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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. Name two classes of drugs for HIV therapy
- Haloperidol - chlorpromazine - reserpine - MPTP
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Protease Inhibitors and Reverse Transcriptase Inhibitors
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

2. As an Anes you want to use a depolarizing neuromuscular blocking drug on your pt - What do you use
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Succinylcholine

3. What are common toxic side effects of Sulfonamides? (5)
Succinylcholine
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
- Atropine & pralidoxime
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

4. Name the common Aminoglycosides (5)
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
Interstitial nephritis
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

5. Classes of antihypertensive drugs?
thiazides - amiloride
Gemfibrozil - Clofibrate
- Oral Contraceptives
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

6. What is the category and mechanism of action of Zafirlukast in Asthma treatment?
aPTT (intrinsic pathway)
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Cyclooxygenases (COX I - COX II).
Antileukotriene; blocks leukotriene receptors.

7. How does NE modulate its own release? What other neurotransmitter has this same effect?
for RSV
Neomycin
prevention of nodal arrhythmias (SVT)
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.

8. Why would dopamine be useful in treating shock?
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
GI discomfort
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

9. MOA: Disrupt bacterial/fungal cell membranes
Prevents the release of Ca from SR of skeletal muscle
Polymyxins
Penicillin - G
Tricyclic antidepressant.

10. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
Gram + - Gram - - Norcardia - Chlamydia
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

11. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
Useful in muscle paralysis during surgery or mechanical ventilation.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)

12. What is the MOA of Aztreonam?
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Mg = Must go to the bathroom.
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
compensatory tachycardia - fluid retention - lupus - like syndrome

13. For Warfarin What is the Ability to inhibit coagulation in vitro
No
- Quinidine - quinine
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

14. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
- Ammonium Chloride
Praziquantel
- Steroids - Tamoxifen
Neomycin

15. K+- clinical use?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
depresses ectopic pacemakers - especially in digoxin toxicity
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Cephalosporin: 1) has a 6 member ring attached to the Beta lactam instead of a 5 member ring 2)has an extra functional group ( attached to the 6 member ring)

16. For Warfarin What is the Structure
Local anesthetic.
Small lipid - soluble molecule
Mebendazole/Thiabendazole - Pyrantel Pamoate
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

17. Your patient wants an effective drug to treat his motion sickness - What would you prescribe
CL= (rate of elimination of drug/ Plasma drug conc.)
- Antipsychotics
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Scopolamine

18. How is Ganciclovir used clinically?
Lipoxygenase
- Shifts the curve to the right - increases Km
CMV - esp in Immunocompromised patients
Diuresis in pateints with sulfa allergy

19. List the specific antidote for this toxin: Antimuscarinic (anticholinergic)
Inhibition of 50S peptidyl transferase - Bacteriostatic
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
- Physostigmine salicylate
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria

20. Which of these three drugs will cause a reflex bradycardia in your pt (Norepi - Epi - or Isoporterenol)
Norepinephrine
sedation - positive Coombs' test
Buy AT 30 - CELL at 50'
CMV - esp in Immunocompromised patients

21. Name four Antiarrhythmic drugs in class IA.
Penicillin - V
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Same as penicillin. Act as narrow spectrum antibiotics
Quinidine - Amiodarone - Procainamide - Disopyramide

22. What is the category of drug names ending in - caine (e.g. Lidocaine)
Local anesthetic.
Activates antithrombin III
- Antipsychotics
Competitive inibitor of progestins at progesterone receptors.

23. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
- Penicillin

24. Which cancer drugs inhibit nucleotide synthesis(3)?
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
- Methotrexate - 5 FU - 6 mercaptopurine
local anesthetic. CNS stimulation or depression. CV depression.
toxic

25. List the mechanism - clinical use - & toxicity of Methotrexate.
- Formaldehyde & formic acid - severe acidosis & retinal damage
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Slow - limited by half lives of clotting factors

26. How does resistance to Vancomycin occur?
sedation - positive Coombs' test
With an amino acid change of D- ala D- ala to D- ala D- lac
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
hypertension - angina - arrhythmias

27. List the mechanism - clinical use - & toxicity of 5 FU.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
- Corticosteroids - heparin
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

28. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
- Disulfram & also sulfonylureas - metronidazole
torsade de pointes - excessive Beta block
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
aPTT (intrinsic pathway)

29. What is the MOA for Rifampin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Inhibits DNA dependent RNA polymerase
Delirium - Tremor - Nephrotoxicity
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

30. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
- Formaldehyde & formic acid - severe acidosis & retinal damage
prevention of nodal arrhythmias (SVT)
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

31. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
proarrhythmic
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Pituitary hormone.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

32. List the specific antidote for this toxin: Anticholinesterases (organophosphate.)
TMP- SMZ (DOC) - aerosolized pentamidine
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
- Atropine & pralidoxime

33. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Pseudomonas species and Gram - rods
Benzodiazepine.
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

34. What is a sign of toxicity with the use of thrombolytics?
TCA
Carbenicillin - Piperacillin - and Ticarcillin
Bleeding.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).

35. What is the major side effect for Ampicillin and Amoxicillin?
Hypersensitivity reactions
sedation - depression - nasal stuffiness - diarrhea
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Inhibits Viral DNA polymerase

36. Isopoterenol was given to a patient with a developing AV block - why?
Succinylcholine
Stimulates beta adrenergic receptors
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'

37. What is the clinical use of Mifepristone (RU486)?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Abortifacient.
Epinephrine

38. What is the MOA for the Tetracyclines?
Those patients who are taking nitrates.
Give an antichloinesterase - neostigmine - edrophonium - etc
Hypersensitivity reactions
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

39. What are three complications of Warfarin usage?
Methicillin - Nafcillin - and Dicloxacillin
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

40. What are four advantages of newer low - molecular - weight heparins (Enoxaparin)?
RESPIre
Reversible block of histamine H2 receptors
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

41. How do we stop angina?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
- NaHCO3
Methicillin - Nafcillin - and Dicloxacillin

42. Which Tetracycline is used in patients with renal failure? / Why?
Acute gout.
Doxycycline - because it is fecally eliminated
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
- Isoniazid

43. What is Niclosamide used for?
Quinidine - Amiodarone - Procainamide - Disopyramide
- Cloazapine - carbamazapine - colchicine - PTU
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
No - it inhibits the release of Nor Epi

44. For Heparin What is the Ability to inhibit coagulation in vitro
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Yes
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Intrathecally

45. List the specific antidote for this toxin: Methanol & Ethylene glycol
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Pituitary hormone.
Useful in muscle paralysis during surgery or mechanical ventilation.
- Ethanol - dialysis - & fomepizole

46. What is the mechanism of action of the glucocorticoids?
Give an antichloinesterase - neostigmine - edrophonium - etc
Sotalol - Ibutilide - Bretylium - Amiodarone
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.

47. Mannitol - toxicity?
Digoxin=urinary Digitoxin=biliary
Flecainide - Encainide - Propafenone
pulmonary edema - dehydration
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

48. What is a possible result of overdose of Acetaminophen?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
not a sulfonamide - but action is the same as furosemide
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

49. List the specific antidote for this toxin: Heparin
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
cyanide toxicity (releases CN)
- Oxalic acid - Acidosis & nephrotoxicity
- Protamine

50. Antimicrobial prophylaxis for a history of recurrent UTIs
Alpha -1 antagonist
TMP- SMZ
Pralidoxime regenerates active cholinesterase.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types