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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. Decrease Digitoxin dose in renal failure?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
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.
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
NO

2. Which drug(s) cause this reaction: SLE- like syndrome?
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
- Hydralazine - Procainamide - INH - phenytoin
collecting ducts
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

3. How are Sulfonamides employed clinically?
Benzathine penicillin G
Gram + - Gram - - Norcardia - Chlamydia
Paranteral (IV - SC)
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

4. Adverse effects of Reserpine?
severe hypertension - CHF
sedation - depression - nasal stuffiness - diarrhea
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

5. Name the common Non - Nucleoside Reverse Transcriptase Inhibitors
- ACE inhibitors (Losartan>no cough)
Quinidine - Amiodarone - Procainamide - Disopyramide
Oxygen
Nevirapine - Delavirdine

6. What are two toxicities associated with Cyclosporine?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
blocks SR Ca2+ channels

7. Hydralazine - class and mechanism?
Beta antagonist.
Beta -2 agonist.
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

8. The COX-2 inhibitors (celecoxib - rofecoxib) have similar side effects to the NSAIDs with What one exception?
decrease
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Bleeding.

9. What is the MOA for Ampicillin and Amoxicillin?
Hypersensitivity reactions
AV nodal cells
AZT - to reduce risk of Fetal Transmission
Same as penicillin. Extended spectrum antibiotics

10. Antiarrhythmic class II- mechanism?
Heparin catalyzes the activation of antithrombin III.
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Act on same receptor - Full has greater efficacy
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux

11. List the specific antidote for this toxin: Amphetamine
- Chlorpromazine - thioridazine - haloperidol
- Ammonium Chloride
Reversible block of histamine H2 receptors
- Antipsychotics

12. Which drug(s) cause this reaction: Oto and Nephrotoxicity (3)?
- Dimercaprol - succimer
Teratogenic - Carcinogenic - Confusion - Headaches
very short acting
- aminoglycosides - loop diuretics - cisplatin

13. What are three unwanted effects of Mifepristone?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Sulfonamides - Trimethoprim
- Deferoxamine

14. Which drug(s) cause this reaction: Disulfram - like reaction (4) ?
Scopolamine
Choline acetyltransferase
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

15. What is the mecanism of action - effective period - and ineffective period of use for Cromolyn in treating Asthma?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Stimulates beta adrenergic receptors
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

16. What are common side effects of RT Inhibitors?
Saquinavir - Ritonavir - Indinavir - Nelfinavir
AZT - to reduce risk of Fetal Transmission
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
BM suppression (neutropenia - anemia) - Peripheral neuropathy

17. Which diuretics cause acidosis?
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
block Na+ channels in the cortical collecting tubule
carbonic anhydrase inhibitors - K+ sparing diuretics
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.

18. Name some common Tetracyclines (4)
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
reversible SLE- like syndrome
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Tetracycline - Doxycycline - Demeclocycline - Minocycline

19. K+ sparing diuretics - toxicity?
Gram + - Gram - - Norcardia - Chlamydia
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
- Haloperidol - chlorpromazine - reserpine - MPTP
Tricyclic antidepressant.

20. List the mechanism - clinical use - & toxicity of Cyclophosphamide.
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Inhibt Assembly of new virus by Blocking Protease Enzyme
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.

21. What are the clinical uses for Imipenem/cilastatin?
Gram + - Gram - - Norcardia - Chlamydia
Gram + cocci - Gram - rods - and Anerobes
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Antibiotic - protein synthesis inhibitor.

22. For Warfarin What is the Structure
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
- Alkalinize urine & dialysis
Penicillin.
Small lipid - soluble molecule

23. List the mechanism - clinical use - & toxicity of Paclitaxel.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Chronic (weeks or months)
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.

24. What is the most common cause of Pt noncompliance with Macrolides?
Alpha -1 antagonist
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Digitoxin>95% Digoxin 75%
GI discomfort

25. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
Pituitary hormone.
Staphlococcus aureus
Nevirapine - Delavirdine
Rifampin (DOC) - minocycline

26. What is the MOA for the Azoles?
Methylation of rRNA near Erythromycin's ribosome binding site
Inhibit Ergosterol synthesis
Those patients who are taking nitrates.
Inhibits cell wall mucopeptide formation - Bactericidal

27. 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.
Due to the presence of a bulkier R group
BM suppression (neutropenia - anemia) - Peripheral neuropathy
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

28. What is the loading dose formula?
- Penicillamine
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
severe hypertension - CHF
depresses ectopic pacemakers - especially in digoxin toxicity

29. Why are the Sulfonylureas inactive in IDDM (type -1)?
- Disulfram & also sulfonylureas - metronidazole
- Physostigmine salicylate
- Tetracycline
Because they require some residual islet function.

30. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Binding to the presynaptic alpha 2 release modulating receptors
Chronic gout.
Blocks Norepi - but not Dopamine
The PTT.

31. Which drug(s) cause this reaction: Gingival hyperplasia?
Only in limited amounts
Anaerobes
Systemic mycoses
- Phenytoin

32. What is a sign of toxicity with the use of thrombolytics?
Penicillin.
Used in combination therapy with SMZ to sequentially block folate synthesis
Bleeding.
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

33. The MOA for Chloramphenicol is?
1. Reliable (<1% failure) 2. Lowers risk of endometrial and ovarian cancer 3. Decreased incidence of ectopic pregnancy 4. Lower risk of pelvic infections 5. Regulation of menses
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Inhibition of 50S peptidyl transferase - Bacteriostatic
Constant FRACTION eliminated per unit time.(exponential)

34. What is the memory key for Isoniazid (INH) toxicity?
INH: Injures Neurons and Hepatocytes
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
Penicillin.
CMV Retinitis in IC pts When Ganciclovir fails

35. List five common glucocorticoids.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Topical and Oral - for Oral Candidiasis (Thrush)
- Shifts the curve down - reduces Vmax
Same as penicillin. Extended spectrum antibiotics

36. Triamterene and amiloride - mechanism?
- Deferoxamine
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
block Na+ channels in the cortical collecting tubule
Disulfiram - like reaction with EtOH - Headache

37. Ethacrynic Acid - mechanism?
- Oral Contraceptives
Rifampin
not a sulfonamide - but action is the same as furosemide
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

38. What drug is used to diagnose myasthenia gravis?
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Beta Blockers
edrophonium (extremely short acting anticholinesterase)
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids

39. What parasites are treated with Pyrantel Pamoate (more specific)?
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
Methylxanthine.
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Antibiotic - protein synthesis inhibitor.

40. List the mechanism - clinical use - & toxicity of Busulfan.
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Rifampin
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
troponin - tropomyosin system

41. Which receptors does phenylephrine act upon?
Norepinephrine
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
- Daunorubicin & Doxorubicin
Ceftriaxone

42. Name two organisms Vancomycin is commonly used for?
Benzathine penicillin G
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

43. What is the chemical name for Ganciclovir?
- Act on same receptor - Full has greater efficacy
- Alkalinize urine & dialysis
DHPG (dihydroxy-2- propoxymethyl guanine)
The PT.

44. What is the category of drug names ending in - azepam (e.g. Diazepam)
compensatory tachycardia - fluid retention - lupus - like syndrome
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.
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Benzodiazepine.

45. What is the major side effect for Ampicillin and Amoxicillin?
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Hypersensitivity reactions

46. Acetazolamide causes?

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47. What is the category of drug names ending in - phylline (e.g. Theophylline)
HTN - CHF - calcium stone formation - nephrogenic DI.
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Bethanechol - Neostigmine - physostigmine
Methylxanthine.

48. What is the MOA of Polymyxins?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
No - warfarin - unlike heparin - can cross the placenta.
Onchocerciasis ('river blindness'-- rIVER- mectin)
PT

49. What is Fluconazole specifically used for?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
- Disulfram & also sulfonylureas - metronidazole

50. For Warfarin What is the Route of administration
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Oral
Staphlococcus aureus