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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 enzyme is responsible for the breakdown of ACh in the synaptic cleft?
thick ascending limb
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Acetylcholinesterase; ACh is broken down into choline and acetate.
Pentamidine

2. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
Neomycin
Cyclooxygenases (COX I - COX II).
- Bleomycin - amiodarone - busulfan
Dopamine

3. Which H2 Blocker has the most toxic effects and What are they?
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.
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
torsade de pointes
Lidocaine - Mexiletine - Tocainide

4. What is the category of drug names ending in - cycline (e.g. Tetracycline)
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Antibiotic - protein synthesis inhibitor.
Pituitary hormone.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)

5. How does botulinum toxin result in respiratory arrest?
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Lidocaine - Mexiletine - Tocainide
Prevents the release of ACh - Which results in muscle paralysis.
- Tetracycline

6. What are the major toxic side effects of the Cephalosporins?
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Lipoxygenase
Indomethacin is used to close a patent ductus arteriosus.
- Quinidine - quinine

7. ACE inhibitors - toxicity?
Aplastic anemia (dose independent) - Gray Baby Syndrome
- Disulfram & also sulfonylureas - metronidazole
Ibuprofen - Naproxen - and Indomethacin
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

8. For Warfarin What is the Lab value to monitor
PT
Babiturate.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
GI discomfort

9. What is the MOA of Ganciclovir?
Nifedipine - Verapamil - Diltiazem
- Hydralazine - Procainamide - INH - phenytoin
Blocks Norepi - but not Dopamine
Inhibits CMV DNA polymerase

10. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
Ganciclovir is more toxic to host enzymes
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

11. What is the MOA for Clindamycin?
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)

12. What is used to reverse the action of Heparin?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Beta Blockers
Erythromycin - Azithromycin - Clarithromycin
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

13. What are the clinical indications for bethanechol?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
- Ethanol - dialysis - & fomepizole
- Tetracycline - amiodarone - sulfonamides
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)

14. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
1. Antiandrogen 2. Nausea 3. Vomiting
- Chloramphenicol
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Binding to the presynaptic alpha 2 release modulating receptors

15. What are the major structural differences between Penicillin and Cephalosporin?
Fast vs. Slow Acetylators
Decreases synthesis of Mycolic Acid
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)
toxic

16. Which drug(s) cause this reaction: Torsade de pointes (2)?
Oxygen
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
TMP- SMZ
- Hydralazine - Procainamide - INH - phenytoin

17. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Butyrophenone (neuroleptic).
AZT
Rare.
Epinephirine(Alpha1 -2 and Beta 1 -2)

18. Why would dopamine be useful in treating shock?
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
hypertension - angina - arrhythmias
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.

19. Which drug(s) cause this reaction: Focal to massive hepatic necrosis (4)?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
1. Pioglitazone 2. Rosiglitazone.
It inhibits release of NE.
DHPG (dihydroxy-2- propoxymethyl guanine)

20. What is the category of drug names ending in - ipramine (e.g. Imipramine)
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Tricyclic antidepressant.
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes

21. List the mechanism - clinical use - & toxicity of Busulfan.
depresses ectopic pacemakers - especially in digoxin toxicity
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
- ACE inhibitors (Losartan>no cough)
Pentamidine

22. Amprotericin B ___________ the BBB
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Does not cross
GI upset
Pretreat with antihistamines and a slow infusion rate

23. Furosemide increases the excretion of What ion?
AZT
Ca2+ (Loops Lose calcium)
Blood
Botulinum

24. What enzyme does Zileuton inhibit?
Lipoxygenase
Rapid (seconds)
AluMINIMUM amount of feces.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules

25. Which drug(s) cause this reaction: Agranulocytosis (3)?
Malaria (P. falciparum)
Binding to the presynaptic alpha 2 release modulating receptors
- Cloazapine - carbamazapine - colchicine - PTU
TCA

26. Describe Phase II metabolism in liver(3)?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Increase target cell response to insulin.
propanolol - esmolol - metoprolol - atenolol - timolol

27. Adverse effects of Losartan?
fetal renal toxicity - hyperkalemia
Hydralazine and Minoxidil
Beta -2 agonist.
proximal convoluted tubule

28. What is the mechanism of action of Allopurinol used to treat chronic gout?
Beta1 more than B2
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.

29. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
Sulfonamides - Trimethoprim
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Beta lactams - inhibit cell wall synthesis - Bactericidal
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.

30. What are the clinical uses for 2nd Generation Cephalosporins?
Same as penicillin. Act as narrow spectrum antibiotics
Carbachol - pilocarpine - physostigmine - echothiophate
Penicillin - V
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

31. How is Griseofulvin used clinically?
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Acetylcholine esterase
Aminoglycosides - Tetracyclines
Oral treatment of superficial infections

32. Common side effects associated with Clindamycin include?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Beta - lactam antibiotics
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Antileukotriene; blocks synthesis by lipoxygenase.

33. What is the MOA of Ribavirin?
dizziness - flushing - constipation (verapamil) - nausea
Penicillin.
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.

34. What is the MOA for the Fluoroquinolones?
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Norepinephrine
1. Renal damage 2. Aplastic anemia 3. GI distress
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.

35. Digoxin v. Digitoxin: excretion?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Digoxin=urinary Digitoxin=biliary
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
- Methotrexate - 5 FU - 6 mercaptopurine

36. List the mechanism - clinical use - & toxicity of Cisplatin.
Keratin containing tissues - e.g. - nails
- Cloazapine - carbamazapine - colchicine - PTU
Minor hepatotoxicity - Drug interactions (activates P450)
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

37. What is the loading dose formula?
- Atropine & pralidoxime
NO
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine

38. List the specific antidote for this toxin: Copper
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
- Penicillamine
Neurotoxicity - Acute renal tubular necrosis
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

39. How would you reverse the effect of a neuromuscular blocking agent?
Give an antichloinesterase - neostigmine - edrophonium - etc
Abortifacient.
- Act on same receptor - Full has greater efficacy
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

40. What are three clinical uses of the NSAIDs?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Scopolamine
Megaloblastic anemia - Leukopenia - Granulocytopenia
propanolol - esmolol - metoprolol - atenolol - timolol

41. What is the mechanism of action of Ticlopidine - Clopidogrel
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Liver
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
- EDTA - dimercaprol - succimer - & penicillamine

42. Where does Griseofulvin deposit?
Keratin containing tissues - e.g. - nails
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
anuria - CHF
competitive inhibirot of aldosterone in the cortical collecting tubule

43. What is an additional side effect of Methicillin?
Interstitial nephritis
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
As an anticholinesterase it increases endogenous ACh and thus increases strength.
The only local anesthetic with vasoconstrictive properties.

44. Name the common Nucleoside Reverse Transcriptase Inhibitors
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
- Clindamycin
YES
bradycardia - AV block - CHF

45. Ca2+ channel blockers - clinical use?
Oral treatment of superficial infections
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
hypertension - angina - arrhythmias

46. What type of neurological blockade would hexamethonium create?
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Flecainide - Encainide - Propafenone
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

47. Which drug(s) cause this reaction: Aplastic anemia (5)?
Enterobacter
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

48. What are two processes Corticosteroids inhibit leading to decreased inflammation?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
- Atropine & pralidoxime

49. How would you treat African Trypanosomiasis (sleeping sickness)?
- Protamine
- Shifts the curve to the right - increases Km
Suramin
Binding to the presynaptic alpha 2 release modulating receptors

50. What drug is used to diagnose myasthenia gravis?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
edrophonium (extremely short acting anticholinesterase)
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
- acetylation - glucuron. - & sulfation - Conjugation - Polar product