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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. Is resistant to penicillinase?
Sildenafil fills the penis
- Phenytoin
RESPIre
Imipenem

2. What beta 2 agonist will help your 21yo Astma pt?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
Albuterol - tertbutaline
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.

3. Describe the MOA of Interferons (INF)
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
cyanide toxicity (releases CN)
Yes - it does not cross the placenta.
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

4. What is the mechanism of action of Misoprostol?
Pregnant women - Children; because animal studies show Damage to Cartilage
TMP- SMZ (DOC) - aerosolized pentamidine
cardiac muscle: Verapamil>Diltiazem>Nifedipine
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

5. What is the mechanism of action of Ticlopidine - Clopidogrel
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Lidocaine - Mexiletine - Tocainide
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
Epinephirine(Alpha1 -2 and Beta 1 -2)

6. Adverse effects of Nifedipine - verapamil?
dizziness - flushing - constipation (verapamil) - nausea
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Inhibits cell wall mucopeptide formation - Bactericidal
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).

7. Side effects of Isoniazid (INH)?
Bleeding.
HTN - CHF - calcium stone formation - nephrogenic DI.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

8. What is the MOA of the RT Inhibitors?
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

9. What are the phases of succinylcholine neuromuscular blockade?
Amphetamine and Ephedrine
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.
K+ wasting - metabolic alkalosis - hypotension - ototoxicity
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

10. Adverse effects of Losartan?
- Daunorubicin & Doxorubicin
fetal renal toxicity - hyperkalemia
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

11. What are common toxicities associated with Macrolides? (4)
Give an antichloinesterase - neostigmine - edrophonium - etc
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

12. Which drug(s) cause this reaction: Fanconi's syndrome?
GnRH analog with agonist properties When used in pulsatile fashion and antagonist properties When used in continuous fashion - causing a transient initial burst of LH and FSH
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
- Tetracycline
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

13. What are three possible complications of Heparin therapy?
Gram + - Gram - - Norcardia - Chlamydia
1. Bleeding 2. Thrombocytopenia 3. Drug - drug interactions
Digitoxin 70% Digoxin 20-40%
Beta - lactamase cleavage of Beta - lactam ring

14. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
GI side effects. (Indomethacin is less toxic - more commonly used.)
GnRH analog with agonist properties When used in pulsatile fashion and antagonist properties When used in continuous fashion - causing a transient initial burst of LH and FSH
Beta - lactam antibiotics
Rare.

15. Name common Polymyxins
Rifampin (DOC) - minocycline
Polymyxin B - Polymyxin E
collecting ducts
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

16. List the specific antidote for this toxin: Cyanide
compensatory tachycardia - fluid retention - lupus - like syndrome
- Nitrate - hydroxocobalamin thiosulfate
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts

17. What is the MOA of Ganciclovir?
Inhibits CMV DNA polymerase
Captopril - Enalapril - Lisinopril
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species

18. In coma situations you rule out What (7)?

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19. Name the common Non - Nucleoside Reverse Transcriptase Inhibitors
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
Inhibition of 50S peptidyl transferase - Bacteriostatic
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Nevirapine - Delavirdine

20. What are two Glitazones?
penicillinase resistant
Chronic gout.
- Atropine & pralidoxime
1. Pioglitazone 2. Rosiglitazone.

21. What drug is used during the pregnancy of an HIV+ mother? - Why?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Beta lactams - inhibit cell wall synthesis - Bactericidal
AZT - to reduce risk of Fetal Transmission
- Cloazapine - carbamazapine - colchicine - PTU

22. What is the clinical use for Sucralfate?
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
Peptic ulcer disease.
Decreased uptake or Increased transport out of cell
Large anionic polymer - acidic

23. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.
- Disulfram & also sulfonylureas - metronidazole
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

24. Bretyllium - toxicity?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
new arrhythmias - hypotension
Sulfonamides - Trimethoprim
Ipratropium

25. Which cancer drugs work at the level of mRNA(2)?
- Steroids - Tamoxifen
compensatory tachycardia - fluid retention - lupus - like syndrome
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD
Beta lactams - inhibit cell wall synthesis - Bactericidal

26. Which diuretics cause acidosis?
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Minor hepatotoxicity - Drug interactions (activates P450)
carbonic anhydrase inhibitors - K+ sparing diuretics
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

27. What is a prerequisite for Acyclovir activation?
CMV - esp in Immunocompromised patients
It must be Phosphorylated by Viral Thymidine Kinase
Penicillin.
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)

28. Name three Antiarrhythmic drugs in class IB.
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
Staphlococcus aureus
Long.
Lidocaine - Mexiletine - Tocainide

29. Adenosine - clinical use?
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Resistant Gram - infections
DOC in diagnosing and abolishing AV nodal arrhythmias
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

30. Antiarrhythmic class IV- toxicity?
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Pralidoxime regenerates active cholinesterase.
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

31. List the specific antidote for this toxin: Digitalis
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
- Normalize K+ - Lidocaine - & Anti - dig Mab
- Isoniazid
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome

32. How would you treat African Trypanosomiasis (sleeping sickness)?
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Suramin
competitive inhibirot of aldosterone in the cortical collecting tubule
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).

33. What neurotransmitter does Amantadine affect? How does it influence this NT?
Dopamine; causes its release from intact nerve terminals
Prevents the release of Ca from SR of skeletal muscle
No
Ganciclovir is more toxic to host enzymes

34. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
Digitoxin 168hrs Digoxin 40 hrs
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
These B-2 agonists cause respiratory smooth muscle to relax.
Hydralazine and Minoxidil

35. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.

36. Mannitol - site of action?
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
proximal convoluted tubule - thin descending limb - and collecting duct
Nucleosides
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.

37. What is the clinical utility of clonidine?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Bleeding.
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).

38. Which drug(s) cause this reaction: Adrenocortical Insufficiency
- Glucocorticoid withdrawal
Prevents the release of ACh - Which results in muscle paralysis.
scopolamine
Digoxin=urinary Digitoxin=biliary

39. List the specific antidote for this toxin: Benzodiazepines
Ataxia - Dizziness - Slurred speech
Reversible block of histamine H2 receptors
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.
- Flumazenil

40. How can Isoniazid (INH)- induced neurotoxicity be prevented?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Phosphorylation by a Viral Kinase
Pyridoxine (B6) administration
orthostatic and exercise hypotension - sexual dysfunction - diarrhea

41. What is the formula for Volume of distribution (Vd)
Same as penicillin. Extended spectrum antibiotics
Bleeding.
Vd= (Amt. of drug in body/ Plasma drug conc.)
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

42. Antiarrhythmic class II- effects?
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
carbonic anhydrase inhibitors - K+ sparing diuretics
- Fluoroquinolones
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise

43. Do Tetracyclines penetrate the CNS?
Only in limited amounts
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
Modification via Acetylation - Adenylation - or Phosphorylation
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy

44. What are the major structural differences between Penicillin and Cephalosporin?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
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)
Enterobacter
- Normalize K+ - Lidocaine - & Anti - dig Mab

45. What is an additional side effect of Methicillin?
Only in limited amounts
Interstitial nephritis
Decreases synthesis of Mycolic Acid
Blocks Norepi - but not Dopamine

46. What are five possible toxic effects of Aspirin therapy?

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47. Beta Blockers - CNS toxicity?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
sedation - sleep alterations
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
- Phenytoin

48. What enzyme does Zileuton inhibit?
Aminoglycosides
Lipoxygenase
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.
Stimulates beta adrenergic receptors

49. Resistance mechanisms for Sulfonamides
Mebendazole/Thiabendazole - Pyrantel Pamoate
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Decreased uptake or Increased transport out of cell

50. Verapamil has similar action to?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Inhalational general anesthetic.
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.
Beta Blockers