Test your basic knowledge |

USMLE Step 1 Pharmacology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. If a patient is given hexamethonium - What would happen to his/her heart rate?
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Captopril - Enalapril - Lisinopril
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.

2. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Same as penicillin. Extended spectrum antibiotics
Heparin catalyzes the activation of antithrombin III.
CMV Retinitis in IC pts When Ganciclovir fails

3. What are the clinical uses for Ticlopidine - Clopidogrel?
Long.
Rifampin (DOC) - minocycline
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Succinylcholine

4. What is the clinical use of Mifepristone (RU486)?
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Acts as a wide spectrum carbapenem
CMV Retinitis in IC pts When Ganciclovir fails
Abortifacient.

5. Would blockade of muscarininc receptors in the bladder be useful in treating urinary retention?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Mg = Must go to the bathroom.
reversible SLE- like syndrome

6. What is the category - desired effect - and possible mechanism of Theophylline in treating Asthma?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Severe Gram - rod infections.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
IV vitamin K and fresh frozen plasma

7. Name the common Nucleoside Reverse Transcriptase Inhibitors
Digitoxin>95% Digoxin 75%
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)

8. Ca2+ sensitizers'- site of action?
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.
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Interferes with microtubule function - disrupts mitosis - inhibits growth
troponin - tropomyosin system

9. Name some common Sulfonamides (4)
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

10. Which individuals are predisposed to Sulfonamide - induced hemolysis?
ACE inhibitor.
Lipoxygenase
G6PD deficient individuals
Minor hepatotoxicity - Drug interactions (activates P450)

11. Antiarrhythmic class IV- toxicity?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
GI discomfort
1. Antiandrogen 2. Nausea 3. Vomiting
Blocks Norepi - but not Dopamine

12. What are the products and their toxicities of the metabolism of ethanol by / alcohol dehydrogenase?
Hypersensitivity reactions
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Erectile dysfunction.
Hypersensitivity reactions

13. What is the definition of zero - order kinetics? Example?
Verapamil - Diltiazem - Bepridil
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
CMV Retinitis in IC pts When Ganciclovir fails
IV vitamin K and fresh frozen plasma

14. What are four clinical activities of Aspirin?
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Megaloblastic anemia - Leukopenia - Granulocytopenia
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.

15. Which drug(s) cause this reaction: Cinchonism (2)?
- Quinidine - quinine
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Cephalosporins

16. For Warfarin What is the Route of administration
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
Oral

17. What effect would atropine have on a patient with peptic ulcer disease?
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Rare.
Gemfibrozil - Clofibrate
Give an antichloinesterase - neostigmine - edrophonium - etc

18. What is the clinical utility of clonidine?
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
Buy AT 30 - CELL at 50'

19. Preferential action of the Ca2+ channel blockers at vascular smooth muscle?
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Indirect agonist - uptake inhibitor
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
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. What enzyme does Zileuton inhibit?
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Lipoxygenase

21. What is the clinical use for Ampicillin and Amoxicillin?
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Sotalol - Ibutilide - Bretylium - Amiodarone

22. What are the clinical uses for 2nd Generation Cephalosporins?
GI disturbances.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Gram + - Gram - - Norcardia - Chlamydia

23. Ca2+ channel blockers - toxicity?
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
bradycardia - AV block - CHF
Oxygen
cardiac depression - peripheral edema - flushing - dizziness - constipation

24. What is the clinical use for Nystatin?
Paranteral (IV - SC)
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Topical and Oral - for Oral Candidiasis (Thrush)
Cyclooxygenases (COX I - COX II).

25. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
- Penicillin
Pseudomonas species and Gram - rods
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

26. Sotalol - toxicity?
- Tetracycline - amiodarone - sulfonamides
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
torsade de pointes - excessive Beta block
- Ammonium Chloride

27. How is Amantadine used clinically?

28. What cholinomimetic is useful in the diagnosis of Myasthenia Gravis
Edrophonium
Fast vs. Slow Acetylators
Acute (hours)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk

29. MOA: Block peptidoglycan synthesis
Bacitracin - Vancomycin
Keratin containing tissues - e.g. - nails
reversible SLE- like syndrome
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

30. Which drug(s) cause this reaction: Gray baby syndrome?
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Protamine sulfate
Increase target cell response to insulin.
- Chloramphenicol

31. Which diuretics cause alkalosis?
Phenothiazine (neuroleptic - antiemetic).
AluMINIMUM amount of feces.
loop diuretics - thiazides
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

32. What is the MOA for Clindamycin?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Gemfibrozil - Clofibrate

33. MOA: Block nucleotide synthesis
- Disulfram & also sulfonylureas - metronidazole
TMP- SMZ
Sulfonamides - Trimethoprim
It inhibits release of NE.

34. Name the common Azoles
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
BM suppression (neutropenia - anemia) - Peripheral neuropathy
proarrhythmic

35. What is the MOA for Trimethoprim (TMP)?
- Dimercaprol - succimer
VACUUM your Bed Room'
anticholinesterase glaucoma
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

36. List the specific antidote for this toxin: Salicylates
- Alkalinize urine & dialysis
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Peptic ulcer disease.
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

37. Which drug(s) cause this reaction: Agranulocytosis (3)?
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Beta adrenergic receptors and Ca2+ channels (stimulatory)
H2 antagonist
- Cloazapine - carbamazapine - colchicine - PTU

38. What is the effect of epinephrine infusion on bp and pulse pressure?
Cyclooxygenases (COX I - COX II).
Hydralazine and Minoxidil
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

39. What antimicrobial class is Aztreonam syngergestic with?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
No - warfarin - unlike heparin - can cross the placenta.
Aminoglycosides
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

40. What is the MOA for Metronidazole?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium
Forms toxic metabolites in the bacterial cell - Bactericidal

41. What is the category of drug names ending in - olol (e.g. Propranolol)
Rifampin
- aminoglycosides - loop diuretics - cisplatin
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Beta antagonist.

42. Which diuretics increase urine NaCl?
cross - allergenic
all of them
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
carbonic anhydrase inhibitors - K+ sparing diuretics

43. What are three types of antacids and the problems that can result from their overuse?
Acetylcholine esterase
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.

44. Resistance mechanisms for Cephalosporins/Penicillins
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Beta - lactamase cleavage of Beta - lactam ring
Gram + cocci - Gram - rods - and Anerobes
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

45. Name some common Tetracyclines (4)
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Penicillin.
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Gram + and Anerobes

46. Which drug(s) cause this reaction: Hepatitis?
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Blood
- Isoniazid

47. List the specific antidote for this toxin: Copper
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Amphotericin B - Nystatin - Fluconazole/azoles
- Penicillamine

48. Esmolol - short or long acting?
It acts presynaptically to increase NE release.
Only in limited amounts
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
very short acting

49. Which cancer drugs work at the level of mRNA(2)?
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
- Steroids - Tamoxifen
Mg = Must go to the bathroom.

50. What is the MOA of Ganciclovir?
dry mouth - sedation - severe rebound hypertension
Keratin containing tissues - e.g. - nails
- Glucagon
Inhibits CMV DNA polymerase