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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 is the clinical use for Nystatin?
AZT - to reduce risk of Fetal Transmission
Topical and Oral - for Oral Candidiasis (Thrush)
sedation - positive Coombs' test
- Penicillin

2. What are three clinical uses of the NSAIDs?
troponin - tropomyosin system
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Amphotericin B - Nystatin - Fluconazole/azoles

3. How can Vancomycin - induced 'Red Man Syndrome' be prevented?
- ED 50 is less than the Km (less than 50% of receptors)
- Nitrate - hydroxocobalamin thiosulfate
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Pretreat with antihistamines and a slow infusion rate

4. What is the mecanism of action - effective period - and ineffective period of use for Cromolyn in treating Asthma?
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Rash - Pseudomembranous colitis
- Aminocaproic acid
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

5. Hydrochlorothiazide - clinical use?
Dermatophytes (tinea - ringworm)
Blocks Influenza A and RubellA; causes problems with the cerebellA
HTN - CHF - calcium stone formation - nephrogenic DI.
atropine - homatropine - tropicamide

6. How does botulinum toxin result in respiratory arrest?
Antileukotriene; blocks synthesis by lipoxygenase.
Prevents the release of ACh - Which results in muscle paralysis.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Constant FRACTION eliminated per unit time.(exponential)

7. Is toxicity rare or common whith Cromolyn used in Asthma prevention?
Rare.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs

8. What are four H2 Blockers?
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
1. Cimetadine 2. Ranitidine 3. Famotidine 4. Nizatidine
proarrhythmic
Sulfonamides - Trimethoprim

9. What is the category of drug names ending in - tropin (e.g. Somatotropin)
1. In liver - increases storage of glucose as glycogen. 2. In muscle - stimulates glycogen and protein synthesis - and K+ uptake. 3. In adipose tissue - facilitates triglyceride storage.
- Flumazenil
Pituitary hormone.
As an anticholinesterase it increases endogenous ACh and thus increases strength.

10. Why is carbachol and pilocarpine useful in treatment of glaucoma?
Hypersensitivity reactions
Intrathecally
- Vitamin K & fresh frozen plasma
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).

11. MOA: Block DNA topoisomerases
Quinolones
Penicillin.
Neomycin
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

12. MOA of Succinylcholine
Prevents the release of Ca from SR of skeletal muscle
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
cardiac depression - peripheral edema - flushing - dizziness - constipation

13. List the mechanism - clinical use - & toxicity of Paclitaxel.
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
Decreased uptake or Increased transport out of cell
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

14. Which drug(s) cause this reaction: Cinchonism (2)?
Inhibit viral DNA polymerase
- Quinidine - quinine
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Yes - it does not cross the placenta.

15. How can Isoniazid (INH)- induced neurotoxicity be prevented?
Pyridoxine (B6) administration
Intrathecally
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
depresses ectopic pacemakers - especially in digoxin toxicity

16. What are two mechanisms of action of Propythiouracil?
anticholinesterase glaucoma
BM suppression (neutropenia - anemia) - Peripheral neuropathy
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.

17. Which RT inhibitor causes Megaloblastic Anemia?
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
AZT
1. Weight gain 2. Hepatotoxicity (troglitazone)
Tricyclic antidepressant.

18. What is the effect of TCA's on the adrenergic nerve?
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Pretreat with antihistamines and a slow infusion rate
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Chronic gout.

19. Which drug(s) cause this reaction: P450 induction(6)?
bradycardia - AV block - CHF
Beta - lactam antibiotics
Doxycycline - because it is fecally eliminated
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

20. Antiarrhythmic class IB- effects?
Chronic gout.
amphetamine and ephedrine
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system

21. What additional side effects exist for Ampicillin?
Rash - Pseudomembranous colitis
Botulinum
- Tetracycline - amiodarone - sulfonamides
Megaloblastic anemia - Leukopenia - Granulocytopenia

22. For Heparin What is the Mechanism of action
Activates antithrombin III
Neurotoxicity - Acute renal tubular necrosis
Ipratropium
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

23. What enzyme does Zileuton inhibit?
Activates antithrombin III
Lipoxygenase
- aminoglycosides - loop diuretics - cisplatin
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased

24. Name two bile acid resins.
cholestyramine - colestipol
Beta - lactam antibiotics
sedation - sleep alterations
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

25. List the specific antidote for this toxin: Iron
- Deferoxamine
first dose orthostatic hypotension - dizziness - headache
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

26. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
- Flumazenil
- Bleomycin - amiodarone - busulfan
Spironolactone - Triamterene - Amiloride (the K+ STAys)

27. List the mechanism - clinical use - & toxicity of Doxorubicin.

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28. What are Aminoglycosides synergistic with?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
post MI and digitalis induced arrhythmias
Beta - lactam antibiotics
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450

29. IV Penicillin
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Penicillin - G
Peptic ulcer disease.
Inhibit viral DNA polymerase

30. Resistance mechanisms for Cephalosporins/Penicillins
Ibuprofen - Naproxen - and Indomethacin
Modification via Acetylation
Beta - lactamase cleavage of Beta - lactam ring
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

31. Which drug(s) cause this reaction: Torsade de pointes (2)?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
ACIDazolamide' causes acidosis
Bacitracin - Vancomycin
Megaloblastic anemia - Leukopenia - Granulocytopenia

32. What is the mechanism of action of Probenacid used to treat chronic gout?
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Inhibits reabsorption of uric acid.
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.
Cell membrane Ca2+ channels of cardiac sarcomere

33. List the specific antidote for this toxin: Tricyclic antidepressants
- NaHCO3
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Vitamin K & fresh frozen plasma
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)

34. What are four clinical uses of glucocorticoids?

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35. Which drug increases Sys BP w/o affecting Pulse Pressure
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Epinephrine
pulmonary edema - dehydration
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor

36. How is Griseofulvin used clinically?
Diarrhea
Oral treatment of superficial infections
Pretreat with antihistamines and a slow infusion rate
Chronic gout.

37. Antiarrhythmic class IB- clinical uses?
post MI and digitalis induced arrhythmias
AZT
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
dry mouth - sedation - severe rebound hypertension

38. Acetazolamide - toxicity?
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
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.
- aminoglycosides - loop diuretics - cisplatin
loop diuretics - spironolactone

39. Furosemide increases the excretion of What ion?
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Ca2+ (Loops Lose calcium)
- Alkalate DNA - Brain tumors - CNS toxicity
distal convoluted tubule (early)

40. What is a possible toxicity of Alpha - glucosidase inhibitors used in type -2 diabetes?
reversible SLE- like syndrome
GI disturbances.
Antileukotriene; blocks leukotriene receptors.
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

41. Antimicrobial prophylaxis for Meningococcal infection
Quinolones
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Rifampin (DOC) - minocycline

42. What anticholinesterase crosses the blood - brain - barrier?
physostigmine
Yes - it does not cross the placenta.
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic

43. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
Mg = Must go to the bathroom.
Doxycycline - because it is fecally eliminated
scopolamine
With an amino acid change of D- ala D- ala to D- ala D- lac

44. How can the t1/2 of INH be altered?
Fast vs. Slow Acetylators
AZT
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load

45. Which H2 Blocker has the most toxic effects and What are they?
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
NO AP duration effect. useful in V- tach that progresses to V- fib and in intractable SVT Last RESORT
Inhibits CMV DNA polymerase
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

46. What is a Ribavirin toxicity?
- Nitrate - hydroxocobalamin thiosulfate
Hemolytic anemia
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
It acts presynaptically to increase NE release.

47. Steady state concentration is reached in __ number of half - lifes
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
block voltage dependent L- type Ca2+ channels of cardiac and smooth muscle - decreasing contractility
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow

48. Procainamide - toxicity?
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Chronic (weeks or months)
reversible SLE- like syndrome
Penicillin - G

49. What is the effect of guanethidine on adrenergic NE release?
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
Benzodiazepine.
- Oral Contraceptives
It inhibits release of NE.

50. Name three ACE inhibitors?
Captopril - Enalapril - Lisinopril
Early myocardial infarction.
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Acetylcholinesterase; ACh is broken down into choline and acetate.