecting tubule
Pituitary hormone.
- NaHCO3
fetal renal toxicity - hyperkalemia

44. Decrease Digoxin dose in renal failure?
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
blocks SR Ca2+ channels
- Lithium
YES

45. What are Amantadine - associated side effects?
Ataxia - Dizziness - Slurred speech
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

46. Adverse effects of Losartan?
Pituitary hormone.
Hypersensitivity reactions
Phosphorylation by a Viral Kinase
fetal renal toxicity - hyperkalemia

47. What are three possible toxicities of NSAID usage?
- Normalize K+ - Lidocaine - & Anti - dig Mab
Long.
Peptic ulcer disease.
1. Renal damage 2. Aplastic anemia 3. GI distress

48. What is the major toxic side effect of Penicillin?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Quinolones
Hypersensitivity reactions

49. How does a competitive antagonist effect an agonist?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Slow - limited by half lives of clotting factors
- Tricyclic antidepressants
- Shifts the curve to the right - increases Km

50. Why would you use pralidoxime after exposure to an organophosphate?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
effective in torsade de pointes and digoxin toxicity
Pralidoxime regenerates active cholinesterase.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).