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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. What populations are Floroquinolones contraindicated in? Why?
ACIDazolamide' causes acidosis
Pregnant women - Children; because animal studies show Damage to Cartilage
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

2. What class of drug is echothiophate? What is its indication?
Ataxia - Dizziness - Slurred speech
Sildenafil fills the penis
anticholinesterase glaucoma
DHPG (dihydroxy-2- propoxymethyl guanine)

3. Antiarrhythmic class IC- effects?
Flecainide - Encainide - Propafenone
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.

4. What is the definition of zero - order kinetics? Example?
cardiac depression - peripheral edema - flushing - dizziness - constipation
Cardiac glycoside (inotropic agent).
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

5. How does a noncompetitive antagonist effect an agonist?
physostigmine
GI disturbances.
With supplemental Folic Acid
- Shifts the curve down - reduces Vmax

6. Adverse effects of Reserpine?
sedation - depression - nasal stuffiness - diarrhea
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)
Phenothiazine (neuroleptic - antiemetic).
No - it inhibits the release of Nor Epi

7. What is the mechanism of action of Allopurinol used to treat chronic gout?
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
sedation - positive Coombs' test
- Clindamycin

8. What is the mechanism of action of Misoprostol?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
- Phenytoin
Aminoglycosides - Tetracyclines
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

9. Which antimicrobial classes inhibit protein synthesis at the 30S subunit? (2)
atropine - homatropine - tropicamide
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
- Shifts the curve to the right - increases Km
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

10. Furosemide increases the excretion of What ion?
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Ca2+ (Loops Lose calcium)

11. What is the mechanism of action of NSAIDs other than Aspirin?
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Rapid (seconds)
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- Aminocaproic acid

12. What are common side effects of Amphotericin B?
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Pregnant women - Children; because animal studies show Damage to Cartilage
NO
Choline acetyltransferase

13. Name three ACE inhibitors?
Captopril - Enalapril - Lisinopril
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
Pituitary hormone.
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome

14. What is Imipenem always administered with?
CMV - esp in Immunocompromised patients
Prophylaxis for Influenza A - Rubella; Parkinson's disease
Cilastatin
VACUUM your Bed Room'

15. How does a competitive antagonist effect an agonist?
- Shifts the curve to the right - increases Km
Mebendazole/Thiabendazole - Pyrantel Pamoate
- B51Naloxone / naltrexone (Narcan)
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )

16. What antimuscarinic agent is used in asthma and COPD?
Chronic anticoagulation.
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
- Chlorpromazine - thioridazine - haloperidol
Ipratropium

17. What organisms does Griseofulvin target?
Beta lactams - inhibit cell wall synthesis - Bactericidal
bradycardia - AV block - CHF
Dermatophytes (tinea - ringworm)
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

18. Thiazides - site of action?
distal convoluted tubule (early)
Tricyclic antidepressant.
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.
No - warfarin - unlike heparin - can cross the placenta.

19. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
Ganciclovir is more toxic to host enzymes

20. What do Aminoglycosides require for uptake?
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Digitoxin 168hrs Digoxin 40 hrs
Oxygen
Succinylcholine

21. Describe Phase I metabolism in liver(3)?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
proximal convoluted tubule - thin descending limb - and collecting duct
Aminoglycosides - Tetracyclines
Gram + cocci - Gram - rods - and Anerobes

22. What is the category of drug names ending in - tidine (e.g. Cimetidine)
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
Useful in muscle paralysis during surgery or mechanical ventilation.
H2 antagonist
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

23. Adverse effects of Hydralazine?
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
- Disulfram & also sulfonylureas - metronidazole
Systemic mycoses

24. Which drug(s) cause this reaction: P450 inhibition(6)?
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides
TMP- SMZ (DOC) - aerosolized pentamidine
scopolamine
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

25. How do you treat coma in the ER (4)?
Buy AT 30 - CELL at 50'
Delirium - Tremor - Nephrotoxicity
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

26. Name some common Tetracyclines (4)
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Nifedipine - Verapamil - Diltiazem
Beta lactams - inhibit cell wall synthesis - Bactericidal

27. Which drug(s) cause this reaction: Thrombotic complications?
Beta -2 agonist.
G6PD deficient individuals
- Oral Contraceptives
Gram + and Anerobes

28. What is the mechanism of action of Omeprazole - Lansoprazole?
hypertension - angina - arrhythmias
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
Dermatophytes (tinea - ringworm)
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

29. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
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.
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Prevents the release of Ca from SR of skeletal muscle
Dopamine

30. Resistance mechanisms for Cephalosporins/Penicillins
Beta - lactamase cleavage of Beta - lactam ring
Ganciclovir is more toxic to host enzymes
It inhibits release of NE.
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.

31. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
Digoxin=urinary Digitoxin=biliary
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.)
Beta - lactam antibiotics
Binds to the Pyrophosphate Binding Site of the enzyme

32. For Heparin What is the Mechanism of action
Hypersensitivity reactions
all of them
Indomethacin is used to close a patent ductus arteriosus.
Activates antithrombin III

33. What is the category of drug names ending in - ipramine (e.g. Imipramine)
- Corticosteroids - heparin
Ibuprofen - Naproxen - and Indomethacin
Tricyclic antidepressant.
- Alkalate DNA - Brain tumors - CNS toxicity

34. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Lidocaine - Mexiletine - Tocainide
Epinephirine(Alpha1 -2 and Beta 1 -2)
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
Digitoxin 70% Digoxin 20-40%

35. What is the mechanism of Leuprolide?
Succinylcholine
Antileukotriene; blocks leukotriene receptors.
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
compensatory tachycardia - fluid retention - lupus - like syndrome

36. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
No - hemicholinum block the uptake of Choline and thus Ach synthesis
physostigmine

37. Which drug(s) cause this reaction: Cutaneous flushing (4)?
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
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.
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Same as penicillin. Extended spectrum antibiotics

38. Side effects of Isoniazid (INH)?
- Daunorubicin & Doxorubicin
- Chlorpromazine - thioridazine - haloperidol
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

39. What microorganisms are Aminoglycosides ineffective against?
Rare.
Primaquine
Anaerobes
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)

40. Ca2+ channel blockers - mechanism?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
very short acting
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

41. List the specific antidote for this toxin: Warfarin
Abortifacient.
Same as penicillin. Extended spectrum antibiotics
- Vitamin K & fresh frozen plasma
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

42. Is resistant to penicillinase?
- B51Naloxone / naltrexone (Narcan)
ACIDazolamide' causes acidosis
Gemfibrozil - Clofibrate
Imipenem

43. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
scopolamine
Epinephirine(Alpha1 -2 and Beta 1 -2)
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

44. What is the MOA of Griseofulvin?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Interferes with microtubule function - disrupts mitosis - inhibits growth
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

45. What is the loading dose formula?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Oral treatment of superficial infections
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
competitive inhibirot of aldosterone in the cortical collecting tubule

46. Which diuretics increase urine Ca2+?
is resistant
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
loop diuretics - spironolactone
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation

47. What type of gout is treated with Probenacid?
Chronic gout.
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Methylxanthine.
Epinephrine

48. What is the clinical use for Ampicillin and Amoxicillin?
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
1. Renal damage 2. Aplastic anemia 3. GI distress

49. Mannitol - site of action?
CMV - esp in Immunocompromised patients
proximal convoluted tubule - thin descending limb - and collecting duct
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

50. Why would dopamine be useful in treating shock?
Sulfonamides - Trimethoprim
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
Antileukotriene; blocks synthesis by lipoxygenase.
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.