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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 is the mechanism of action of the H2 Blockers?
- Tetracycline
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Fluoroquinolones
Reversible block of histamine H2 receptors

2. How can the toxic effects of TMP be ameliorated?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
With supplemental Folic Acid
- Corticosteroids - heparin
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)

3. Name the Protease Inhibitors (4)
Nitrates
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.

4. What are common toxicities associated with Tetracyclines?

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5. Which diuretics increase urine NaCl?
- Clindamycin
all of them
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
CMV Retinitis in IC pts When Ganciclovir fails

6. Name two classes of drugs for HIV therapy
Albuterol - tertbutaline
Protease Inhibitors and Reverse Transcriptase Inhibitors
Butyrophenone (neuroleptic).
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

7. Which drug(s) cause this reaction: Hot flashes?
- Tetracycline - amiodarone - sulfonamides
Bleeding.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
- Tamoxifen

8. What is Clindamycin used for clinically?
Bacitracin - Vancomycin
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

9. Acetazolamide - toxicity?
Dermatophytes (tinea - ringworm)
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins

10. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- Glucagon
Cyclooxygenases (COX I - COX II).

11. Resistance mechanisms for Chloramphenicol
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Inhibit viral DNA polymerase
Modification via Acetylation
Paranteral (IV - SC)

12. Why does NE result in bradycardia?
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Botulinum
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression

13. Antiarrhythmic class IB- toxicity?
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
local anesthetic. CNS stimulation or depression. CV depression.
Liver
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

14. Why is carbachol and pilocarpine useful in treatment of glaucoma?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Antileukotriene; blocks synthesis by lipoxygenase.
1. Acarbose 2. Miglitol

15. Name common Polymyxins
Polymyxin B - Polymyxin E
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Cilastatin
Albuterol - tertbutaline

16. Name two organisms Vancomycin is commonly used for?
Lidocaine - Mexiletine - Tocainide
- Phenytoin
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Diarrhea

17. What is the mechanism of action and clinical use of the antiandrogens Ketoconazole and Spironolactone?
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

18. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.

19. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Systemic mycoses
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)

20. Which Aminoglycoside is used for Bowel Surgery ?
Ceftriaxone
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Neomycin
Digoxin=urinary Digitoxin=biliary

21. A common side effects of Interferon (INF) treatment is?
Doxycycline - because it is fecally eliminated
Neutropenia
- Daunorubicin & Doxorubicin
cross - allergenic

22. What is the category of drug names ending in - cycline (e.g. Tetracycline)
Digitoxin 168hrs Digoxin 40 hrs
Used in combination therapy with SMZ to sequentially block folate synthesis
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Antibiotic - protein synthesis inhibitor.

23. What side effect of using atropine to induce pupillary dilation would you expect?
- Act on same receptor - Full has greater efficacy
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Chronic (weeks or months)
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

24. ADH antagonists - site of action?
torsade de pointes
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
With supplemental Folic Acid
collecting ducts

25. Which cancer drugs work at the level of proteins(2)?
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Hydralazine and Minoxidil
Captopril - Enalapril - Lisinopril

26. What are four thrombolytics?
Beta Blockers
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
- Chlorpromazine - thioridazine - haloperidol
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation

27. Which drug(s) cause this reaction: Thrombotic complications?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
These B-2 agonists cause respiratory smooth muscle to relax.
- Oral Contraceptives

28. What are three clinical uses of the NSAIDs?
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Rash - Pseudomembranous colitis

29. Reserpine will block the syntheis of this drug and but not its precursor.
Blocks Norepi - but not Dopamine
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Prophylaxis for Influenza A - Rubella; Parkinson's disease

30. What drug is given for Pneumocystis carinii prophylaxis?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Pentamidine
Clavulanic acid

31. What are Aminoglycosides synergistic with?
GI discomfort
Beta - lactam antibiotics
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)

32. What is the effect of the Glitazones in diabetes treatment?
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Amphetamine and Ephedrine
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.
Increase target cell response to insulin.

33. Which diuretics increase urine Ca2+?
- ACE inhibitors (Losartan>no cough)
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
check PFTs - LFTs - and TFTs
loop diuretics - spironolactone

34. List the mechanism - clinical use - & toxicity of Bleomycin.
collecting ducts
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
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.

35. Isopoterenol was given to a patient with a developing AV block - why?
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Beta1 more than B2
Stimulates beta adrenergic receptors
AV nodal cells

36. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
Hypersensitivity reactions
- Disulfram & also sulfonylureas - metronidazole
Long.
Antifungal.

37. What is the category - method of use - and adverse effects of Salmeterol in Asthma treatment?
Reversible block of histamine H2 receptors
Spironolactone - Triamterene - Amiloride (the K+ STAys)
aPTT (intrinsic pathway)
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

38. Describe Phase I metabolism in liver(3)?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
- Tetracycline - amiodarone - sulfonamides
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia

39. What is the chemical name for Ganciclovir?
Useful in muscle paralysis during surgery or mechanical ventilation.
DHPG (dihydroxy-2- propoxymethyl guanine)
Neurotoxicity - Acute renal tubular necrosis
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

40. Why is pyridostigmine effective in the treatment of myasthenia gravis?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Give an antichloinesterase - neostigmine - edrophonium - etc
Increase target cell response to insulin.

41. For Heparin What is the Onset of action
Rapid (seconds)
Cell membrane Ca2+ channels of cardiac sarcomere
Because they require some residual islet function.
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.

42. What is the MOA of Foscarnet?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Inhibits Viral DNA polymerase
scopolamine
fetal renal toxicity - hyperkalemia

43. For Heparin What is the Ability to inhibit coagulation in vitro
Yes
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
- Formaldehyde & formic acid - severe acidosis & retinal damage
VACUUM your Bed Room'

44. What are the side effects of Rifampin?
Nucleosides
Minor hepatotoxicity - Drug interactions (activates P450)
Blood
Anaerobes

45. List the specific antidote for this toxin: Methanol & Ethylene glycol
- Ethanol - dialysis - & fomepizole
For serious - Gram + multidrug - resistant organisms
Aminoglycosides
hypertension - angina - arrhythmias

46. How is Griseofulvin used clinically?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Beta -2 agonist.
Oral treatment of superficial infections
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

47. What is the category of drug names ending in - tidine (e.g. Cimetidine)
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
- Hydralazine - Procainamide - INH - phenytoin
H2 antagonist
Due to the presence of a bulkier R group

48. What type of gout is treated with Probenacid?
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Polymyxins
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Chronic gout.

49. Ryanodine - site of action?
- ACE inhibitors (Losartan>no cough)
blocks SR Ca2+ channels
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
- Ammonium Chloride

50. What type of patient should not take Misoprostol and why?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
decrease
Amphotericin B - Nystatin - Fluconazole/azoles
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.