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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. What are are the Sulfonylureas (general description) and What is their use?
INH: Injures Neurons and Hepatocytes
Treatment of infertility.
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

2. Which antimuscarinic agents are used in producing mydriasis and cycloplegia?
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
atropine - homatropine - tropicamide

3. Norepi feedbacks and inhibits the presynaptic receptor by What mechanism
GI upset - Superinfections - Skin rashes - Headache - Dizziness
Binding to the presynaptic alpha 2 release modulating receptors
- Protamine
Methylation of rRNA near Erythromycin's ribosome binding site

4. What are common toxic side effects of Sulfonamides? (5)
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.

5. What are the side effects of Polymyxins?
Butyrophenone (neuroleptic).
G6PD deficient individuals
Neurotoxicity - Acute renal tubular necrosis
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

6. Guanethidine enhances the release of Norepi?
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
No - it inhibits the release of Nor Epi
Increases coumadin metabolism

7. What is the clinical use of Tacrolimus (FK506)?
Inhibits CMV DNA polymerase
Potent immunosuppressive used in organ transplant recipients.
Dopamine
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.

8. Which diuretics cause acidosis?
Methicillin - Nafcillin - and Dicloxacillin
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
carbonic anhydrase inhibitors - K+ sparing diuretics
Ipratropium

9. A 57 yo heart failure pt develops cardiac decompensation - What drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
Pentavalent Antimony
- Oral Contraceptives
Phosphorylation by a Viral Kinase
Dopamine

10. How is Ganciclovir activated?
Amphetamine and Ephedrine
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Phosphorylation by a Viral Kinase
Foscarnet = pyroFosphate analog

11. What is the MOA for Methicillin - Nafcillin - and Dicloxacillin?
Foscarnet = pyroFosphate analog
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.
Same as penicillin. Act as narrow spectrum antibiotics

12. How would you reverse the effect of a neuromuscular blocking agent?
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.
Give an antichloinesterase - neostigmine - edrophonium - etc
Close K+ channels in Beta - cell membrane leading to cell depolarization causing insulin release triggered by increase in Calcium ion influx.
Prevents the release of Ca from SR of skeletal muscle

13. Explain pH dependent urinary drug elimination?
Antileukotriene; blocks leukotriene receptors.
Quinidine - Amiodarone - Procainamide - Disopyramide
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more
troponin - tropomyosin system

14. Beta Blockers - CV toxicity?
- Tricyclic antidepressants
AluMINIMUM amount of feces.
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.)
bradycardia - AV block - CHF

15. How does botulinum toxin result in respiratory arrest?
Prevents the release of ACh - Which results in muscle paralysis.
Flecainide - Encainide - Propafenone
CMV Retinitis in IC pts When Ganciclovir fails
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

16. A fellow passenger on a Carnival cruise ship looks pale and diaphoretic - What antimuscarinic agent would you give them?
Potent immunosuppressive used in organ transplant recipients.
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring
scopolamine
Primaquine

17. What process does Zafirlukast interfere with?
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
- Hydralazine - Procainamide - INH - phenytoin
Leukotrienes increasing bronchial tone.
Beta -2 agonist.

18. What are two conditions in Which COX-2 inhibitors might be used?
cardiac depression - peripheral edema - flushing - dizziness - constipation
Rapid (seconds)
Rheumatoid and osteoarthritis.
Minor hepatotoxicity - Drug interactions (activates P450)

19. Resistance mechanisms for Tetracycline
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
- Cloazapine - carbamazapine - colchicine - PTU
TCA
Decreased uptake or Increased transport out of cell

20. How can the t1/2 of INH be altered?
Fast vs. Slow Acetylators
Chronic (weeks or months)
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction
Short.

21. Name the common Nucleoside Reverse Transcriptase Inhibitors
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Rifampin (DOC) - minocycline
Inhibits reabsorption of uric acid.

22. What is the clinical use for Clomiphene?
Treatment of infertility.
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
YES
- Daunorubicin & Doxorubicin

23. Which drug(s) cause this reaction: Pseudomembranous colitis?
Amphetamine and Ephedrine
- Penicillamine
- Clindamycin
As an anticholinesterase it increases endogenous ACh and thus increases strength.

24. What is the clincial use for Misoprostol?
Prevention of NSAID- induced peptic ulcers - maintains a PDA.
- Deferoxamine
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Cyclooxygenases (COX I - COX II).

25. Common side effects associated with Clindamycin include?
Epinephirine(Alpha1 -2 and Beta 1 -2)
Cephalosporins
Pseudomembranous colitis (C. difficile) - fever - diarrhea
Tendonitis and Tendon rupture

26. What is the MOA of Imipenem?
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Binding to the presynaptic alpha 2 release modulating receptors
Acts as a wide spectrum carbapenem
For serious - Gram + multidrug - resistant organisms

27. What is the category of drug names ending in - oxin (e.g. Digoxin)
Acetylcholinesterase; ACh is broken down into choline and acetate.
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Cardiac glycoside (inotropic agent).
Initially vasoconstriction would increase bp - but then it acts on central alpha -2 receptors to decrease adrenergic outflow resulting in decreased bp.

28. What is the category - method of use - and adverse effects of Salmeterol in Asthma treatment?
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
Aminoglycosides - Tetracyclines
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
Inhibition of 50S peptidyl transferase - Bacteriostatic

29. When is HIV therapy initiated?
When pts have Low CD4+ (< 500 cells/cubic mm) or a High Viral Load
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
Mebendazole/Thiabendazole - Pyrantel Pamoate
RESPIre

30. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
Inhibits cell wall mucopeptide formation - Bactericidal
Praziquantel
Beta 2 agonist; used as a long - acting agent for prophylaxis. Adverse effects are tremor and arrhythmia.
- Flumazenil

31. What is the clinical use for Heparin?
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Interferes with microtubule function - disrupts mitosis - inhibits growth
Pentamidine
Immediate anticoagulation for PE - stroke - angina - MI - DVT.

32. 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
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity

33. Why is reserpine effective in treating HTN?
No. Atropine is used to reduce urgency in mild cystitis. So it would aggravate the urinary retention.
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
Intrathecally

34. What are two indirect acting adrenergic agonists?
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
amphetamine and ephedrine
Flecainide - Encainide - Propafenone
- Haloperidol - chlorpromazine - reserpine - MPTP

35. What is the MOA for the Macrolides?
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.
Local anesthetic.
distal convoluted tubule (early)
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic

36. Adverse effects of Hydrochlorothiazide?
1. Weight gain 2. Hepatotoxicity (troglitazone)
distal convoluted tubule (early)
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
INH: Injures Neurons and Hepatocytes

37. Can Warfarin be used during pregnancy?
No - warfarin - unlike heparin - can cross the placenta.
loop diuretics - spironolactone
Those patients who are taking nitrates.
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)

38. What are nine findings of Iatrogenic Cushing's syndrome caused by glucocorticoid therapy?
Aminoglycosides
Prevents the release of ACh - Which results in muscle paralysis.
PT
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

39. What is the MOA for Acyclovir?
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
Inhibit viral DNA polymerase
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
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

40. Which drug(s) cause this reaction: Drug induced Parkinson's (4) ?
- Haloperidol - chlorpromazine - reserpine - MPTP
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
No - warfarin - unlike heparin - can cross the placenta.

41. What are four unwanted effects of Clomiphene use?
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
Oral
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Beta - lactamase cleavage of Beta - lactam ring

42. For Warfarin What is the Treatment for overdose
Decreased uptake or Increased transport out of cell
IV vitamin K and fresh frozen plasma
Mg = Must go to the bathroom.
- Tamoxifen

43. Hydrochlorothiazide - clinical use?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Dopamine; causes its release from intact nerve terminals
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
HTN - CHF - calcium stone formation - nephrogenic DI.

44. What is combined with Ampicillin - Amoxicillin - Carbenicillin - Piperacillin - and Ticarcillin to enhance their spectrum?
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
Clavulanic acid
Increases coumadin metabolism
Chronic anticoagulation.

45. ACE inhibitors - toxicity?
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Pyridoxine (B6) administration
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine

46. What is a common side effect of Misoprostol?
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis
local anesthetic. CNS stimulation or depression. CV depression.
Diarrhea

47. Hydrochlorothiazide - mechanism?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
cyanide toxicity (releases CN)
AZT - to reduce risk of Fetal Transmission
Blocks Influenza A and RubellA; causes problems with the cerebellA

48. How is Amantadine used clinically?

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49. Antimicrobial prophylaxis for Syphilis
Non - Nucleosides
Protamine sulfate
Neutropenia
Benzathine penicillin G

50. Which RT inhibitor causes Megaloblastic Anemia?
collecting ducts
proximal convoluted tubule
AZT
amphetamine and ephedrine