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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 are four unwanted effects of Clomiphene use?
- Dimercaprol - succimer
very short acting
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances

2. MOA for Penicillin (3 answers)?
For serious - Gram + multidrug - resistant organisms
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Rash - Pseudomembranous colitis
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes

3. What are signs of Sildenafil (Viagra) toxicity?
Headache - flushing - dyspepsia - blue - green color vision.
Carbenicillin - Piperacillin - and Ticarcillin
Decreased uptake or Increased transport out of cell
Polymyxin B - Polymyxin E

4. Why are albuterol and terbutaline effective in tx of acute asthmatic attacks?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
These B-2 agonists cause respiratory smooth muscle to relax.
-100% oxygen - hyperbaric
Tetracycline - Doxycycline - Demeclocycline - Minocycline

5. Which cancer drugs effect nuclear DNA (4)?
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
Penicillin.
- Quinidine - quinine
Aminoglycosides

6. What are the clinical uses for 1st Generation Cephalosporins?
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
cross - allergenic
physostigmine
Aminoglycosides - Tetracyclines

7. What is the MOA of Amantadine?
anuria - CHF
Norepinephrine (Alpha1 -2 and beta 1)
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
troponin - tropomyosin system

8. Why does atropine dilate the pupil?
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
YES
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills

9. What parasites are treated with Pyrantel Pamoate (more specific)?
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Impairs the synthesis of vitamin K- dependent clotting factors
Dopamine
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)

10. What are the clinical uses for 2nd Generation Cephalosporins?
Onchocerciasis ('river blindness'-- rIVER- mectin)
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Gram + cocci - Haemophilus influenza - Enterobacter aerogenes - Neisseria species - P. mirabilis - E. coli - K. pneumoniae - Serratia marcescens ( HEN PEcKS )
Delirium - Tremor - Nephrotoxicity

11. What are the major structural differences between Penicillin and Cephalosporin?
Blocks Norepi - but not Dopamine
proarrhythmic
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)
Inhibt Assembly of new virus by Blocking Protease Enzyme

12. What populations are Floroquinolones contraindicated in? Why?
Slow - limited by half lives of clotting factors
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Pregnant women - Children; because animal studies show Damage to Cartilage
1. Pioglitazone 2. Rosiglitazone.

13. ACE inhibitors - mechanism?
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
block Na+ channels in the cortical collecting tubule
- Vinca alkaloids(inhibit MT) - Paclitaxel

14. What is the clinical utility of clonidine?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Neutropenia
Modification via Acetylation
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

15. Why does NE result in bradycardia?
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.
Increases coumadin metabolism
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Leukotrienes increasing bronchial tone.

16. What do you treat Nematode/roundworm (pinworm - whipworm) infections with?
Mebendazole/Thiabendazole - Pyrantel Pamoate
Same as penicillin. Act as narrow spectrum antibiotics
Protease Inhibitors and Reverse Transcriptase Inhibitors
Digitoxin>95% Digoxin 75%

17. What are two indirect acting adrenergic agonists?
amphetamine and ephedrine
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
anticholinesterase glaucoma
Prevents the release of Ca from SR of skeletal muscle

18. What are Methicillin - Nafcillin - and Dicloxacillin used for clinically?
Staphlococcus aureus
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
cardiac muscle: Verapamil>Diltiazem>Nifedipine
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia

19. What is the formula for Volume of distribution (Vd)
Antileukotriene; blocks synthesis by lipoxygenase.
Vd= (Amt. of drug in body/ Plasma drug conc.)
Alpha -1 antagonist
physostigmine

20. What are the side effects of Rifampin?
Beta lactams - inhibit cell wall synthesis - Bactericidal
Minor hepatotoxicity - Drug interactions (activates P450)
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.
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

21. Explain differences between full and partial agonists(2).
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
- Act on same receptor - Full has greater efficacy
Erythromycin - Azithromycin - Clarithromycin
Gram + and Anerobes

22. What is Metronidazole combined with for 'triple therapy'? Against What organism?
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
GI disturbances.
hyperaldosteronism - K+ depletion - CHF
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

23. What are three common NSAIDS other than Aspirin?
The only local anesthetic with vasoconstrictive properties.
Ibuprofen - Naproxen - and Indomethacin
IV vitamin K and fresh frozen plasma
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

24. MOA: Block nucleotide synthesis
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Fluconazole - Ketoconazole - Clotrimazole - Miconazole - Itraconazole
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Sulfonamides - Trimethoprim

25. Side effects of Isoniazid (INH)?
Bactericidal for: Gram + rod and cocci - Gram - cocci - and Spirochetes
Modification via Acetylation - Adenylation - or Phosphorylation
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
It must be Phosphorylated by Viral Thymidine Kinase

26. List the mechanism - clinical use - & toxicity of 6 MP.
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Neutropenia
Resistant Gram - infections
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

27. How is Vancomycin used clinically?
Beta antagonist.
Scopolamine
For serious - Gram + multidrug - resistant organisms
Clavulanic acid

28. What are the clinical indications for bethanechol?
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
dizziness - flushing - constipation (verapamil) - nausea

29. Mannitol - clinical use?
ARF - shock - drug overdose - decrease intracranial/intraocular pressure
Pralidoxime regenerates active cholinesterase.
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
cardiac depression - peripheral edema - flushing - dizziness - constipation

30. Which drug(s) cause this reaction: SLE- like syndrome?
proximal convoluted tubule - thin descending limb - and collecting duct
- Hydralazine - Procainamide - INH - phenytoin
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.

31. What is the mechanism of action and clinical use of the antiandrogen Flutamide?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
- Penicillin
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

32. What is the MOA for the Macrolides?
Used in combination therapy with SMZ to sequentially block folate synthesis
Beta1 more than B2
Hypersensitivity reactions
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic

33. Name some common Sulfonamides (4)
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Nucleosides
Impairs the synthesis of vitamin K- dependent clotting factors

34. Explain pH dependent urinary drug elimination?
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.
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
AZT - to reduce risk of Fetal Transmission
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

35. What is a Ribavirin toxicity?
GI distress - Skin rash - and Seizures at high plasma levels
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut
Hemolytic anemia
GI side effects. (Indomethacin is less toxic - more commonly used.)

36. What is the category of drug names ending in - cycline (e.g. Tetracycline)
Disulfiram - like reaction with EtOH - Headache
- Lithium
Antibiotic - protein synthesis inhibitor.
BM suppression (neutropenia - anemia) - Peripheral neuropathy

37. Are not penicillinase resistant
- Shifts the curve down - reduces Vmax
Carbenicillin - Piperacillin - and Ticarcillin
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Resistant Gram - infections

38. What are Fluoroquinolones indicated for? (3)
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
Inhibits DNA dependent RNA polymerase
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms

39. When is HIV therapy initiated?
Premature infants - because they lack UDP- glucuronyl transferase
- Normalize K+ - Lidocaine - & Anti - dig Mab
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

40. Which drug increases Sys BP w/o affecting Pulse Pressure
Epinephrine
Acetylcholine esterase
Hypersensitivity reactions
- Glucocorticoid withdrawal

41. What is the possible mechanism and effect of Metformin in treating diabetes?
Protease Inhibitors and Reverse Transcriptase Inhibitors
It inhibits release of NE.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

42. As an Anes you want to use a depolarizing neuromuscular blocking drug on your pt - What do you use
CMV Retinitis in IC pts When Ganciclovir fails
Succinylcholine
Penicillin.
Reversible block of histamine H2 receptors

43. Name three Antiarrhythmic drugs in class IV.
Leukotrienes increasing bronchial tone.
Verapamil - Diltiazem - Bepridil
Mg = Must go to the bathroom.
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout

44. What are the clinical uses for 3rd Generation Cephalosporins?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

45. Ethacrynic Acid - toxicity?
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
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.

46. What are five disadvantages of Oral Contraceptives (synthetic progestins - estrogen)?
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

47. List the mechanism - clinical use - & toxicity of Nitrosureas.
Inhalational general anesthetic.
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- Alkalate DNA - Brain tumors - CNS toxicity
- Penicillamine

48. What are five toxicities associated with Tacrolimus (FK506)?
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Clindamycin

49. Isopoterenol was given to a patient with a developing AV block - why?
Stimulates beta adrenergic receptors
Gram + and Anerobes
Primaquine
Hypersensitivity reactions

50. ACE inhibitors - toxicity?
Competitive inibitor of progestins at progesterone receptors.
Penicillin - V
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Modification via Acetylation - Adenylation - or Phosphorylation