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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. Which drug(s) cause this reaction: Anaphylaxis?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
- Penicillin

2. How do spare receptors effect the Km?
Binding to the presynaptic alpha 2 release modulating receptors
- ED 50 is less than the Km (less than 50% of receptors)
- Methylene blue
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

3. Which cancer drugs work at the level of mRNA(2)?
- Steroids - Tamoxifen
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
It acts presynaptically to increase NE release.

4. What is the mechanism of action of Aspirin?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
1. Antiandrogen 2. Nausea 3. Vomiting
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

5. What is the chemical name for Ganciclovir?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
DHPG (dihydroxy-2- propoxymethyl guanine)
- Act on same receptor - Full has greater efficacy
It inhibits release of NE.

6. List the specific antidote for this toxin: Tricyclic antidepressants
Rheumatoid and osteoarthritis.
Rapid (seconds)
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
- NaHCO3

7. Which drug(s) cause this reaction: Gynecomastia (6)?
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
post MI and digitalis induced arrhythmias
Large anionic polymer - acidic

8. Steady state concentration is reached in __ number of half - lifes
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Captopril - Enalapril - Lisinopril
VACUUM your Bed Room'
Aminoglycosides - Tetracyclines

9. What is the clinical use of Mifepristone (RU486)?
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Short.
Abortifacient.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

10. What are the nondepolarizing neuromuscular blocking drugs?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Megaloblastic anemia - Leukopenia - Granulocytopenia
For serious - Gram + multidrug - resistant organisms

11. Preferential action of the Ca2+ channel blockers at cardiac muscle?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
cardiac muscle: Verapamil>Diltiazem>Nifedipine
As an anticholinesterase it increases endogenous ACh and thus increases strength.

12. What type of patient should not take Misoprostol and why?
dizziness - flushing - constipation (verapamil) - nausea
- NaHCO3
Inhibt Assembly of new virus by Blocking Protease Enzyme
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

13. How is Foscarnet used clinically?
CMV Retinitis in IC pts When Ganciclovir fails
Flecainide - Encainide - Propafenone
Binds to the Pyrophosphate Binding Site of the enzyme
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

14. What is the clinical use for Clomiphene?
- Tamoxifen
Treatment of infertility.
anticholinesterase glaucoma
is resistant

15. Which drug(s) cause this reaction: Thrombotic complications?
- Oral Contraceptives
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
- Tetracycline
Hypersensitivity reactions

16. Antiarrhythmic class II- toxicity?
Ibuprofen - Naproxen - and Indomethacin
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Amphetamine and Ephedrine

17. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
- Methotrexate - 5 FU - 6 mercaptopurine
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Dopamine

18. What is the MOA of Isoniazid (INH)?
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.
Decreases synthesis of Mycolic Acid
Quinidine - Amiodarone - Procainamide - Disopyramide
Activates antithrombin III

19. Why are the Sulfonylureas inactive in IDDM (type -1)?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Because they require some residual islet function.
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
1. Renal damage 2. Aplastic anemia 3. GI distress

20. What neurotransmitter does Amantadine affect? How does it influence this NT?
Malaria (P. falciparum)
Dopamine; causes its release from intact nerve terminals
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Tendonitis and Tendon rupture

21. What is the only depolarizing neuromuscular blocking agent?
Succinylcholine
Slow - limited by half lives of clotting factors
Suramin
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

22. Which drug(s) cause this reaction: Osteoporosis (2)?
Bacitracin - Vancomycin
Imipenem
- Corticosteroids - heparin
proximal convoluted tubule - thin descending limb - and collecting duct

23. List the specific antidote for this toxin: Acetaminophen
- N- acetylcystine
severe hypertension - CHF
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
- Shifts the curve down - reduces Vmax

24. Which drug(s) cause this reaction: Diabetes insipidus?
GET on the Metro
proarrhythmic
Ceftriaxone
- Lithium

25. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
carbonic anhydrase inhibitors - K+ sparing diuretics
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

26. Why are Methicillin - Nafcillin - and Dicloxacillin penicillinase resistant?
cardiac depression - peripheral edema - flushing - dizziness - constipation
- Atropine & pralidoxime
Due to the presence of a bulkier R group
proximal convoluted tubule

27. Adverse effects of Nifedipine - verapamil?
dizziness - flushing - constipation (verapamil) - nausea
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
-100% oxygen - hyperbaric
decrease conduction velocity - increase ERP - increase PR interval

28. What enzyme does Zileuton inhibit?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
loop diuretics - spironolactone
Lipoxygenase
With supplemental Folic Acid

29. Ganciclovir associated toxicities?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Used in combination therapy with SMZ to sequentially block folate synthesis
Cardiac glycoside (inotropic agent).

30. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Beta - lactam antibiotics
Choline acetyltransferase
HTN - CHF - calcium stone formation - nephrogenic DI.
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

31. Name four Antiarrhythmic drugs in class IA.
- polymyxins
- Normalize K+ - Lidocaine - & Anti - dig Mab
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Quinidine - Amiodarone - Procainamide - Disopyramide

32. What are the indications for using amphetamine?

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33. Name the common Nucleoside Reverse Transcriptase Inhibitors
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Praziquantel
- Lithium

34. Furosemide - clinical use?
Succinylcholine
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Local anesthetic.
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic

35. Classes of antihypertensive drugs?
Polymyxin B - Polymyxin E
atropine - homatropine - tropicamide
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

36. The COX-2 inhibitors (celecoxib - rofecoxib) have similar side effects to the NSAIDs with What one exception?
Diuresis in pateints with sulfa allergy
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
hypertension - CHF - diabetic renal disease

37. Loop diuretics (furosemide)- site of action?
- polymyxins
Due to the presence of a bulkier R group
thick ascending limb
Triple sulfas or SMZ

38. ACE inhibitors - mechanism?
decrease conduction velocity - increase ERP - increase PR interval
sedation - positive Coombs' test
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.

39. List the specific antidote for this toxin: Opioids
- B51Naloxone / naltrexone (Narcan)
TMP- SMZ (DOC) - aerosolized pentamidine
The PTT.
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic

40. List the specific antidote for this toxin: Methanol & Ethylene glycol
hypertension - CHF - diabetic renal disease
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
- Ethanol - dialysis - & fomepizole
GI side effects. (Indomethacin is less toxic - more commonly used.)

41. MOA: Disrupt bacterial/fungal cell membranes
physostigmine
Polymyxins
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
torsade de pointes - excessive Beta block

42. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
It acts presynaptically to increase NE release.
loop diuretics - spironolactone
Pituitary hormone.

43. What drug is given for Pneumocystis carinii prophylaxis?
Pentamidine
Oral
Protease inhibitor.
Inhibits reabsorption of uric acid.

44. List the specific antidote for this toxin: Benzodiazepines
Heparin catalyzes the activation of antithrombin III.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
proximal convoluted tubule
- Flumazenil

45. What is the mechanism of action of NSAIDs other than Aspirin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- EDTA - dimercaprol - succimer - & penicillamine
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.

46. What are signs of Sildenafil (Viagra) toxicity?
Headache - flushing - dyspepsia - blue - green color vision.
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Hemolytic anemia
Ataxia - Dizziness - Slurred speech

47. What is a Ribavirin toxicity?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Hemolytic anemia

48. Which diuretics decrease urine Ca2+?
Spironolactone - Triamterene - Amiloride (the K+ STAys)
Ca2+ (Loops Lose calcium)
Butyrophenone (neuroleptic).
thiazides - amiloride

49. What is the MOA of Aztreonam?
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
AZT - to reduce risk of Fetal Transmission

50. Which drug(s) cause this reaction: Pseudomembranous colitis?
Acetylcholine esterase
Reversible block of histamine H2 receptors
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
- Clindamycin