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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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1. Name three Antiarrhythmic drugs in class IC.
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Choline acetyltransferase
Flecainide - Encainide - Propafenone
Aminoglycosides

2. How can the toxic effects of TMP be ameliorated?
- Methylene blue
TCA
With supplemental Folic Acid
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.

3. What is the category of drug names ending in - azol (e.g. Ketoconazole)
Cephalosporins
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
dizziness - flushing - constipation (verapamil) - nausea
Antifungal.

4. Why is Cilastatin administered with Imipenem?
toxic
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Abortifacient.

5. Acetazolamide causes?

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6. MOA: Block mRNA synthesis
for RSV
Rifampin
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.

7. What are are the Sulfonylureas (general description) and What is their use?
Can affect absorption - bioavailability - or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying.
1. Antiandrogen 2. Nausea 3. Vomiting
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
pulmonary edema - dehydration

8. Describe Phase I metabolism in liver(3)?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
Competitive inibitor of progestins at progesterone receptors.
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes

9. What is the mechanism of action of Omeprazole - Lansoprazole?
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Protease Inhibitors and Reverse Transcriptase Inhibitors
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

10. ___________ are Teratogenic
Chronic gout.
atropine - homatropine - tropicamide
Blood
Aminoglycosides

11. What is the loading dose formula?
Inhibt Assembly of new virus by Blocking Protease Enzyme
- Shifts the curve to the right - increases Km
Suramin
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.

12. Antiarrhythmic class IV- effects?
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
decrease conduction velocity - increase ERP - increase PR interval
The PTT.

13. What is combination TMP- SMZ used to treat?
severe hypertension - CHF
CMV Retinitis in IC pts When Ganciclovir fails
Prevents the release of Ca from SR of skeletal muscle
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia

14. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
- Corticosteroids - heparin
Only in limited amounts
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

15. How would hemicholinium treatment affect cholinergic neurons?
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Minor hepatotoxicity - Drug interactions (activates P450)
Bethanechol - Neostigmine - physostigmine
- Daunorubicin & Doxorubicin

16. What side effect of using atropine to induce pupillary dilation would you expect?
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Chronic gout.
Nucleosides
Hypersensitivity reactions

17. How would you reverse the effect of a neuromuscular blocking agent?
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.
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
It acts presynaptically to increase NE release.
Give an antichloinesterase - neostigmine - edrophonium - etc

18. For Heparin What is the Route of administration
Large anionic polymer - acidic
Small lipid - soluble molecule
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Paranteral (IV - SC)

19. How does NE modulate its own release? What other neurotransmitter has this same effect?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
penicillinase resistant
cortical collecting tubule
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels

20. What is a possible toxicity of Ticlopidine - Clopidogrel usage?
The PT.
Neutropenia (ticlopidine); reserved for those who cannot tolerate aspirin.
atropine - homatropine - tropicamide
Chronic anticoagulation.

21. What is a common side effect of Colchicine used to treat acute gout - especially When given orally?
Suramin
GI side effects. (Indomethacin is less toxic - more commonly used.)
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Constant FRACTION eliminated per unit time.(exponential)

22. What are two clinical uses of Azathioprine?
1. Kidney transplantation 2. Autoimmune disorders (including glomerulonephritis and hemolytic anemia)
Liver
1. Acarbose 2. Miglitol
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.

23. What is the MOA for Amphotericin B?
Diuresis in pateints with sulfa allergy
Binds Ergosterol - forms Membrane Pores that Disrupt Homeostatis
Digoxin=urinary Digitoxin=biliary
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

24. What are Aminoglycosides used for clinically?
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
Severe Gram - rod infections.
Alpha -1 antagonist
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor

25. Digoxin v. Digitoxin: protein binding?
Benzodiazepine.
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium
Digitoxin 70% Digoxin 20-40%
Blood

26. How do we stop angina?
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
TMP- SMZ (DOC) - aerosolized pentamidine
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

27. What is the lab value used to monitor the effectiveness of Warfarin therapy?
The PT.
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Antiprotozoal: Giardia - Entamoeba - Trichomonas - Gardnerella vaginalis Anaerobes: Bacteroides - Clostridium

28. Which RT inhibitor causes Megaloblastic Anemia?
Benzathine penicillin G
AZT
Gemfibrozil - Clofibrate
RESPIre

29. For Warfarin What is the Treatment for overdose
Ca2+ (Loops Lose calcium)
Paranteral (IV - SC)
IV vitamin K and fresh frozen plasma
fetal renal toxicity - hyperkalemia

30. Esmolol - short or long acting?
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
- Daunorubicin & Doxorubicin
very short acting
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.

31. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Tricyclic antidepressant.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

32. What are the clinical uses for Ticlopidine - Clopidogrel?
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Rapid (seconds)
Succinylcholine

33. Spironolactone - mechanism?
- Physostigmine salicylate
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
competitive inhibirot of aldosterone in the cortical collecting tubule

34. How are Sulfonamides employed clinically?
- N- acetylcystine
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Gram + - Gram - - Norcardia - Chlamydia
K+ wasting - metabolic alkalosis - hypotension - ototoxicity

35. What are Polymyxins used for?
Hemolytic anemia
Resistant Gram - infections
Penicillin.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

36. What is a Ribavirin toxicity?
Hemolytic anemia
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Short.

37. How is Amphotericin B used clinically?
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Systemic mycoses
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Rash - Pseudomembranous colitis

38. ________ ae not resistant to penicillinase - - but they are less susceptible than the other Beta lactams
Cephalosporins
- EDTA - dimercaprol - succimer - & penicillamine
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Mebendazole/Thiabendazole - Pyrantel Pamoate

39. What conditions would you use dantrolene?
Beta adrenergic receptors and Ca2+ channels (stimulatory)
It affects beta receptors equally and is used in AV heart block (rare).
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.

40. List the specific antidote for this toxin: Amphetamine
- Ammonium Chloride
1. Reliable (<1% failure) 2. Lowers risk of endometrial and ovarian cancer 3. Decreased incidence of ectopic pregnancy 4. Lower risk of pelvic infections 5. Regulation of menses
blocks SR Ca2+ channels
Aminoglycosides

41. What are two toxicities of the Glitazones?
INH: Injures Neurons and Hepatocytes
1. Weight gain 2. Hepatotoxicity (troglitazone)
Norepinephrine
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.

42. MOA: Disrupt fungal cell membranes
- Lithium
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Amphotericin B - Nystatin - Fluconazole/azoles

43. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
Edrophonium
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Saquinavir - Ritonavir - Indinavir - Nelfinavir
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids

44. What is the mecanism of action of Sucralfate?
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
DOC in diagnosing and abolishing AV nodal arrhythmias
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
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.

45. What is the clinical use of Tacrolimus (FK506)?
hypertension - angina - arrhythmias
- Deferoxamine
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Potent immunosuppressive used in organ transplant recipients.

46. What drugs target anticholinesterase
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
1. Pioglitazone 2. Rosiglitazone.
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Beta lactams - inhibit cell wall synthesis - Bactericidal

47. How is Trimethoprim used clinically?
- B51Naloxone / naltrexone (Narcan)
scopolamine
Used in combination therapy with SMZ to sequentially block folate synthesis
- Chloramphenicol

48. For Warfarin What is the Duration of action
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Chronic (weeks or months)

49. If a patient is given hexamethonium - What would happen to his/her heart rate?
Cyclooxygenases (COX I - COX II).
- Cloazapine - carbamazapine - colchicine - PTU
The PT.
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.

50. Nifedipine has similar action to?
Nitrates
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.
reversible SLE- like syndrome
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas