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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. Mannitol - clinical use?
- Niacin - Ca++ channel blockers - adenosine - vancomycin
sedation - depression - nasal stuffiness - diarrhea
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
loop diuretics - thiazides

2. What are the clinical indications for bethanechol?
It affects beta receptors equally and is used in AV heart block (rare).
Minor hepatotoxicity - Drug interactions (activates P450)
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Primaquine

3. What is the MOA for Amphotericin B?
- polymyxins
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
proarrhythmic

4. Oral Penicillin
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Oral treatment of superficial infections
Penicillin - V
Non - Nucleosides

5. What are four conditions in Which H2 Blockers are used clinically?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Cilastatin
Yes
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

6. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
It acts presynaptically to increase NE release.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
- Hydralazine - Procainamide - INH - phenytoin
Interferes with microtubule function - disrupts mitosis - inhibits growth

7. For Warfarin What is the Ability to inhibit coagulation in vitro
No
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
loop diuretics - spironolactone

8. Ca2+ channel blockers - clinical use?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Oral
Chronic gout.
hypertension - angina - arrhythmias

9. Amprotericin B ___________ the BBB
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
depresses ectopic pacemakers - especially in digoxin toxicity
Does not cross

10. What is the clinical utility of cocaine?
Intrathecally
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
The only local anesthetic with vasoconstrictive properties.

11. List the specific antidote for this toxin: Benzodiazepines
CMV - esp in Immunocompromised patients
Foscarnet = pyroFosphate analog
- Flumazenil
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.

12. Which of epi - norepi - or isoproterenol results in bradycardia?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
H2 antagonist
Norepinephrine
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

13. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
Dermatophytes (tinea - ringworm)
Antifungal.
- Chlorpromazine - thioridazine - haloperidol
Penicillin - G

14. What are Polymyxins used for?
Blocks Norepi - but not Dopamine
Resistant Gram - infections
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Amphotericin B - Nystatin - Fluconazole/azoles

15. Hydrochlorothiazide - clinical use?
Rash - Pseudomembranous colitis
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Acetylcholine esterase
HTN - CHF - calcium stone formation - nephrogenic DI.

16. What drug is used during the pregnancy of an HIV+ mother? - Why?
Interstitial nephritis
Pentamidine
AZT - to reduce risk of Fetal Transmission
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

17. What is combination TMP- SMZ used to treat?
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Nifedipine - Verapamil - Diltiazem
- Disulfram & also sulfonylureas - metronidazole
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

18. Toxicities associated with Acyclovir?
- EDTA - dimercaprol - succimer - & penicillamine
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Delirium - Tremor - Nephrotoxicity
Tricyclic antidepressant.

19. What is a Ribavirin toxicity?
Topical and Oral - for Oral Candidiasis (Thrush)
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
GI distress - Skin rash - and Seizures at high plasma levels
Hemolytic anemia

20. What is the MOA for the Azoles?
Hypersensitivity reactions
Fast vs. Slow Acetylators
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Inhibit Ergosterol synthesis

21. What is Fluconazole specifically used for?
For serious - Gram + multidrug - resistant organisms
- NaHCO3
Digitoxin 70% Digoxin 20-40%
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

22. What are the side effects of Rifampin?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Erectile dysfunction.
Minor hepatotoxicity - Drug interactions (activates P450)
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil

23. Antiarrhythmic class IC- toxicity?
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Epinephrine
- Oral Contraceptives
proarrhythmic

24. What additional side effects exist for Ampicillin?
Rash - Pseudomembranous colitis
- aminoglycosides - loop diuretics - cisplatin
TMP- SMZ (DOC) - aerosolized pentamidine
- Glucocorticoid withdrawal

25. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
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.
Inhibit viral DNA polymerase
Norepinephrine

26. What is the MOA for Rifampin?
Diarrhea
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Inhibits DNA dependent RNA polymerase
Beta - lactam antibiotics

27. Acetazolamide - mechanism?
Ataxia - Dizziness - Slurred speech
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Polymyxins
Oral treatment of superficial infections

28. Why is Cilastatin administered with Imipenem?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
toxic
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
- Nitrate - hydroxocobalamin thiosulfate

29. What is the clinical use for Heparin?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

30. Cautions When using Amiodarone?
check PFTs - LFTs - and TFTs
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
- Shifts the curve to the right - increases Km
Modification via Acetylation - Adenylation - or Phosphorylation

31. What is an acronym to remember Anti - TB drugs?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
RESPIre
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

32. How can the t1/2 of INH be altered?
Fast vs. Slow Acetylators
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Aplastic anemia (dose independent) - Gray Baby Syndrome
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes

33. What is the category of drug names ending in - olol (e.g. Propranolol)
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.)
blocks SR Ca2+ channels
Beta antagonist.
H2 antagonist

34. What are common side effects of RT Inhibitors?
G6PD deficient individuals
BM suppression (neutropenia - anemia) - Peripheral neuropathy
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.)
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).

35. Isopoterenol was given to a patient with a developing AV block - why?
Cell membrane Ca2+ channels of cardiac sarcomere
Stimulates beta adrenergic receptors
Sotalol - Ibutilide - Bretylium - Amiodarone
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.

36. Classes of antihypertensive drugs?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Quinidine - Amiodarone - Procainamide - Disopyramide
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

37. For Heparin What is the Duration of action
Acute (hours)
- Lithium
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

38. What are five possible toxic effects of Aspirin therapy?

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39. How are the HIV drugs used clinically?

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40. Beta Blockers - BP?
It affects beta receptors equally and is used in AV heart block (rare).
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
decrease

41. Antimicrobial prophylaxis for a history of recurrent UTIs
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
TMP- SMZ
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
GET on the Metro

42. Which drug(s) cause this reaction: P450 inhibition(6)?
- Haloperidol - chlorpromazine - reserpine - MPTP
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

43. Which drug(s) cause this reaction: Photosensitivity(3)?
- Tetracycline - amiodarone - sulfonamides
With an amino acid change of D- ala D- ala to D- ala D- lac
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Oral treatment of superficial infections

44. What is the most common cause of Pt noncompliance with Macrolides?
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
GI discomfort
torsade de pointes - excessive Beta block

45. Which drug(s) cause this reaction: Tubulointerstitial Nephritis (5)?
Paranteral (IV - SC)
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
- N- acetylcystine
Large anionic polymer - acidic

46. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
- Vitamin K & fresh frozen plasma
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities

47. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
AmOxicillin has greater Oral bioavailability
- Penicillin
Anaerobes
Those patients who are taking nitrates.

48. Adverse effects of Nifedipine - verapamil?
dizziness - flushing - constipation (verapamil) - nausea
Due to the presence of a bulkier R group
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Resistant Gram - infections

49. What are common toxicities associated with Tetracyclines?

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50. Explain potency in relation to full and partial agonists(2).
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Edrophonium
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.