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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. List the specific antidote for this toxin: Heparin
- Protamine
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
Inhibits reabsorption of uric acid.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA

2. What is the MOA for the Cephalosporins?
Digitoxin 168hrs Digoxin 40 hrs
Beta lactams - inhibit cell wall synthesis - Bactericidal
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Carbachol - pilocarpine - physostigmine - echothiophate

3. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Flecainide - Encainide - Propafenone
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Does not cross
Cyclooxygenases (COX I - COX II).

4. Common toxicities associated with Fluoroquinolones?
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Alpha -1 antagonist
GI upset - Superinfections - Skin rashes - Headache - Dizziness
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail

5. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
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.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Beta lactams - inhibit cell wall synthesis - Bactericidal
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

6. Furosemide - clinical use?
Phosphorylation by a Viral Kinase
sedation - positive Coombs' test
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Interferes with microtubule function - disrupts mitosis - inhibits growth

7. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Mg = Must go to the bathroom.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Those patients who are taking nitrates.

8. Name two LPL stimulators.
Gemfibrozil - Clofibrate
Pretreat with antihistamines and a slow infusion rate
Cell membrane Ca2+ channels of cardiac sarcomere
Edrophonium

9. Spironolactone - mechanism?
competitive inhibirot of aldosterone in the cortical collecting tubule
Nifedipine - Verapamil - Diltiazem
penicillinase resistant
Tricyclic antidepressant.

10. Adverse effects of Hydralazine?
penicillinase resistant
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

11. Cautions When using Amiodarone?
Due to the presence of a bulkier R group
physostigmine
check PFTs - LFTs - and TFTs
Chronic gout.

12. How is Chloramphenical used clinically?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Pentavalent Antimony
- N- acetylcystine

13. What is the MOA for the Tetracyclines?
Yes - it does not cross the placenta.
Non - Nucleosides
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic

14. What effect would atropine have on the preganglionic sympathetic activation of sweat glands? Would this person sweat?
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Beta lactams - inhibit cell wall synthesis - Bactericidal

15. Mnemonic for Foscarnet?
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Cyclooxygenases (COX I - COX II).
Bleeding.
Foscarnet = pyroFosphate analog

16. What are three clinical uses of the NSAIDs?
Local anesthetic.
Beta - lactam antibiotics
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

17. What is the mechanism of action of Clomiphene?
These B-2 agonists cause respiratory smooth muscle to relax.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Onchocerciasis ('river blindness'-- rIVER- mectin)
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.

18. Hydralazine - clinical use?
severe hypertension - CHF
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
Diuresis in pateints with sulfa allergy
hyperaldosteronism - K+ depletion - CHF

19. What are two types of drugs that interfere with the action of Sucralfate and why?
- B51Naloxone / naltrexone (Narcan)
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Tendonitis and Tendon rupture

20. Mannitol - contraindications?
Digitoxin 70% Digoxin 20-40%
anuria - CHF
Chronic Hepatitis A and B - Kaposi's Sarcoma
Pseudomembranous colitis (C. difficile) - fever - diarrhea

21. Name the common Non - Nucleoside Reverse Transcriptase Inhibitors
Nevirapine - Delavirdine
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Megaloblastic anemia - Leukopenia - Granulocytopenia
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

22. 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).
Epinephrine
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
- acetylation - glucuron. - & sulfation - Conjugation - Polar product

23. MOA of Succinylcholine
anticholinesterase glaucoma
Acute (hours)
Succinylcholine
Prevents the release of Ca from SR of skeletal muscle

24. Ryanodine - site of action?
decrease
Rapid (seconds)
blocks SR Ca2+ channels
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma

25. Why does atropine dilate the pupil?
1. Hypoglycemia (more common with 2nd - generation drugs: glyburide - glipizide) 2. Disulfiram - like effects (not seen with 2nd - generation drugs).
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
sedation - positive Coombs' test

26. Common side effects associated with Clindamycin include?
for RSV
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

27. What are the clinical uses for 2nd Generation Cephalosporins?
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Hypersensitivity reactions

28. MOA: Disrupt fungal cell membranes
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
Amphotericin B - Nystatin - Fluconazole/azoles
cardiac depression - peripheral edema - flushing - dizziness - constipation
- Ethanol - dialysis - & fomepizole

29. What is the clinical use for Nystatin?
Topical and Oral - for Oral Candidiasis (Thrush)
Systemic mycoses
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

30. What populations are Floroquinolones contraindicated in? Why?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Pregnant women - Children; because animal studies show Damage to Cartilage
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

31. What is the mechanism of action of Colchicine used to treat acute gout?
Megaloblastic anemia - Leukopenia - Granulocytopenia
- Ethanol - dialysis - & fomepizole
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Rifampin (DOC) - minocycline

32. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
sedation - depression - nasal stuffiness - diarrhea

33. How are the HIV drugs used clinically?

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34. List the specific antidote for this toxin: Benzodiazepines
- Flumazenil
Inhibition of 50S peptidyl transferase - Bacteriostatic
- Alkalinize urine & dialysis
Vd= (Amt. of drug in body/ Plasma drug conc.)

35. Describe Phase I metabolism in liver(3)?
Early myocardial infarction.
Tetracycline - Doxycycline - Demeclocycline - Minocycline
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity

36. What is the category of drug names ending in - cillin (e.g. Methicillin)
Dry flushed skin - due to inhibition of sympathetic post - ganglionic blockade on muscarinic receptors of sweat glands. All others are opposite of What would be expected.
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Penicillin.
TMP- SMZ

37. What is the category of drug names ending in - terol (e.g. Albuterol)
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Beta -2 agonist.

38. Adverse effects of Methyldopa?

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39. List the specific antidote for this toxin: Anticholinesterases (organophosphate.)
Ipratropium
- Atropine & pralidoxime
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain

40. Explain pH dependent urinary drug elimination?
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Erythromycin - Azithromycin - Clarithromycin

41. How can the t1/2 of INH be altered?
- Bleomycin - amiodarone - busulfan
Diarrhea
Fast vs. Slow Acetylators
Binding to the presynaptic alpha 2 release modulating receptors

42. What is the category of drug names ending in - caine (e.g. Lidocaine)
Local anesthetic.
severe hypertension - CHF
Erythromycin - Azithromycin - Clarithromycin
Antibiotic - protein synthesis inhibitor.

43. What is the MOA for Acyclovir?
1. Acarbose 2. Miglitol
Inhibit viral DNA polymerase
Protamine sulfate
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)

44. How do spare receptors effect the Km?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Edrophonium
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
- ED 50 is less than the Km (less than 50% of receptors)

45. What are the side effects of Rifampin?
Chronic (weeks or months)
Minor hepatotoxicity - Drug interactions (activates P450)
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Increase target cell response to insulin.

46. Clinical use of Isoniazid (INH)?
Acetylcholine esterase
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
For serious - Gram + multidrug - resistant organisms
hyperaldosteronism - K+ depletion - CHF

47. What are four unwanted effects of Clomiphene use?
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Mebendazole/Thiabendazole - Pyrantel Pamoate
sedation - positive Coombs' test

48. Which drug(s) cause this reaction: Aplastic anemia (5)?
Inhibits CMV DNA polymerase
Intrathecally
Hydralazine and Minoxidil
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin

49. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
YES
- Ethosuxamide - sulfonamides - lamotrigine
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin
reversible SLE- like syndrome

50. What is the category of drug names ending in - cycline (e.g. Tetracycline)
- Vitamin K & fresh frozen plasma
carbonic anhydrase inhibitors - K+ sparing diuretics
Antibiotic - protein synthesis inhibitor.
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.