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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. List the mechanism - clinical use - & toxicity of Etoposide.
Chronic (weeks or months)
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Binds to the Pyrophosphate Binding Site of the enzyme

2. What is Imipenem always administered with?
These B-2 agonists cause respiratory smooth muscle to relax.
Cyclooxygenases (COX I - COX II).
Cilastatin
- NaHCO3

3. What two vasodilators require simultaneous treatment with beta blockers to prevent reflex tachycardia and diuretics to prevent salt retention?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
Hydralazine and Minoxidil
AmOxicillin has greater Oral bioavailability
Polymyxins

4. What is the clinical use of Tacrolimus (FK506)?
Potent immunosuppressive used in organ transplant recipients.
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
Onchocerciasis ('river blindness'-- rIVER- mectin)
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome

5. Name three Antiarrhythmic drugs in class IC.
- aminoglycosides - loop diuretics - cisplatin
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
Flecainide - Encainide - Propafenone

6. Hydrochlorothiazide - clinical use?
Used in combination therapy with SMZ to sequentially block folate synthesis
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
- Normalize K+ - Lidocaine - & Anti - dig Mab
HTN - CHF - calcium stone formation - nephrogenic DI.

7. What is the category - desired effect - and possible mechanism of Theophylline in treating Asthma?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Blocks Influenza A and RubellA; causes problems with the cerebellA
TCA
DOC in diagnosing and abolishing AV nodal arrhythmias

8. Adverse effects of Prazosin?
loop diuretics - thiazides
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
first dose orthostatic hypotension - dizziness - headache
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.

9. What is the category of drug names ending in - zosin (e.g. Prazosin)
Alpha -1 antagonist
Abortifacient.
NO
1. Antiandrogen 2. Nausea 3. Vomiting

10. What is the MOA for Vancomycin?
effective in torsade de pointes and digoxin toxicity
Inhibits cell wall mucopeptide formation - Bactericidal
Polymyxin B - Polymyxin E
Carbenicillin - Piperacillin - and Ticarcillin

11. What are three unwanted effects of Mifepristone?
Forms toxic metabolites in the bacterial cell - Bactericidal
- Penicillamine
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Minor hepatotoxicity - Drug interactions (activates P450)

12. These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
Inhalational general anesthetic.
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Amphetamine and Ephedrine
Phase 1 = prolonged depolarization - no antidote - effect potentiated by anticholinesterase; Phase 2 = repolarized but blocked - an anticholinesterase is the antidote for this phase.

13. What are two conditions in Which COX-2 inhibitors might be used?
G6PD deficient individuals
Binds to the Pyrophosphate Binding Site of the enzyme
Rheumatoid and osteoarthritis.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression

14. What is the MOA for Rifampin?
No - hemicholinum block the uptake of Choline and thus Ach synthesis
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
Inhibits DNA dependent RNA polymerase
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

15. For Warfarin What is the Duration of action
Treatment of infertility.
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Chronic (weeks or months)

16. What are common toxicities associated with Macrolides? (4)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
- Methotrexate - 5 FU - 6 mercaptopurine
Severe Gram - rod infections.
- Daunorubicin & Doxorubicin

17. What type of neurological blockade would hexamethonium create?
H2 antagonist
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

18. What is the MOA for Nystatin?
Onchocerciasis ('river blindness'-- rIVER- mectin)
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Butyrophenone (neuroleptic).
Binds ergosterol - Disrupts fungal membranes

19. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
IV vitamin K and fresh frozen plasma
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Pregnant women - Children; because animal studies show Damage to Cartilage

20. Name four Antiarrhythmic drugs in class IA.
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Stimulates beta adrenergic receptors
Quinidine - Amiodarone - Procainamide - Disopyramide

21. What is the MOA for the Aminoglycosides?
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
-100% oxygen - hyperbaric
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

22. What is the mechanism of action of NSAIDs other than Aspirin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
effective in torsade de pointes and digoxin toxicity
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

23. What cholinomimetics might your pt be taking for his glaucoma
loop diuretics - thiazides
Pentavalent Antimony
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Carbachol - pilocarpine - physostigmine - echothiophate

24. Name the common Non - Nucleoside Reverse Transcriptase Inhibitors
Inhalational general anesthetic.
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
Nevirapine - Delavirdine
NE increases bp - Which stimulates baroreceptors in the carotid sinus and the aorta. The CNS signals through vagal stimulation to decrease heart rate.

25. What are common side effects of Amphotericin B?
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Praziquantel
decrease myocardial O2 consumption by: 1- decreasing end diastolic volume 2- decreasing BP 3- decreasing HR 4- decreasing contractility 5- decreasing ejection time
sedation - positive Coombs' test

26. What populations are Floroquinolones contraindicated in? Why?
edrophonium (extremely short acting anticholinesterase)
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Pregnant women - Children; because animal studies show Damage to Cartilage
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

27. What is an additional side effect of Methicillin?
- Dimercaprol - succimer
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Ataxia - Dizziness - Slurred speech
Interstitial nephritis

28. What is the category of drug names ending in - barbital (e.g. Phenobarbital)
1. Buffalo hump 2. Moon facies 3. Truncal obesity 4. Muscle wasting 5. Thin skin 6. Easy bruisability 7. Osteoporosis 8. Adrenocortical atrophy 9. Peptic ulcers
- Oral Contraceptives
proximal convoluted tubule - thin descending limb - and collecting duct
Babiturate.

29. Beta Blockers - CV toxicity?
No - warfarin - unlike heparin - can cross the placenta.
propanolol - esmolol - metoprolol - atenolol - timolol
bradycardia - AV block - CHF
- Halothane - Valproic acid - acetaminophen - Amantia phalloides

30. What is a mnemonic to remember Amantadine's function?
- Deferoxamine
alpha -1 > alpha -2; used as a pupil dilator - vasoconstrictor - and for nasal decongestion
- Methotrexate - 5 FU - 6 mercaptopurine
Blocks Influenza A and RubellA; causes problems with the cerebellA

31. What are two mechanisms of action of Propythiouracil?
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
Leukotrienes increasing bronchial tone.
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Increases coumadin metabolism

32. Describe first - order kinetics?
Constant FRACTION eliminated per unit time.(exponential)
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
ACIDazolamide' causes acidosis
1. Pioglitazone 2. Rosiglitazone.

33. What enzyme is responsible for the degredation of Ach
Acetylcholine esterase
very short acting
Ataxia - Dizziness - Slurred speech
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes

34. What is the category of drug names ending in - caine (e.g. Lidocaine)
- Flumazenil
Modification via Acetylation - Adenylation - or Phosphorylation
ACIDazolamide' causes acidosis
Local anesthetic.

35. List the specific antidote for this toxin: Opioids
Ibuprofen - Naproxen - and Indomethacin
Dermatophytes (tinea - ringworm)
- Steroids - Tamoxifen
- B51Naloxone / naltrexone (Narcan)

36. Ethacrynic Acid - clinical use?
anticholinesterase glaucoma
Rheumatoid and osteoarthritis.
Diuresis in pateints with sulfa allergy
Same as penicillin. Extended spectrum antibiotics

37. Foscarnet does not require activation by a...
Disulfiram - like reaction with EtOH - Headache
Blocks Influenza A and RubellA; causes problems with the cerebellA
Increase target cell response to insulin.
viral kinase

38. What enzyme is responsible for the production of Ach from Acetyl CoA and Choline
Prevents the release of ACh - Which results in muscle paralysis.
Choline acetyltransferase
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
H2 antagonist

39. What is the memory key for the effect of aluminum hydroxide overuse?
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
AluMINIMUM amount of feces.
first dose orthostatic hypotension - dizziness - headache
Acts as a wide spectrum carbapenem

40. Which cancer drugs inhibit nucleotide synthesis(3)?
- Methotrexate - 5 FU - 6 mercaptopurine
1. Acarbose 2. Miglitol
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
thiazides - amiloride

41. Does Heparin have a long - medium - or short half life?
Short.
- Aminocaproic acid
Digitoxin>95% Digoxin 75%
1. Renal damage 2. Aplastic anemia 3. GI distress

42. What is the MOA for the Azoles?
Pentamidine
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
- Alkalates DNA - CML - Pulmonary fibrosis hyperpigmentation
Inhibit Ergosterol synthesis

43. MOA: Bactericidal antibiotics
AZT
Tricyclic antidepressant.
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole

44. What are Amantadine - associated side effects?
Ataxia - Dizziness - Slurred speech
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
cardiac depression - peripheral edema - flushing - dizziness - constipation
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.

45. Ibutilide - toxicity?
torsade de pointes
Diarrhea
- Estrogen receptor antagonist - Breast CA - increased endometrial CA risk
carbonic anhydrase inhibitors - K+ sparing diuretics

46. What physiological effects was the Anes using Atropine to tx
Mg = Must go to the bathroom.
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
aPTT (intrinsic pathway)
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)

47. What is the MOA for Acyclovir?
- Alkalate DNA - Brain tumors - CNS toxicity
Inhibit viral DNA polymerase
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
- Antipsychotics

48. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
Hypersensitivity reactions
No - hemicholinum block the uptake of Choline and thus Ach synthesis
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
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.

49. What is the category of drug names ending in - ane (e.g. Halothane)
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.)
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.
Inhalational general anesthetic.
decrease

50. List the mechanism - clinical use - & toxicity of Vincristine.

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