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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 is the clinical utility of cocaine?
For serious - Gram + multidrug - resistant organisms
Cardiac glycoside (inotropic agent).
Local anesthetic.
The only local anesthetic with vasoconstrictive properties.

2. Name three Antiarrhythmic drugs in class IV.
Verapamil - Diltiazem - Bepridil
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
HTN - CHF - calcium stone formation - nephrogenic DI.
Carbenicillin - Piperacillin - and Ticarcillin

3. Which of epi - norepi - or isoproterenol results in bradycardia?
Neutropenia
- Disulfram & also sulfonylureas - metronidazole
Delirium - Tremor - Nephrotoxicity
Norepinephrine

4. What is the MOA for Acyclovir?
Cilastatin
check PFTs - LFTs - and TFTs
Choline acetyltransferase
Inhibit viral DNA polymerase

5. Dobutamine used for the tx of shock acts on Which receptors
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Beta1 more than B2

6. Which individuals are predisposed to Sulfonamide - induced hemolysis?
Nitrates
Spironolactone - Triamterene - Amiloride (the K+ STAys)
G6PD deficient individuals
CMV Retinitis in IC pts When Ganciclovir fails

7. How is Ganciclovir activated?
Neurotoxicity - Acute renal tubular necrosis
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Phosphorylation by a Viral Kinase
Tricyclic antidepressant.

8. Which drug(s) cause this reaction: P450 inhibition(6)?
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
Indomethacin is used to close a patent ductus arteriosus.

9. Side effects of Isoniazid (INH)?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Gram + cocci - Gram - rods - and Anerobes
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

10. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Ipratropium
- Isoniazid

11. What is treated with Chloroquine - Quinine - Mefloquine?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
Malaria (P. falciparum)
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Antibiotic - protein synthesis inhibitor.

12. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
- Steroids - Tamoxifen
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
atropine - homatropine - tropicamide
CMV - esp in Immunocompromised patients

13. What are common toxicities related to Vancomycin therapy?

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14. Adverse effects of Hydralazine?
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
block Na+ channels in the cortical collecting tubule
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
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.

15. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
- Daunorubicin & Doxorubicin
anticholinesterase glaucoma
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Norepinephrine

16. What would be the effect on blood pressure with infusion of the alpha -2 agonist clonidine?
Phenothiazine (neuroleptic - antiemetic).
Inhibits Viral DNA polymerase
Inhibition of 50S peptidyl transferase - Bacteriostatic
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

17. What is the MOA of Polymyxins?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
pulmonary edema - dehydration
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB

18. Loop diuretics (furosemide)- site of action?
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
thick ascending limb

19. Oral Penicillin
Same as penicillin. Extended spectrum antibiotics
Alpha -1 antagonist
Penicillin - V
- Act on same receptor - Full has greater efficacy

20. List the specific antidote for this toxin: Heparin
cholestyramine - colestipol
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
- Protamine
Treatment of infertility.

21. What beta 2 agonist will help your 21yo Astma pt?
Albuterol - tertbutaline
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Beta - lactamase cleavage of Beta - lactam ring
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.

22. How is Vancomycin used clinically?
Triple sulfas or SMZ
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
For serious - Gram + multidrug - resistant organisms
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.

23. Name several common Macrolides (3)
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Erythromycin - Azithromycin - Clarithromycin
Choline acetyltransferase
very short acting

24. What is the mechanism of action of Sildenafil (Viagra)?
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Buy AT 30 - CELL at 50'
-100% oxygen - hyperbaric
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

25. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Babiturate.
ACIDazolamide' causes acidosis
sedation - depression - nasal stuffiness - diarrhea

26. List the specific antidote for this toxin: Copper
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Methicillin - Nafcillin - and Dicloxacillin
- Penicillamine
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

27. How is Trimethoprim used clinically?
Peptic ulcer disease.
Used in combination therapy with SMZ to sequentially block folate synthesis
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.

28. How would you treat African Trypanosomiasis (sleeping sickness)?
Suramin
Long.
Triple sulfas or SMZ
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

29. Name two classes of drugs for HIV therapy
Protease Inhibitors and Reverse Transcriptase Inhibitors
Pseudomonas species and Gram - rods
competitive inhibirot of aldosterone in the cortical collecting tubule
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

30. Where does Griseofulvin deposit?
RESPIre
Keratin containing tissues - e.g. - nails
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

31. How is Leishmaniasis treated?
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Pentavalent Antimony
Short.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism

32. List the mechanism - clinical use - & toxicity of Doxorubicin.

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33. What are toxicities associated with Chloramphenicol?
Dopamine
Aplastic anemia (dose independent) - Gray Baby Syndrome
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
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.

34. For Heparin What is the Route of administration
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Paranteral (IV - SC)
sedation - sleep alterations
Beta - lactamase cleavage of Beta - lactam ring

35. Ibutilide - toxicity?
torsade de pointes
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
blocks SR Ca2+ channels
edrophonium (extremely short acting anticholinesterase)

36. What is a possible result of overdose of Acetaminophen?
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Due to the presence of a bulkier R group
- Niacin - Ca++ channel blockers - adenosine - vancomycin

37. Antimicrobial prophylaxis for Meningococcal infection
Rifampin (DOC) - minocycline
Lidocaine - Mexiletine - Tocainide
Gram + and Anerobes
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

38. Adenosine - clinical use?
Systemic mycoses
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
DOC in diagnosing and abolishing AV nodal arrhythmias

39. What is Niclosamide used for?
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Protease inhibitor.
Decreases synthesis of Mycolic Acid
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis

40. Which cancer drugs inhibit nucleotide synthesis(3)?
Epinephirine(Alpha1 -2 and Beta 1 -2)
- Methotrexate - 5 FU - 6 mercaptopurine
aPTT (intrinsic pathway)
- Clindamycin

41. Resistance mechanisms for Vancomycin
not a sulfonamide - but action is the same as furosemide
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
- ED 50 is less than the Km (less than 50% of receptors)
Penicillin - V

42. Which diuretics decrease urine Ca2+?
thiazides - amiloride
Acetylcholinesterase; ACh is broken down into choline and acetate.
Clavulanic acid
Anaerobes

43. What is the mechanism of Leuprolide?
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
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

44. Name common Polymyxins
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
TCA
Polymyxin B - Polymyxin E
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

45. List the specific antidote for this toxin: Cyanide
Diarrhea
dizziness - flushing - constipation (verapamil) - nausea
Nucleosides
- Nitrate - hydroxocobalamin thiosulfate

46. What are the clinical indications for bethanechol?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
No
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

47. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
Short.

48. Adverse effects of Captopril?
Potent immunosuppressive used in organ transplant recipients.
Local anesthetic.
- Ammonium Chloride
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

49. MOA: Block peptidoglycan synthesis
Bacitracin - Vancomycin
- Oxalic acid - Acidosis & nephrotoxicity
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).

50. ___________ are Teratogenic
Aminoglycosides
Disulfiram - like reaction with EtOH - Headache
TMP- SMZ (DOC) - aerosolized pentamidine
Non - Nucleosides