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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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 is the clinical use for Heparin?
- Glucocorticoid withdrawal
prevention of nodal arrhythmias (SVT)
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Hemolytic anemia

2. Adverse effects of Reserpine?
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Hypersensitivity reactions
- Shifts the curve down - reduces Vmax
sedation - depression - nasal stuffiness - diarrhea

3. Can Heparin be used during pregnancy?
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Yes - it does not cross the placenta.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
IV vitamin K and fresh frozen plasma

4. Where does Griseofulvin deposit?
Spironolactone - Triamterene - Amiloride (the K+ STAys)
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.
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Keratin containing tissues - e.g. - nails

5. What are four Sulfonylureas?
Babiturate.
TMP- SMZ
- Clindamycin
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

6. Which diuretics increase urine K+?
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
- Glucocorticoid withdrawal
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Acetylcholine esterase

7. Toxic side effects of the Azoles?
Pentavalent Antimony
- aminoglycosides - loop diuretics - cisplatin
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

8. List the mechanism - clinical use - & toxicity of Methotrexate.
GI disturbances.
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Rare.
Succinylcholine

9. List the specific antidote for this toxin: Lead
pulmonary edema - dehydration
- EDTA - dimercaprol - succimer - & penicillamine
Scopolamine
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

10. Adverse effects of Nifedipine - verapamil?
dizziness - flushing - constipation (verapamil) - nausea
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Inhibits reabsorption of uric acid.
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.

11. For Warfarin What is the Lab value to monitor
PT
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
sedation - positive Coombs' test
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.

12. 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.
Same as penicillin. Act as narrow spectrum antibiotics
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

13. MOA: Bactericidal antibiotics
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole
Tendonitis and Tendon rupture
- Penicillin
blocks SR Ca2+ channels

14. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
proximal convoluted tubule - thin descending limb - and collecting duct
sedation - positive Coombs' test

15. What is the memory key for the effect of magnesium hydroxide overuse?
-100% oxygen - hyperbaric
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Tendonitis and Tendon rupture
Mg = Must go to the bathroom.

16. How do Sulfonamides act on bacteria?
decrease conduction velocity - increase ERP - increase PR interval
Ca2+ (Loops Lose calcium)
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

17. What is the category of drug names ending in - caine (e.g. Lidocaine)
Local anesthetic.
viral kinase
- B51Naloxone / naltrexone (Narcan)
Hypersensitivity reactions

18. Nifedipine has similar action to?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Nitrates
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
proximal convoluted tubule - thin descending limb - and collecting duct

19. What are two processes Corticosteroids inhibit leading to decreased inflammation?
Resistant Gram - infections
Pituitary hormone.
Penicillin - G
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes

20. How do we stop angina?
not a sulfonamide - but action is the same as furosemide
Same as penicillin. Extended spectrum antibiotics
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
- Penicillin

21. What is Fluconazole specifically used for?
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
GI upset
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.

22. What drugs target anticholinesterase
Prevents the release of Ca from SR of skeletal muscle
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
cholestyramine - colestipol
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

23. How do you calculate maintenance dose?
Penicillin.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Chronic (weeks or months)
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise

24. What are common toxic side effects of Sulfonamides? (5)
- Tricyclic antidepressants
DHPG (dihydroxy-2- propoxymethyl guanine)
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Ataxia - Dizziness - Slurred speech

25. ACE inhibitors - mechanism?
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
- NaHCO3
- Penicillin

26. Which drug(s) cause this reaction: Anaphylaxis?
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.
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
- Penicillin
Butyrophenone (neuroleptic).

27. MOA: Disrupt fungal cell membranes
Small lipid - soluble molecule
Amphotericin B - Nystatin - Fluconazole/azoles
- Cloazapine - carbamazapine - colchicine - PTU
- Clindamycin

28. What are two conditions in Which COX-2 inhibitors might be used?
Binding to the presynaptic alpha 2 release modulating receptors
Rheumatoid and osteoarthritis.
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

29. How is Leishmaniasis treated?
Pentavalent Antimony
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Ipratropium
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

30. Does Warfarin have a long - medium - or short half life?
Digoxin=urinary Digitoxin=biliary
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Long.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.

31. Name four Antiarrhythmic drugs in class IA.
- ED 50 is less than the Km (less than 50% of receptors)
- Protamine
Amphotericin B - Nystatin - Fluconazole/azoles
Quinidine - Amiodarone - Procainamide - Disopyramide

32. List five common glucocorticoids.
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Slow - limited by half lives of clotting factors
Methicillin - Nafcillin - and Dicloxacillin
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

33. MOA: Block protein synthesis at 30s subunit
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Disulfiram - like reaction with EtOH - Headache
Indomethacin is used to close a patent ductus arteriosus.
Aminoglycosides - Tetracyclines

34. Spironolactone - mechanism?
Succinylcholine
competitive inhibirot of aldosterone in the cortical collecting tubule
Aplastic anemia (dose independent) - Gray Baby Syndrome
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

35. What is the mechanism of action of Acetaminophen?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
prevention of nodal arrhythmias (SVT)
thick ascending limb

36. For Warfarin What is the Mechanism of action
Does not cross
Impairs the synthesis of vitamin K- dependent clotting factors
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

37. What type of patient should not take Misoprostol and why?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Because they require some residual islet function.

38. How would you treat African Trypanosomiasis (sleeping sickness)?
Suramin
Potent immunosuppressive used in organ transplant recipients.
- Tetracycline - amiodarone - sulfonamides
Ganciclovir is more toxic to host enzymes

39. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
No - hemicholinum block the uptake of Choline and thus Ach synthesis
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Inhalational general anesthetic.
troponin - tropomyosin system

40. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Long.
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)

41. Name three calcium channel blockers?
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Nifedipine - Verapamil - Diltiazem
Lidocaine - Mexiletine - Tocainide
- Alkalinize urine & dialysis

42. What is the category of drug names ending in - azol (e.g. Ketoconazole)
torsade de pointes
Succinylcholine
Antifungal.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

43. What is the mechanism of action of Clomiphene?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Ataxia - Dizziness - Slurred speech
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.

44. Antiarrhythmic class IV- primary site of action?
dry mouth - sedation - severe rebound hypertension
AV nodal cells
- Antipsychotics
Oral

45. What is action of insulin in the liver - in muscle - and in adipose tissue?
- Clindamycin
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.
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

46. What is the category of drug names ending in - ane (e.g. Halothane)
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Headache - flushing - dyspepsia - blue - green color vision.
Inhalational general anesthetic.

47. Bretyllium - toxicity?
new arrhythmias - hypotension
- Aminocaproic acid
Liver
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.

48. What is the category and mechanism of action of Zileuton in Asthma treatment?
Antileukotriene; blocks synthesis by lipoxygenase.
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Liver
Yes - it does not cross the placenta.

49. For Warfarin What is the Route of administration
Oral
Paranteral (IV - SC)
proarrhythmic
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness

50. Which drug(s) cause this reaction: Atropine - like side effects?
- Tricyclic antidepressants
distal convoluted tubule (early)
blocks SR Ca2+ channels
Megaloblastic anemia - Leukopenia - Granulocytopenia