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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. Does Heparin have a long - medium - or short half life?
proximal convoluted tubule
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Short.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

2. What are two types of drugs that interfere with the action of Sucralfate and why?
No - it inhibits the release of Nor Epi
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Sotalol - Ibutilide - Bretylium - Amiodarone

3. List the specific antidote for this toxin: Methemoglobin
- Methylene blue
Mebendazole/Thiabendazole - Pyrantel Pamoate
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Inhibition of 50S peptidyl transferase - Bacteriostatic

4. Describe the MOA of Interferons (INF)
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
The PTT.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

5. If a patient is given hexamethonium - What would happen to his/her heart rate?
Premature infants - because they lack UDP- glucuronyl transferase
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
GI upset
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.

6. How would you reverse the effect of a neuromuscular blocking agent?
Acts as a wide spectrum carbapenem
Ataxia - Dizziness - Slurred speech
loop diuretics - spironolactone
Give an antichloinesterase - neostigmine - edrophonium - etc

7. What are three clinical uses of the Leuprolide?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- B51Naloxone / naltrexone (Narcan)
Beta lactams - inhibit cell wall synthesis - Bactericidal
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids

8. What type of gout is treated with Allopurinol?
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Aminoglycosides - Tetracyclines
Chronic gout.
Cryptococcal meningitis in AIDS patients and Candidal infections of all types

9. List five common glucocorticoids.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Activates antithrombin III
Carbenicillin - Piperacillin - and Ticarcillin
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone

10. Isopoterenol was given to a patient with a developing AV block - why?
Used in combination therapy with SMZ to sequentially block folate synthesis
Protamine sulfate
Stimulates beta adrenergic receptors
Neomycin

11. Which drug(s) cause this reaction: Torsade de pointes (2)?
TMP- SMZ
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

12. Why would you give a drug like pancuronium or succinylcholine?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Useful in muscle paralysis during surgery or mechanical ventilation.

13. List some specifics of lead poisoning(4)?
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Onchocerciasis ('river blindness'-- rIVER- mectin)
Blocks Influenza A and RubellA; causes problems with the cerebellA

14. What is the mechanism of action of the Sulfonylureas?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Nevirapine - Delavirdine

15. Which RT inhibitors cause a Rash?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Non - Nucleosides
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).

16. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
decrease conduction velocity - increase ERP - increase PR interval
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.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions

17. Mg+- clinical use?
Disulfiram - like reaction with EtOH - Headache
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
effective in torsade de pointes and digoxin toxicity

18. Which drug(s) cause this reaction: Diabetes insipidus?
Polymyxins
- Lithium
Non - Nucleosides
Diarrhea

19. For Heparin What is the Mechanism of action
physostigmine
Activates antithrombin III
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
NO

20. What is the clinical use for Penicillin?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
- Quinidine - quinine

21. Antimicrobial prophylaxis for Syphilis
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Hypersensitivity reactions
Dopamine; causes its release from intact nerve terminals
Benzathine penicillin G

22. Antiarrhythmic class IV- toxicity?
Blood
Those patients who are taking nitrates.
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Penicillin - G

23. For Heparin What is the Onset of action
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Rapid (seconds)
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Beta antagonist.

24. What enzyme is responsible for the breakdown of ACh in the synaptic cleft?
Acetylcholinesterase; ACh is broken down into choline and acetate.
INH: Injures Neurons and Hepatocytes
Minor hepatotoxicity - Drug interactions (activates P450)
- Steroids - Tamoxifen

25. What class of drug is echothiophate? What is its indication?
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
- Chlorpromazine - thioridazine - haloperidol
anticholinesterase glaucoma
torsade de pointes - excessive Beta block

26. When is Rifampin not used in combination with other drugs?
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Liver
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
viral kinase

27. What microorganisms are clinical indications for Tetracycline therapy?

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28. List the mechanism - clinical use - & toxicity of Prednisone.

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29. Does Warfarin have a long - medium - or short half life?
Norepinephrine
Long.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
prevention of nodal arrhythmias (SVT)

30. Name several common Macrolides (3)
Erythromycin - Azithromycin - Clarithromycin
Pentavalent Antimony
It must be Phosphorylated by Viral Thymidine Kinase
Cilastatin

31. What is the mechanism of action of Clomiphene?
edrophonium (extremely short acting anticholinesterase)
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.
Rare.
Prevents the release of Ca from SR of skeletal muscle

32. What is the MOA of Foscarnet?
Digitoxin 70% Digoxin 20-40%
Treatment of infertility.
Inhibits Viral DNA polymerase
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia

33. List the specific antidote for this toxin: TPA & Streptokinase
Aplastic anemia (dose independent) - Gray Baby Syndrome
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
- Aminocaproic acid

34. What are the four conditions in Which Omeprazole - Lansoprazole is used?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Hypersensitivity reactions
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.

35. What are four clinical uses of glucocorticoids?

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36. MOA: Block protein synthesis at 30s subunit
Aminoglycosides - Tetracyclines
- ED 50 is less than the Km (less than 50% of receptors)
- Chlorpromazine - thioridazine - haloperidol
Lipoxygenase

37. For Heparin What is the Duration of action
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.
physostigmine
Stimulates beta adrenergic receptors
Acute (hours)

38. Name two organisms Vancomycin is commonly used for?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
severe hypertension - CHF
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

39. What is the mechanism of action of Ticlopidine - Clopidogrel
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Botulinum
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Sotalol - Ibutilide - Bretylium - Amiodarone

40. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
No
Pralidoxime regenerates active cholinesterase.
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.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression

41. What are two mechanisms of action of Propythiouracil?
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
ACIDazolamide' causes acidosis
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

42. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
Fast vs. Slow Acetylators
Binding to the presynaptic alpha 2 release modulating receptors
Choline acetyltransferase
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

43. What populations are Floroquinolones contraindicated in? Why?
distal convoluted tubule (early)
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
Pregnant women - Children; because animal studies show Damage to Cartilage
Rheumatoid and osteoarthritis.

44. What is the category of drug names ending in - caine (e.g. Lidocaine)
Local anesthetic.
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
Resistant Gram - infections
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

45. Furosemide - clinical use?
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Penicillin - G
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Methylxanthine.

46. What are the major structural differences between Penicillin and Cephalosporin?
No - warfarin - unlike heparin - can cross the placenta.
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)
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

47. What are four unwanted effects of Clomiphene use?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
- Tetracycline - amiodarone - sulfonamides
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol

48. Which drug(s) cause this reaction: Gray baby syndrome?
hyperaldosteronism - K+ depletion - CHF
INH: Injures Neurons and Hepatocytes
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.
- Chloramphenicol

49. What is a Ribavirin toxicity?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Reversible block of histamine H2 receptors
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Hemolytic anemia

50. What is the mechanism of action of Heparin?
Heparin catalyzes the activation of antithrombin III.
Aminoglycosides
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).