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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. Ca2+ channel blockers - clinical use?
Rare.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Quinolones
hypertension - angina - arrhythmias

2. Name some common Sulfonamides (4)
first dose orthostatic hypotension - dizziness - headache
- Ethosuxamide - sulfonamides - lamotrigine
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Vd= (Amt. of drug in body/ Plasma drug conc.)

3. What is an additional side effect of Methicillin?
Impairs the synthesis of vitamin K- dependent clotting factors
Interstitial nephritis
-100% oxygen - hyperbaric
Quinidine - Amiodarone - Procainamide - Disopyramide

4. Which drug(s) cause this reaction: Atropine - like side effects?
- Tricyclic antidepressants
Erectile dysfunction.
Digitoxin>95% Digoxin 75%
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

5. What is Ketoconazole specifically used for?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Prevents the release of Ca from SR of skeletal muscle
- Oral Contraceptives

6. What is the clinical use for Sucralfate?
Peptic ulcer disease.
Acute gout.
Inhibit viral DNA polymerase
is resistant

7. What is action of insulin in the liver - in muscle - and in adipose tissue?
Delirium - Tremor - Nephrotoxicity
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Same as penicillin. Extended spectrum antibiotics
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.

8. What are the clinical uses for Imipenem/cilastatin?
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Gram + cocci - Gram - rods - and Anerobes
1. Weight gain 2. Hepatotoxicity (troglitazone)
Sotalol - Ibutilide - Bretylium - Amiodarone

9. What is a possible toxicity of Alpha - glucosidase inhibitors used in type -2 diabetes?
depresses ectopic pacemakers - especially in digoxin toxicity
Heparin catalyzes the activation of antithrombin III.
GI disturbances.
Oral treatment of superficial infections

10. What is the mechanism of Azathioprine?
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.

11. What is the MOA for the Cephalosporins?
Beta lactams - inhibit cell wall synthesis - Bactericidal
Digitoxin 70% Digoxin 20-40%
new arrhythmias - hypotension
Epinephirine(Alpha1 -2 and Beta 1 -2)

12. Which drug(s) cause this reaction: Hot flashes?
- Tamoxifen
Hypersensitivity reactions
Large anionic polymer - acidic
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

13. Which diuretics cause alkalosis?
loop diuretics - thiazides
The PTT.
- Phenytoin
sedation - sleep alterations

14. What is the category of drug names ending in - azol (e.g. Ketoconazole)
PT
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Pyridoxine (B6) administration
Antifungal.

15. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
Gram + - Gram - - Norcardia - Chlamydia
GI upset - Superinfections - Skin rashes - Headache - Dizziness
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Praziquantel

16. Describe the MOA of Interferons (INF)
Ceftriaxone
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
Ca2+ (Loops Lose calcium)
ACE inhibitor.

17. List the specific antidote for this toxin: Iron
- Phenytoin
Nevirapine - Delavirdine
- Deferoxamine
Choline acetyltransferase

18. Digoxin v. Digitoxin: bioavailability?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Constant FRACTION eliminated per unit time.(exponential)
Digitoxin>95% Digoxin 75%
Minor hepatotoxicity - Drug interactions (activates P450)

19. What is the mechanism of action of Heparin?
Prevents the release of ACh - Which results in muscle paralysis.
hyperaldosteronism - K+ depletion - CHF
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Heparin catalyzes the activation of antithrombin III.

20. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
Useful in muscle paralysis during surgery or mechanical ventilation.
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Those patients who are taking nitrates.
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

21. List the specific antidote for this toxin: Lead
1. Antiandrogen 2. Nausea 3. Vomiting
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Polymyxin B - Polymyxin E
- EDTA - dimercaprol - succimer - & penicillamine

22. What is the mechanism of action of Mifepristone (RU486)?
Dopamine; causes its release from intact nerve terminals
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Competitive inibitor of progestins at progesterone receptors.
- Glucocorticoid withdrawal

23. Aztreonam ________ to penicillinase
Neurotoxicity - Acute renal tubular necrosis
Albuterol - tertbutaline
is resistant
Inhibt Assembly of new virus by Blocking Protease Enzyme

24. For Heparin What is the Treatment for overdose
Erectile dysfunction.
Botulinum
Protamine sulfate
- Alkalinize urine & dialysis

25. What is a possible result of overdose of Acetaminophen?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

26. What is the MOA for the Fluoroquinolones?
Vd= (Amt. of drug in body/ Plasma drug conc.)
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
Captopril - Enalapril - Lisinopril

27. What is the mechanism of action of Probenacid used to treat chronic gout?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
edrophonium (extremely short acting anticholinesterase)
Dopamine; causes its release from intact nerve terminals
Inhibits reabsorption of uric acid.

28. What should not be taken with Tetracyclines? / Why?
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Mebendazole/Thiabendazole - Pyrantel Pamoate
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

29. What is the category of drug names ending in - oxin (e.g. Digoxin)
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Mg = Must go to the bathroom.
Cardiac glycoside (inotropic agent).
Binds to the Pyrophosphate Binding Site of the enzyme

30. Ca2+ sensitizers'- site of action?
- Fluoroquinolones
troponin - tropomyosin system
Interstitial nephritis
Pseudomembranous colitis (C. difficile) - fever - diarrhea

31. What is the lab value used to monitor the effectiveness of Heparin therapy?
Succinylcholine
BM suppression (neutropenia - anemia) - Peripheral neuropathy
The PTT.
Short.

32. What is the MOA of Isoniazid (INH)?
Decreases synthesis of Mycolic Acid
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Pentamidine

33. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
Premature infants - because they lack UDP- glucuronyl transferase
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
scopolamine
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

34. What are the clinical uses for 1st Generation Cephalosporins?
proximal convoluted tubule - thin descending limb - and collecting duct
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
YES
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

35. Adverse effects of Reserpine?
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
sedation - depression - nasal stuffiness - diarrhea
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

36. What is a common side effect of Misoprostol?
Diarrhea
Chronic gout.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Aplastic anemia (dose independent) - Gray Baby Syndrome

37. What can result due to antacid overuse?
Triple sulfas or SMZ
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Albuterol - tertbutaline
Those patients who are taking nitrates.

38. Foscarnet toxicity?
Hypersensitivity reactions
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Nephrotoxicity

39. K+ sparing diuretics - clinical use?
AV nodal cells
hyperaldosteronism - K+ depletion - CHF
Malaria (P. falciparum)
Liver

40. List the mechanism - clinical use - & toxicity of Nitrosureas.
Protamine sulfate
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
- Alkalate DNA - Brain tumors - CNS toxicity
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

41. MOA of Succinylcholine
Prevents the release of Ca from SR of skeletal muscle
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
- Ammonium Chloride

42. Antimicrobial prophylaxis for Meningococcal infection
Rifampin (DOC) - minocycline
Succinylcholine
- EDTA - dimercaprol - succimer - & penicillamine
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.

43. For Warfarin What is the Ability to inhibit coagulation in vitro
No
Give an antichloinesterase - neostigmine - edrophonium - etc
Cardiac glycoside (inotropic agent).
Severe Gram - rod infections.

44. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
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.
- Dimercaprol - succimer
Antibiotic - protein synthesis inhibitor.
- Tricyclic antidepressants

45. What is the effect of epinephrine infusion on bp and pulse pressure?
Blocks Influenza A and RubellA; causes problems with the cerebellA
first dose orthostatic hypotension - dizziness - headache
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
- Tamoxifen

46. Which cancer drugs effect nuclear DNA (4)?
GI discomfort
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
AZT
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

47. For Heparin What is the Onset of action
Rapid (seconds)
all of them
collecting ducts
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide

48. Decrease Digitoxin dose in renal failure?
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
NO
Nitrates
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.

49. MOA: Block peptidoglycan synthesis
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Bacitracin - Vancomycin

50. Does Ampicillin or Amoxicillin have a greater oral bioavailability?
Gram + and Anerobes
DHPG (dihydroxy-2- propoxymethyl guanine)
AmOxicillin has greater Oral bioavailability
Polymyxin B - Polymyxin E