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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. List the mechanism - clinical use - & toxicity of Bleomycin.
- Glucagon
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

2. K+ sparing diuretics - site of action?
- Alkalinize urine & dialysis
new arrhythmias - hypotension
cortical collecting tubule
1. Pioglitazone 2. Rosiglitazone.

3. Side effects of Isoniazid (INH)?
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
Abortifacient.
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.

4. What is the MOA for Nystatin?
Botulinum
is resistant
Antibiotic - protein synthesis inhibitor.
Binds ergosterol - Disrupts fungal membranes

5. What is the mechanism of Azathioprine?
- aminoglycosides - loop diuretics - cisplatin
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Binding to the presynaptic alpha 2 release modulating receptors
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.

6. Toxicities associated with Acyclovir?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Delirium - Tremor - Nephrotoxicity

7. How are the Latent Hypnozoite (Liver) forms of Malaria (P. vivax - P.ovale) treated?
Primaquine
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
torsade de pointes - excessive Beta block
- ED 50 is less than the Km (less than 50% of receptors)

8. What is the mechanism of action of Clomiphene?
for RSV
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
anuria - CHF
Rare.

9. What should not be taken with Tetracyclines? / Why?
troponin - tropomyosin system
Pretreat with antihistamines and a slow infusion rate
Ipratropium
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

10. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
Hypersensitivity reactions
Flecainide - Encainide - Propafenone
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

11. For Warfarin What is the Route of administration
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
GI disturbances.
Inhibition of 50S peptidyl transferase - Bacteriostatic
Oral

12. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
AV nodal cells
GI side effects. (Indomethacin is less toxic - more commonly used.)
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)

13. What are four thrombolytics?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

14. What is the definition of zero - order kinetics? Example?
Norepinephrine (Alpha1 -2 and beta 1)
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Interferes with microtubule function - disrupts mitosis - inhibits growth
Mg = Must go to the bathroom.

15. Digoxin v. Digitoxin: half life?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
ACE inhibitor.
Digitoxin 168hrs Digoxin 40 hrs
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

16. Which diuretics cause acidosis?
carbonic anhydrase inhibitors - K+ sparing diuretics
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Succinylcholine
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

17. For Heparin What is the Lab value to monitor
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
aPTT (intrinsic pathway)
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

18. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
Hydralazine and Minoxidil
- Aminocaproic acid
CMV - esp in Immunocompromised patients
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

19. List the mechanism - clinical use - & toxicity of Methotrexate.
- Methylene blue
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Binding to the presynaptic alpha 2 release modulating receptors
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

20. What are common toxicities associated with Tetracyclines?

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21. Which drug(s) cause this reaction: Hot flashes?
Babiturate.
Inhibits CMV DNA polymerase
- Tamoxifen
Benzathine penicillin G

22. Which diuretics cause alkalosis?
- Shifts the curve down - reduces Vmax
loop diuretics - thiazides
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

23. What is a Ribavirin toxicity?
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Hemolytic anemia
Dopamine

24. Classes of antihypertensive drugs?
Resistant Gram - infections
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Increases coumadin metabolism
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

25. Which drug(s) cause this reaction: Pseudomembranous colitis?
- Clindamycin
Albuterol - tertbutaline
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
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.

26. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
scopolamine
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias

27. How is Griseofulvin used clinically?
Those patients who are taking nitrates.
Oral treatment of superficial infections
collecting ducts
Chronic anticoagulation.

28. What are two toxicities of the Sulfonylureas?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
GET on the Metro

29. Antiarrhythmic class II- mechanism?
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Does not cross

30. Why is reserpine effective in treating HTN?
GET on the Metro
Same as penicillin. Extended spectrum antibiotics
Indomethacin is used to close a patent ductus arteriosus.
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

31. Adverse effects of Methyldopa?

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32. How can the t1/2 of INH be altered?
Fast vs. Slow Acetylators
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Acute (hours)
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

33. Common toxicities associated with Griseofulvin?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Teratogenic - Carcinogenic - Confusion - Headaches
Acts as a wide spectrum carbapenem

34. 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.
torsade de pointes
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
1. Renal damage 2. Aplastic anemia 3. GI distress

35. Adverse effects of Clonidine?
TMP- SMZ
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
dry mouth - sedation - severe rebound hypertension
Penicillin.

36. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Yes - it does not cross the placenta.
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

37. Which drug(s) cause this reaction: Diabetes insipidus?
No - warfarin - unlike heparin - can cross the placenta.
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
- Lithium

38. Name the common Fluoroquinolones (6)
thiazides - amiloride
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Dopamine; causes its release from intact nerve terminals
anticholinesterase glaucoma

39. What is the mechanism of action of the Sulfonylureas?
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Inhibits Viral DNA polymerase
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

40. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Staphlococcus aureus

41. What are three possible complications of Heparin therapy?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Beta - lactamase cleavage of Beta - lactam ring
penicillinase resistant

42. What is the main clinical use for the thrombolytics?
Early myocardial infarction.
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
for RSV

43. Sotalol - toxicity?
torsade de pointes - excessive Beta block
Indirect agonist - uptake inhibitor
Abortifacient.
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

44. What effect would atropine have on a patient with peptic ulcer disease?
Activates antithrombin III
Premature infants - because they lack UDP- glucuronyl transferase
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).

45. What is the mechanism of Leuprolide?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Non - Nucleosides
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.
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

46. Foscarnet does not require activation by a...
Protamine sulfate
Neutropenia
viral kinase
Rare.

47. Which RT inhibitors cause a Rash?
sedation - sleep alterations
Give an antichloinesterase - neostigmine - edrophonium - etc
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Non - Nucleosides

48. How is Ribavirin used clinically?
Captopril - Enalapril - Lisinopril
Forms toxic metabolites in the bacterial cell - Bactericidal
Pseudomonas species and Gram - rods
for RSV

49. What is Niclosamide used for?
Polymyxin B - Polymyxin E
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

50. What are two indirect acting adrenergic agonists?
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
amphetamine and ephedrine
Penicillin - V
Activates antithrombin III