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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. Name the common Azoles
Mg = Must go to the bathroom.
Beta antagonist.
- Methotrexate - 5 FU - 6 mercaptopurine
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole

2. What is the clinical use of Mifepristone (RU486)?
Acetylcholine esterase
Abortifacient.
Quinolones
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

3. Name four Antiarrhythmic drugs in class III.
Nucleosides
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Sotalol - Ibutilide - Bretylium - Amiodarone
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

4. What is Clindamycin used for clinically?
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Cyclooxygenases (COX I - COX II).
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Chronic gout.

5. What is the clinical use for Nystatin?
Same as penicillin. Extended spectrum antibiotics
thick ascending limb
thiazides - amiloride
Topical and Oral - for Oral Candidiasis (Thrush)

6. List the specific antidote for this toxin: Cyanide
- Nitrate - hydroxocobalamin thiosulfate
hyperaldosteronism - K+ depletion - CHF
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Carbenicillin - Piperacillin - and Ticarcillin

7. Aztreonam is not usually...
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
toxic
Large anionic polymer - acidic
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.

8. Cocaine casues vasoconstriction and local anesthesia by What mechanism
Indirect agonist - uptake inhibitor
-100% oxygen - hyperbaric
AV nodal cells
Albuterol - tertbutaline

9. What is the only depolarizing neuromuscular blocking agent?
Digitoxin>95% Digoxin 75%
Succinylcholine
Pentamidine
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.

10. What are common toxicities associated with Macrolides? (4)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Prevents the release of Ca from SR of skeletal muscle
Protamine sulfate
Binding to the presynaptic alpha 2 release modulating receptors

11. How is Amantadine used clinically?

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12. List the mechanism - clinical use - & toxicity of Paclitaxel.
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Ataxia - Dizziness - Slurred speech
It affects beta receptors equally and is used in AV heart block (rare).

13. What are Fluoroquinolones indicated for? (3)
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- Shifts the curve down - reduces Vmax
Intrathecally
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

14. What are Polymyxins used for?
Resistant Gram - infections
anuria - CHF
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Prevention of NSAID- induced peptic ulcers - maintains a PDA.

15. For Warfarin What is the Structure
Diuresis in pateints with sulfa allergy
GI disturbances.
hyperaldosteronism - K+ depletion - CHF
Small lipid - soluble molecule

16. Spironolactone - mechanism?
The PTT.
competitive inhibirot of aldosterone in the cortical collecting tubule
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

17. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
proximal convoluted tubule - thin descending limb - and collecting duct
Polymyxins
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)

18. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
- Act on same receptor - Full has greater efficacy
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity

19. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
Beta - lactam antibiotics
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
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

20. What is are two clinical uses of Cyclosporine?
GI upset
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

21. Beta Blockers - CNS toxicity?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
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.
Interstitial nephritis
sedation - sleep alterations

22. Why would dopamine be useful in treating shock?
- Nitrate - hydroxocobalamin thiosulfate
Nephrotoxicity
Erectile dysfunction.
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

23. List the specific antidote for this toxin: Opioids
- Disulfram & also sulfonylureas - metronidazole
- B51Naloxone / naltrexone (Narcan)
blocks SR Ca2+ channels
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

24. What process does Zafirlukast interfere with?
- ACE inhibitors (Losartan>no cough)
Cephalosporins
Leukotrienes increasing bronchial tone.
DHPG (dihydroxy-2- propoxymethyl guanine)

25. Which cancer drugs work at the level of proteins(2)?
1. Pioglitazone 2. Rosiglitazone.
CMV - esp in Immunocompromised patients
Captopril - Enalapril - Lisinopril
- Vinca alkaloids(inhibit MT) - Paclitaxel

26. How is Acyclovir used clinically?
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
Stimulates beta adrenergic receptors
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

27. Which drug(s) cause this reaction: Agranulocytosis (3)?
- Cloazapine - carbamazapine - colchicine - PTU
Norepinephrine
TMP- SMZ
local anesthetic. CNS stimulation or depression. CV depression.

28. Antimicrobial prophylaxis for Meningococcal infection
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Rifampin (DOC) - minocycline
Epinephrine
pulmonary edema - dehydration

29. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
Hydralazine and Minoxidil
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
aPTT (intrinsic pathway)
Rifampin

30. While at a tail gait party - you bite into a sandwich that a yellow jacket is also enjoying. Knowing your allergy to this creature - What should you do?
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
sedation - sleep alterations
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Tamoxifen

31. What are the Macrolides used for clinically?
- Clindamycin
Cell membrane Ca2+ channels of cardiac sarcomere
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Interferes with microtubule function - disrupts mitosis - inhibits growth

32. Ethacrynic Acid - mechanism?
Epinephrine
Small lipid - soluble molecule
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
not a sulfonamide - but action is the same as furosemide

33. Common side effects associated with Clindamycin include?
- B51Naloxone / naltrexone (Narcan)
physostigmine
Pyridoxine (B6) administration
Pseudomembranous colitis (C. difficile) - fever - diarrhea

34. Which drug(s) cause this reaction: P450 induction(6)?
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
GI distress - Skin rash - and Seizures at high plasma levels

35. For Warfarin What is the Onset of action
Slow - limited by half lives of clotting factors
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
amphetamine and ephedrine
- Ethanol - dialysis - & fomepizole

36. Which cancer drugs work at the level of mRNA(2)?
Suramin
- Corticosteroids - heparin
- Steroids - Tamoxifen
Because they require some residual islet function.

37. ACE inhibitors - clinical use?
Chronic anticoagulation.
Same as penicillin. Extended spectrum antibiotics
hypertension - CHF - diabetic renal disease
Ipratropium

38. Which antimuscarinic agents are used in producing mydriasis and cycloplegia?
atropine - homatropine - tropicamide
Headache - flushing - dyspepsia - blue - green color vision.
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Liver

39. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
Dopamine; causes its release from intact nerve terminals
- Oxalic acid - Acidosis & nephrotoxicity
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic

40. Why is pyridostigmine effective in the treatment of myasthenia gravis?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Short.
local anesthetic. CNS stimulation or depression. CV depression.

41. What are the clinical uses for 2nd Generation Cephalosporins?
Rapid (seconds)
Norepinephrine
loop diuretics - thiazides
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

42. When is Rifampin not used in combination with other drugs?
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Gram + cocci - Gram - rods - and Anerobes
Bacitracin - Vancomycin
Only in limited amounts

43. MOA: Block protein synthesis at 30s subunit
- Daunorubicin & Doxorubicin
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Aminoglycosides - Tetracyclines
- Methotrexate - 5 FU - 6 mercaptopurine

44. What type of gout is treated with Allopurinol?
- Ethanol - dialysis - & fomepizole
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
- Clindamycin
Chronic gout.

45. How does resistance to Vancomycin occur?
Norepinephrine (Alpha1 -2 and beta 1)
With an amino acid change of D- ala D- ala to D- ala D- lac
Nephrotoxicity
Norepinephrine

46. What parasitic condition is treated with Ivermectin?

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47. Which cancer drugs inhibit nucleotide synthesis(3)?
- Methotrexate - 5 FU - 6 mercaptopurine
decrease conduction velocity - increase ERP - increase PR interval
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Protease Inhibitors and Reverse Transcriptase Inhibitors

48. What cholinomimetic is useful in the diagnosis of Myasthenia Gravis
Same as penicillin. Extended spectrum antibiotics
Babiturate.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Edrophonium

49. Name some common Sulfonamides (4)
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
loop diuretics - spironolactone
Methicillin - Nafcillin - and Dicloxacillin
Premature infants - because they lack UDP- glucuronyl transferase

50. Steady state concentration is reached in __ number of half - lifes
Inhibits Viral DNA polymerase
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
Na/K ATPase