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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. What are two types of drugs that interfere with the action of Sucralfate and why?
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
- Chlorpromazine - thioridazine - haloperidol
- Normalize K+ - Lidocaine - & Anti - dig Mab

2. What is the MOA for Clindamycin?
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Chronic anticoagulation.
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

3. Antiarrhythmic class IB- effects?
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
depresses ectopic pacemakers - especially in digoxin toxicity

4. Foscarnet toxicity?
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.
Erythromycin - Azithromycin - Clarithromycin
Nephrotoxicity
Inhibits IMP Dehydrogenase (competitively) - and therefore blocks Guanine Nucleotide synthesis

5. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Antileukotriene; blocks synthesis by lipoxygenase.
hypertension - angina - arrhythmias
Hemolytic anemia

6. 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).
Oral
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.
GI side effects. (Indomethacin is less toxic - more commonly used.)

7. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
collecting ducts
Epinephirine(Alpha1 -2 and Beta 1 -2)
toxic
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.

8. Which H2 Blocker has the most toxic effects and What are they?
- B51Naloxone / naltrexone (Narcan)
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.
Norepinephrine
GI upset

9. Ryanodine - site of action?
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Erectile dysfunction.
Diuresis in pateints with sulfa allergy
blocks SR Ca2+ channels

10. Explain potency in relation to full and partial agonists(2).
anticholinesterase glaucoma
Hypersensitivity reactions
Pyridoxine (B6) administration
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

11. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Oral treatment of superficial infections
Dopamine
Liver

12. Beta Blockers - CV toxicity?
cross - allergenic
bradycardia - AV block - CHF
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention
- Alkalinize urine & dialysis

13. Side effects of Isoniazid (INH)?
Pituitary hormone.
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Binds ergosterol - Disrupts fungal membranes
Scopolamine

14. Adverse effect of Nitroprusside?
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Ataxia - Dizziness - Slurred speech
cyanide toxicity (releases CN)
Penicillin.

15. In What population does Gray Baby Syndrome occur? Why?
Sucralfate cannot work in the presence of antacids or H2 blockers because it requires an acidic environment to polymerize.
Premature infants - because they lack UDP- glucuronyl transferase
Norepinephrine
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia

16. Which of epi - norepi - or isoproterenol results in bradycardia?
pulmonary edema - dehydration
loop diuretics - thiazides
Norepinephrine
Acute gout.

17. What is the MOA for the Tetracyclines?
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

18. What are toxic side effects for Metronidazole?
- Methylene blue
Disulfiram - like reaction with EtOH - Headache
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)

19. What is the category of drug names ending in - tidine (e.g. Cimetidine)
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
H2 antagonist
Acts as a wide spectrum carbapenem
Suramin

20. What is the mechanism of action of Heparin?
Pituitary hormone.
Delirium - Tremor - Nephrotoxicity
Heparin catalyzes the activation of antithrombin III.
- Glucocorticoid withdrawal

21. What is the major side effect for Ampicillin and Amoxicillin?
Hypersensitivity reactions
Staphlococcus aureus
The PTT.
Ipratropium

22. What is the mechanism of action of Mifepristone (RU486)?
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Beta - lactam antibiotics
Competitive inibitor of progestins at progesterone receptors.

23. Acetazolamide - clinical uses?
Albuterol - tertbutaline
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
ACE inhibitor.
PT

24. Name the steps in drug approval(4)?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
dry mouth - sedation - severe rebound hypertension
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

25. How do the Protease Inhibitors work?
Polymyxins
Neutropenia
Inhibt Assembly of new virus by Blocking Protease Enzyme
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods

26. What microorganisms are clinical indications for Tetracycline therapy?

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27. What is an additional side effect of Methicillin?
CMV - esp in Immunocompromised patients
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Interstitial nephritis

28. What is the MOA for Carbenicillin - Piperacillin - and Ticarcillin?
- Atropine & pralidoxime
Benzathine penicillin G
distal convoluted tubule (early)
Same as penicillin. Extended spectrum antibiotics

29. What are the clinical uses for Aztreonam?
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
Gram - rods: Klebsiella species - Pseudomonas species - Serratia species
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Increases coumadin metabolism

30. Hydrochlorothiazide - toxicity? (hyperGLUC - plus others)
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Yes
Chronic anticoagulation.
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

31. What physiological effects was the Anes using Atropine to tx
thiazides - amiloride
local anesthetic. CNS stimulation or depression. CV depression.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

32. Name three Antiarrhythmic drugs in class IC.
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Bleeding.
Flecainide - Encainide - Propafenone
Disulfiram - like reaction with EtOH - Headache

33. How would you treat African Trypanosomiasis (sleeping sickness)?
Suramin
Inhibit Ergosterol synthesis
Rash - Pseudomembranous colitis
troponin - tropomyosin system

34. Name two classes of drugs for HIV therapy
proximal convoluted tubule
hypertension - angina - arrhythmias
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Protease Inhibitors and Reverse Transcriptase Inhibitors

35. What drug is used during the pregnancy of an HIV+ mother? - Why?
Well tolerated in general but occasionally - Nephrotoxicity - Ototoxicity - Thrombophlebitis - diffuse flushing='Red Man Syndrome'
Penicillin - V
AZT - to reduce risk of Fetal Transmission
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

36. Can Warfarin be used during pregnancy?
No - warfarin - unlike heparin - can cross the placenta.
Inhalational general anesthetic.
Protease inhibitor.
With an amino acid change of D- ala D- ala to D- ala D- lac

37. What are three toxicities of Leuprolied?
1. Antiandrogen 2. Nausea 3. Vomiting
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
- Fluoroquinolones
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

38. What is the category of drug names ending in - azine (e.g. Chlorpromazine)
viral kinase
Modification via Acetylation - Adenylation - or Phosphorylation
Phenothiazine (neuroleptic - antiemetic).
Pentamidine

39. Why is Cilastatin administered with Imipenem?
Sulfonamides - Trimethoprim
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
torsade de pointes - excessive Beta block
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)

40. Verapamil has similar action to?
Beta Blockers
Beta - lactamase cleavage of Beta - lactam ring
Albuterol - tertbutaline
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

41. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
- Ethosuxamide - sulfonamides - lamotrigine
Norepinephrine (Alpha1 -2 and beta 1)
Penicillin.
Clavulanic acid

42. What is the mechanism of action of Misoprostol?
Polymyxins
Meningitis (H. influenza - N. meningitidis - S. pneumoniae) - Conserative treatment due to toxicities
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

43. Which drug(s) cause this reaction: Pulmonary fibrosis(3)?
new arrhythmias - hypotension
cardiac depression - peripheral edema - flushing - dizziness - constipation
- Bleomycin - amiodarone - busulfan
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride

44. Furosemide increases the excretion of What ion?
Ca2+ (Loops Lose calcium)
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Spironolactone - Triamterene - Amiloride (the K+ STAys)

45. What are the products and their toxicities of the metabolism of Methanol by / alcohol dehydrogenase?
Scopolamine
toxic
sedation - positive Coombs' test
- Formaldehyde & formic acid - severe acidosis & retinal damage

46. What anticholinesterase crosses the blood - brain - barrier?
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
physostigmine
1. Pioglitazone 2. Rosiglitazone.

47. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Paranteral (IV - SC)
- Clindamycin
- Protamine
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

48. List some specifics of lead poisoning(4)?
loop diuretics - thiazides
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Increase target cell response to insulin.

49. What is the mechanism of action of Aspirin?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
- Atropine & pralidoxime
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.

50. Which drug(s) cause this reaction: Thrombotic complications?
- Oral Contraceptives
acts at the proximal convoluted tubule to inhibit carbonic anhydrase. Causes self - limited sodium bicarb diuresis and reduction of total body bicarb stores.
Constant FRACTION eliminated per unit time.(exponential)
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.