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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. MOA: Block cell wall synthesis by inhib. Peptidoglycan cross - linking (7)
Indirect agonist - uptake inhibitor
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
amphetamine and ephedrine

2. Describe the MOA of Interferons (INF)
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis
- Haloperidol - chlorpromazine - reserpine - MPTP
Cephalosporins
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)

3. What is the clinical use for Sucralfate?
1. Antiandrogen 2. Nausea 3. Vomiting
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.
Aplastic anemia (dose independent) - Gray Baby Syndrome
Peptic ulcer disease.

4. Antiarrhythmic class IV- toxicity?
Chronic (weeks or months)
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Blocks Influenza A and RubellA; causes problems with the cerebellA
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450

5. Which H2 Blocker has the most toxic effects and What are they?
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
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.
- Niacin - Ca++ channel blockers - adenosine - vancomycin
Praziquantel

6. Loop diuretics (furosemide)- site of action?
thick ascending limb
- Haloperidol - chlorpromazine - reserpine - MPTP
GI distress - Skin rash - and Seizures at high plasma levels
Ganciclovir is more toxic to host enzymes

7. What is the category of drug names ending in - oxin (e.g. Digoxin)
Gemfibrozil - Clofibrate
- ACE inhibitors (Losartan>no cough)
Cardiac glycoside (inotropic agent).
Inhibit viral DNA polymerase

8. What is the category of drug names ending in - azepam (e.g. Diazepam)
- Nitrate - hydroxocobalamin thiosulfate
depresses ectopic pacemakers - especially in digoxin toxicity
Benzodiazepine.
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

9. What drugs target anticholinesterase
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
- Hydralazine - Procainamide - INH - phenytoin
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate

10. What are the side effects of Polymyxins?
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Neurotoxicity - Acute renal tubular necrosis
thick ascending limb
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide

11. What are the Anti - TB drugs?
Modification via Acetylation - Adenylation - or Phosphorylation
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
Rifampin - Ethambutol - Streptomycin - Pyrazinamide - Isoniazid (INH)
No - warfarin - unlike heparin - can cross the placenta.

12. MOA for Penicillin (3 answers)?
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
propanolol - esmolol - metoprolol - atenolol - timolol
Inhibits Viral DNA polymerase
carbonic anhydrase inhibitors - K+ sparing diuretics

13. What is a Ribavirin toxicity?
GI disturbances.
Hemolytic anemia
Bethanechol - Neostigmine - physostigmine
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic

14. Hydrochlorothiazide - clinical use?
- Shifts the curve to the right - increases Km
Quinidine - Amiodarone - Procainamide - Disopyramide
HTN - CHF - calcium stone formation - nephrogenic DI.
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.

15. Decrease Digitoxin dose in renal failure?
VACUUM your Bed Room'
Fast vs. Slow Acetylators
NO
- Formaldehyde & formic acid - severe acidosis & retinal damage

16. Amiodarone - toxicity?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
pulmonary fibrosis - corneal deposits - hepatotoxicity - skin deposits resulting in photodermatitis - neurologic effects - consitpation - CV (bradycardia - heart block - CHF) - and hypo - or hyperthyroidism.
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone

17. What class of drug is echothiophate? What is its indication?
anticholinesterase glaucoma
aPTT (intrinsic pathway)
Because they require some residual islet function.
GI distress - Skin rash - and Seizures at high plasma levels

18. Can Warfarin be used during pregnancy?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
CMV - esp in Immunocompromised patients
No - warfarin - unlike heparin - can cross the placenta.
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

19. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Prevents the release of ACh - Which results in muscle paralysis.
Cyclooxygenases (COX I - COX II).
Amphetamine and Ephedrine
Nucleosides

20. What is the MOA of Ribavirin?
new arrhythmias - hypotension
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis
Inhalational general anesthetic.
Chronic (weeks or months)

21. What are the products and their toxicities of the metabolism of Methanol by / alcohol dehydrogenase?
- Formaldehyde & formic acid - severe acidosis & retinal damage
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
- Hydralazine - Procainamide - INH - phenytoin
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)

22. What is the category - method of use - and adverse effects of Salmeterol in Asthma treatment?
Peptic ulcer disease.
- Antipsychotics
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Penicillin.

23. What reversal agent could a Anes give to reverse the effects of Atropine
Premature infants - because they lack UDP- glucuronyl transferase
Saquinavir - Ritonavir - Indinavir - Nelfinavir
scopolamine
Bethanechol - Neostigmine - physostigmine

24. What is the category of drug names ending in - caine (e.g. Lidocaine)
- Oxalic acid - Acidosis & nephrotoxicity
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Mg = Must go to the bathroom.
Local anesthetic.

25. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Local anesthetic.
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
G6PD deficient individuals

26. Name common Polymyxins
Polymyxin B - Polymyxin E
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.
reversible SLE- like syndrome

27. Why would you use pralidoxime after exposure to an organophosphate?
dry mouth - sedation - severe rebound hypertension
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Tricyclic antidepressant.
Pralidoxime regenerates active cholinesterase.

28. IV Penicillin
Penicillin - G
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
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.
With supplemental Folic Acid

29. What is the category of drug names ending in - cillin (e.g. Methicillin)
Beta lactams - inhibit cell wall synthesis - Bactericidal
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
- Disulfram & also sulfonylureas - metronidazole
Penicillin.

30. How is Amphotericin B used clinically?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Early myocardial infarction.
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Quinidine - Amiodarone - Procainamide - Disopyramide

31. Which drug(s) cause this reaction: G6PD hemolysis(8)?
Inhibits reabsorption of uric acid.
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
Alpha -1 antagonist
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.

32. What is the mechanism of action of Sildenafil (Viagra)?
IV vitamin K and fresh frozen plasma
- Methylene blue
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.

33. Name two bile acid resins.
cholestyramine - colestipol
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Minor hepatotoxicity - Drug interactions (activates P450)
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

34. Resistance mechanisms for Aminoglycosides
Phosphorylation by a Viral Kinase
Modification via Acetylation - Adenylation - or Phosphorylation
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
toxic

35. How is Ribavirin used clinically?
Mebendazole/Thiabendazole - Pyrantel Pamoate
These B-2 agonists cause respiratory smooth muscle to relax.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
for RSV

36. How would you treat African Trypanosomiasis (sleeping sickness)?
viral kinase
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
Suramin
Penicillin.

37. What patients are at risk for life threatening hypotension When taking Sildenafil (Viagra)?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
- Clindamycin
Those patients who are taking nitrates.
Penicillin.

38. Digoxin v. Digitoxin: half life?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
- Aminocaproic acid
Digitoxin 168hrs Digoxin 40 hrs
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.

39. A group of pts are rushed into the ER complaining of excessive sweating - tearing - salivation - HA - N and V - muscle twitching - difficulty breathing and diarrhea. What drug would be the most effective immediate tx
Digitoxin 70% Digoxin 20-40%
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Activates antithrombin III

40. What is the category of drug names ending in - tidine (e.g. Cimetidine)
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.
H2 antagonist
for RSV
Long.

41. Adverse effects of beta - blockers?
Praziquantel
- Corticosteroids - heparin
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
YES

42. Adverse effects of Hydrochlorothiazide?
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.
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Directly of indirectly aid conversion of plasminogen to plasmin Which cleaves thrombin and fibrin clots. (It is claimed that tPA specifically converts fibrin - bound plasminogen to plasmin.)
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

43. K+- clinical use?
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)
depresses ectopic pacemakers - especially in digoxin toxicity
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Blood

44. What is the MOA for the Cephalosporins?
proximal convoluted tubule
- Act on same receptor - Full has greater efficacy
Beta lactams - inhibit cell wall synthesis - Bactericidal
Cephalosporins

45. What are Aminoglycosides used for clinically?
Indirect agonist - uptake inhibitor
Severe Gram - rod infections.
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Delirium - Tremor - Nephrotoxicity

46. What is the category and mechanism of action of Zafirlukast in Asthma treatment?
Antileukotriene; blocks leukotriene receptors.
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
very short acting
These B-2 agonists cause respiratory smooth muscle to relax.

47. Which of the following would atropine administration cause? Hypothermia - bradycardia - excess salivation - dry flushed skin - or diarrhea
Malaria (P. falciparum)
Slow - limited by half lives of clotting factors
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.
Benzodiazepine.

48. List the mechanism - clinical use - & toxicity of Cisplatin.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.
Binds to the Pyrophosphate Binding Site of the enzyme

49. What are the nondepolarizing neuromuscular blocking drugs?
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Those patients who are taking nitrates.

50. When is Rifampin not used in combination with other drugs?
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
-100% oxygen - hyperbaric
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
hyperkalemia - endocrine effects (gynecomastia - anti - androgen)