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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. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
Rifampin
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
GI upset
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

2. Ibutilide - toxicity?
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
torsade de pointes
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Large anionic polymer - acidic

3. Why does atropine dilate the pupil?
Penicillin.
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Botulinum
check PFTs - LFTs - and TFTs

4. Antiarrhythmic class IV- primary site of action?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
- Corticosteroids - heparin
Tendonitis and Tendon rupture
AV nodal cells

5. What is the clinical use for Heparin?
- Alkalate DNA - Brain tumors - CNS toxicity
- Tricyclic antidepressants
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Same as penicillin. Extended spectrum antibiotics

6. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Pralidoxime regenerates active cholinesterase.
Those patients who are taking nitrates.
AmOxicillin has greater Oral bioavailability
- Bleomycin - amiodarone - busulfan

7. How do spare receptors effect the Km?
Pseudomonas species and Gram - rods
- Quinidine - quinine
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
- ED 50 is less than the Km (less than 50% of receptors)

8. Name two bile acid resins.
Nifedipine - Verapamil - Diltiazem
- Haloperidol - chlorpromazine - reserpine - MPTP
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
cholestyramine - colestipol

9. What is the category of drug names ending in - cillin (e.g. Methicillin)
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Doxycycline - because it is fecally eliminated
Penicillin.
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)

10. Name the common Nucleoside Reverse Transcriptase Inhibitors
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Cilastatin
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

11. What is combination TMP- SMZ used to treat?
Epinephrine
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

12. What is the MOA for the Fluoroquinolones?
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
carbonic anhydrase inhibitors - K+ sparing diuretics
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal

13. How can the toxic effects of TMP be ameliorated?
Inhibit Ergosterol synthesis
Methylxanthine.
With supplemental Folic Acid
Dermatophytes (tinea - ringworm)

14. What is the MOA of Isoniazid (INH)?
Decreases synthesis of Mycolic Acid
CL= (rate of elimination of drug/ Plasma drug conc.)
Anaerobes
Malaria (P. falciparum)

15. List the specific antidote for this toxin: Lead
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Polymyxins
- EDTA - dimercaprol - succimer - & penicillamine
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

16. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Praziquantel
Because they require some residual islet function.
Saquinavir - Ritonavir - Indinavir - Nelfinavir

17. Why does NE result in bradycardia?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

18. Which of epi - norepi - or isoproterenol results in bradycardia?
Norepinephrine
post MI and digitalis induced arrhythmias
hypertension - CHF - diabetic renal disease
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

19. What is the MOA for the Tetracyclines?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
- Penicillamine
Phosphorylation by a Viral Kinase

20. Sotalol - toxicity?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
amphetamine and ephedrine
torsade de pointes - excessive Beta block
No - warfarin - unlike heparin - can cross the placenta.

21. Mannitol - site of action?
- Atropine & pralidoxime
AZT - to reduce risk of Fetal Transmission
Oral treatment of superficial infections
proximal convoluted tubule - thin descending limb - and collecting duct

22. What is the category of drug names ending in - azine (e.g. Chlorpromazine)
Phenothiazine (neuroleptic - antiemetic).
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
depresses ectopic pacemakers - especially in digoxin toxicity

23. What is treated with Chloroquine - Quinine - Mefloquine?
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Malaria (P. falciparum)
Benzathine penicillin G
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

24. Steady state concentration is reached in __ number of half - lifes
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
cardiac depression - peripheral edema - flushing - dizziness - constipation
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

25. Resistance mechanisms for Aminoglycosides
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Modification via Acetylation - Adenylation - or Phosphorylation
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

26. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Choline acetyltransferase
- Ethosuxamide - sulfonamides - lamotrigine
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Gram + - Gram - - Norcardia - Chlamydia

27. Which diuretics decrease urine Ca2+?
thiazides - amiloride
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Protamine sulfate

28. What is a sign of toxicity with the use of thrombolytics?
hyperaldosteronism - K+ depletion - CHF
Bleeding.
- Vitamin K & fresh frozen plasma
Aplastic anemia (dose independent) - Gray Baby Syndrome

29. What is the specific clinical use of Indomethacin in neonates?
- Glucocorticoid withdrawal
Indomethacin is used to close a patent ductus arteriosus.
Inhibits Viral DNA polymerase
Ibuprofen - Naproxen - and Indomethacin

30. What is a possible toxicity of Alpha - glucosidase inhibitors used in type -2 diabetes?
GI disturbances.
blocks SR Ca2+ channels
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Inhibits Viral DNA polymerase

31. What is the MOA for Rifampin?
TCA
1. Renal damage 2. Aplastic anemia 3. GI distress
Inhibits DNA dependent RNA polymerase
Disulfiram - like reaction with EtOH - Headache

32. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
sedation - depression - nasal stuffiness - diarrhea
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Norepinephrine (Alpha1 -2 and beta 1)
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

33. Antiarrhythmic class IV- effects?
new arrhythmias - hypotension
blocks SR Ca2+ channels
Yes
decrease conduction velocity - increase ERP - increase PR interval

34. What is the MOA of Ganciclovir?
Butyrophenone (neuroleptic).
Inhibits CMV DNA polymerase
Methylxanthine.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

35. Which RT inhibitors cause a Rash?
Non - Nucleosides
Staphlococcus aureus
cardiac muscle: Verapamil>Diltiazem>Nifedipine
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

36. What is the effect of epinephrine infusion on bp and pulse pressure?
Acute gout.
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
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

37. What is the category of drug names ending in - azepam (e.g. Diazepam)
Cell membrane Ca2+ channels of cardiac sarcomere
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Benzodiazepine.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

38. What is the clinical utility of clonidine?
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
DOC in diagnosing and abolishing AV nodal arrhythmias
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Megaloblastic anemia - Leukopenia - Granulocytopenia

39. Which drug(s) cause this reaction: Hepatitis?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Same as penicillin. Act as narrow spectrum antibiotics
- Isoniazid

40. What are two types of drugs that interfere with the action of Sucralfate and why?
physostigmine
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Short.

41. Furosemide - clinical use?
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
- Disulfram & also sulfonylureas - metronidazole
Beta - lactamase cleavage of Beta - lactam ring

42. Adenosine - clinical use?
DOC in diagnosing and abolishing AV nodal arrhythmias
collecting ducts
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
- Alkalinize urine & dialysis

43. Beta Blockers - CV toxicity?
- Methylene blue
bradycardia - AV block - CHF
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Triple sulfas or SMZ

44. What is the MOA of Imipenem?
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.
Rifampin (DOC) - minocycline
Beta - lactamase cleavage of Beta - lactam ring
Acts as a wide spectrum carbapenem

45. What is the category of drug names ending in - navir (e.g. Saquinavir)
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Protease inhibitor.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

46. Beta Blockers - site of action?
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Dopamine
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Beta adrenergic receptors and Ca2+ channels (stimulatory)

47. For Warfarin What is the Mechanism of action
Liver
Dobutamine has more of an affintiy for beta -1 than beta -2 - and is used for treating heart failure and shock. Albuterol and terbutaline is the reverse - and is used in treatment of acute asthma.
atropine - homatropine - tropicamide
Impairs the synthesis of vitamin K- dependent clotting factors

48. What are three toxicities of Leuprolied?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Dopamine; causes its release from intact nerve terminals
1. Antiandrogen 2. Nausea 3. Vomiting
anticholinesterase glaucoma

49. MOA of Succinylcholine
Prevents the release of Ca from SR of skeletal muscle
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Inhibit viral DNA polymerase
distal convoluted tubule (early)

50. Adverse effect of Nitroprusside?
cyanide toxicity (releases CN)
Protease inhibitor.
- aminoglycosides - loop diuretics - cisplatin
Digitoxin 70% Digoxin 20-40%