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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. Are not penicillinase resistant
Gram + - Gram - - Norcardia - Chlamydia
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Carbenicillin - Piperacillin - and Ticarcillin

2. Are penicillinase resistant
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
Resistant Gram - infections
Methicillin - Nafcillin - and Dicloxacillin
Inhibits CMV DNA polymerase

3. Name three Antiarrhythmic drugs in class IV.
Activates antithrombin III
Verapamil - Diltiazem - Bepridil
physostigmine
very short acting

4. Toxic side effects of the Azoles?
Inhibit viral DNA polymerase
- Antipsychotics
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Interferes with microtubule function - disrupts mitosis - inhibits growth

5. Describe Phase II metabolism in liver(3)?
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
- Formaldehyde & formic acid - severe acidosis & retinal damage
With an amino acid change of D- ala D- ala to D- ala D- lac

6. What are two indirect acting adrenergic agonists?
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Captopril - Enalapril - Lisinopril
amphetamine and ephedrine

7. Ganciclovir associated toxicities?
bradycardia - AV block - CHF
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)

8. Hydrochlorothiazide - clinical use?
Onchocerciasis ('river blindness'-- rIVER- mectin)
HTN - CHF - calcium stone formation - nephrogenic DI.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Saquinavir - Ritonavir - Indinavir - Nelfinavir

9. What is the MOA of Ganciclovir?
Inhibits CMV DNA polymerase
- Ethanol - dialysis - & fomepizole
- Ethosuxamide - sulfonamides - lamotrigine
Bleeding.

10. Which RT inhibitor causes Megaloblastic Anemia?
- B51Naloxone / naltrexone (Narcan)
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
AZT
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

11. What is the clinical use for Sildenafil (Viagra)?
The PT.
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Erectile dysfunction.
for RSV

12. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Antifungal.
anticholinesterase glaucoma
- Ethosuxamide - sulfonamides - lamotrigine

13. Name the steps in drug approval(4)?
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
AZT - to reduce risk of Fetal Transmission
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)

14. Specifically - How does Foscarnet inhibit viral DNA pol?
Binds to the Pyrophosphate Binding Site of the enzyme
very short acting
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Norepinephrine

15. What are the major structural differences between Penicillin and Cephalosporin?
Mg = Must go to the bathroom.
Digitoxin 70% Digoxin 20-40%
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
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)

16. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Same as penicillin. Extended spectrum antibiotics

17. What is the mechanism of action of Probenacid used to treat chronic gout?
Inhibits reabsorption of uric acid.
Dopamine; causes its release from intact nerve terminals
Bleeding.
Neutropenia

18. For Warfarin What is the Route of administration
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Interstitial nephritis
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Oral

19. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Choline acetyltransferase
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
It must be Phosphorylated by Viral Thymidine Kinase

20. Sotalol - toxicity?
dizziness - flushing - constipation (verapamil) - nausea
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.
torsade de pointes - excessive Beta block
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)

21. Ryanodine - site of action?
blocks SR Ca2+ channels
- Glucocorticoid withdrawal
Inhibition of 50S peptidyl transferase - Bacteriostatic
sedation - positive Coombs' test

22. List five common glucocorticoids.
Digitoxin 70% Digoxin 20-40%
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Potent immunosuppressive used in organ transplant recipients.

23. Name three Antiarrhythmic drugs in class IB.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Lidocaine - Mexiletine - Tocainide
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.
- aminoglycosides - loop diuretics - cisplatin

24. Antiarrhythmic Class III- effects?
AluMINIMUM amount of feces.
compensatory tachycardia - fluid retention - lupus - like syndrome
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail

25. Quinidine - toxicity?
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
cross - allergenic

26. What is the memory key for organisms treated with Tetracyclines?

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27. Which drug(s) cause this reaction: Torsade de pointes (2)?
Protease Inhibitors and Reverse Transcriptase Inhibitors
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

28. Aztreonam is not usually...
Hypersensitivity reactions
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
toxic
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

29. Name the common Fluoroquinolones (6)
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Imipenem
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Acetylcholine esterase

30. Which drug(s) cause this reaction: Osteoporosis (2)?
- Corticosteroids - heparin
Competitive inibitor of progestins at progesterone receptors.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

31. What is the mechanism of action of Misoprostol?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
thick ascending limb
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
TMP- SMZ

32. What are two types of drugs that interfere with the action of Sucralfate and why?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
TCA

33. MOA: Block peptidoglycan synthesis
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
ACE inhibitor.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Bacitracin - Vancomycin

34. Name some common Sulfonamides (4)
These B-2 agonists cause respiratory smooth muscle to relax.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Pseudomonas species and Gram - rods
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)

35. Common side effects associated with Clindamycin include?
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Hypersensitivity reactions
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis

36. Which drug(s) cause this reaction: Tendonitis and rupture?
- Disulfram & also sulfonylureas - metronidazole
These B-2 agonists cause respiratory smooth muscle to relax.
- Fluoroquinolones
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.)

37. Procainamide - toxicity?
distal convoluted tubule (early)
- NaHCO3
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
reversible SLE- like syndrome

38. Spironolactone - mechanism?
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
competitive inhibirot of aldosterone in the cortical collecting tubule
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
Antileukotriene; blocks synthesis by lipoxygenase.

39. Decrease Digitoxin dose in renal failure?
Diarrhea
NO
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
Penicillin - G

40. Which drug(s) cause this reaction: Hot flashes?
Bethanechol - Neostigmine - physostigmine
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
- Tamoxifen

41. What is the MOA of Isoniazid (INH)?
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Bleeding.
Decreases synthesis of Mycolic Acid
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori

42. What are the clinical indications for bethanechol?
Beta - lactam antibiotics
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.
- Antipsychotics

43. Name some common Tetracyclines (4)
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
DOC in diagnosing and abolishing AV nodal arrhythmias
Tetracycline - Doxycycline - Demeclocycline - Minocycline

44. IV Penicillin
Penicillin - G
Antileukotriene; blocks synthesis by lipoxygenase.
Captopril - Enalapril - Lisinopril
anticholinesterase glaucoma

45. Ibutilide - toxicity?
cross - allergenic
- Alkalinize urine & dialysis
Bethanechol - Neostigmine - physostigmine
torsade de pointes

46. Name several common Macrolides (3)
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
HTN - CHF - calcium stone formation - nephrogenic DI.
Erythromycin - Azithromycin - Clarithromycin
cholestyramine - colestipol

47. How does a noncompetitive antagonist effect an agonist?
INH: Injures Neurons and Hepatocytes
- Shifts the curve down - reduces Vmax
The PT.
- Tetracycline - amiodarone - sulfonamides

48. Acetazolamide - mechanism?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Indirect agonist - uptake inhibitor
Beta adrenergic receptors and Ca2+ channels (stimulatory)

49. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Epinephirine(Alpha1 -2 and Beta 1 -2)
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

50. What is the MOA of Ribavirin?
Delirium - Tremor - Nephrotoxicity
AZT
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Abortifacient.