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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 microorganisms are clinical indications for Tetracycline therapy?

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2. List the specific antidote for this toxin: Cyanide
YES
- Nitrate - hydroxocobalamin thiosulfate
Triple Therapy' 2 Nucleoside RT Inhibitors with a Protease Inhibitor
Slow - limited by half lives of clotting factors

3. Describe first - order kinetics?
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Local anesthetic.
Constant FRACTION eliminated per unit time.(exponential)
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

4. For Warfarin What is the Duration of action
Pituitary hormone.
Antileukotriene; blocks synthesis by lipoxygenase.
fetal renal toxicity - hyperkalemia
Chronic (weeks or months)

5. Are Ampicillin and Amoxicillin are not...
penicillinase resistant
Blocks Peptide Bond formation at the 50S subunit - Bacteriostatic
Gram + - Gram - - Norcardia - Chlamydia
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes

6. What enzymes are inhibited by NSAIDs - acetaminophen and COX II inhibitors?
Indirect agonist - uptake inhibitor
Saquinavir - Ritonavir - Indinavir - Nelfinavir
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
Cyclooxygenases (COX I - COX II).

7. Adverse effects of Nifedipine - verapamil?
Inhibits cell wall mucopeptide formation - Bactericidal
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
- Isoniazid
dizziness - flushing - constipation (verapamil) - nausea

8. What should not be taken with Tetracyclines? / Why?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
- Shifts the curve down - reduces Vmax
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Milk or Antacids - because divalent cations inhibit Tetracycline absorption in the gut

9. List the specific antidote for this toxin: Opioids
anuria - CHF
- Niacin - Ca++ channel blockers - adenosine - vancomycin
- B51Naloxone / naltrexone (Narcan)
Intrathecally

10. Steady state concentration is reached in __ number of half - lifes
Large anionic polymer - acidic
Rheumatoid and osteoarthritis.
Digoxin=urinary Digitoxin=biliary
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

11. 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
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
- Flumazenil
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Norepinephrine (Alpha1 -2 and beta 1)

12. Common side effects associated with Clindamycin include?
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
Pseudomembranous colitis (C. difficile) - fever - diarrhea
decrease
- Atropine & pralidoxime

13. What are five advantages of Oral Contraceptives (synthetic progestins - estrogen)?
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
Inhibit DNA Gyrase (topoisomerase II) - Bactericidal
is resistant
- Glucagon

14. What is the category of drug names ending in - cycline (e.g. Tetracycline)
- Chloramphenicol
Atropine would also block the receptors in the ciliary muscle - causing an impairment in accommodation (cycloplegia).
Antibiotic - protein synthesis inhibitor.
Tendonitis and Tendon rupture

15. Antiarrhythmic class IB- effects?
torsade de pointes
Delirium - Tremor - Nephrotoxicity
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

16. Side effects of Isoniazid (INH)?
DOC in diagnosing and abolishing AV nodal arrhythmias
NO
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Binds to the Pyrophosphate Binding Site of the enzyme

17. What are the clinical uses for 3rd Generation Cephalosporins?
- Phenytoin
Chronic Hepatitis A and B - Kaposi's Sarcoma
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Beta -2 agonist.

18. What is the MOA of Isoniazid (INH)?
Because they require some residual islet function.
Increases coumadin metabolism
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Decreases synthesis of Mycolic Acid

19. Antiarrhythmic class IV- effects?
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.
decrease conduction velocity - increase ERP - increase PR interval
- Corticosteroids - heparin

20. What type of neurological blockade would hexamethonium create?
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.
sedation - sleep alterations
loop diuretics - thiazides
- Fluoroquinolones

21. What is the mechanism of action of the Alpha - glucosidase inhibitors?
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
cross - allergenic
Paranteral (IV - SC)

22. Name the common Fluoroquinolones (6)
H2 antagonist
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
proximal convoluted tubule - thin descending limb - and collecting duct
Ibuprofen - Naproxen - and Indomethacin

23. What is a Ribavirin toxicity?
Hemolytic anemia
WEPT: Warfarin affects the Extrinsic pathway and prolongs the PT.
TCA
Tubocurarine - atracurium - mivacurium - pancuronium - vecuronium - rapacuronium

24. Foscarnet toxicity?
Constant FRACTION eliminated per unit time.(exponential)
Nephrotoxicity
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
- Bleomycin - amiodarone - busulfan

25. Antiarrhythmic class II- mechanism?
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
-100% oxygen - hyperbaric
Aminoglycosides

26. List the specific antidote for this toxin: Carbon monoxide
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Hypersensitivity reactions
-100% oxygen - hyperbaric
The COX-2 inhibitors should not have the corrosive effects of other NSAIDs on the gastrointestinal lining.

27. Describe the MOA of Interferons (INF)
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Acts as a wide spectrum carbapenem
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

28. What is the MOA for Nystatin?
Binds ergosterol - Disrupts fungal membranes
- Corticosteroids - heparin
sedation - sleep alterations
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia

29. How can Isoniazid (INH)- induced neurotoxicity be prevented?
- Dimercaprol - succimer
Modification via Acetylation - Adenylation - or Phosphorylation
Treatment of hypertension - especially with renal disease (lowers bp centrally - so flow is maintained to kidney).
Pyridoxine (B6) administration

30. Describe Phase I metabolism in liver(3)?
Carbenicillin - Piperacillin - and Ticarcillin
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Pituitary hormone.
- Methylene blue

31. Bretyllium - toxicity?
anticholinesterase glaucoma
- Cloazapine - carbamazapine - colchicine - PTU
- EDTA - dimercaprol - succimer - & penicillamine
new arrhythmias - hypotension

32. Why would you give a drug like pancuronium or succinylcholine?
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Useful in muscle paralysis during surgery or mechanical ventilation.
Lovastatin - Pravastatin - Simvastatin - Atorvastatin

33. What is the category of drug names ending in - tidine (e.g. Cimetidine)
TCA
fetal renal damage - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.
H2 antagonist

34. What is the mecanism of action - effective period - and ineffective period of use for Cromolyn in treating Asthma?
Warfarin interferes with the normal synthesis and gamma - carboxylation of vitamin K- dependent clotting factors II - VII - IX - and X - Protein C and S via vitamin K antagonism.
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Zidovudine (AZT) - Didanosine (ddI) - Zalcitabine (ddC) - Stavudine (d4T) - Lamivudine (3TC)
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.

35. What are four conditions in Which H2 Blockers are used clinically?
- Tetracycline - amiodarone - sulfonamides
Prevents the release of Ca from SR of skeletal muscle
Leukotrienes increasing bronchial tone.
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

36. Antiarrhythmic class IV- primary site of action?
AV nodal cells
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
Md= (CpxCL)/F Cp= plas. Conc. CL=clear. F=bioaval.
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia

37. Ethacrynic Acid - clinical use?
Teratogenic - Carcinogenic - Confusion - Headaches
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
Diuresis in pateints with sulfa allergy
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

38. Resistance mechanisms for Tetracycline
Decreased uptake or Increased transport out of cell
- Corticosteroids - heparin
1. Gastric ulceration 2. Bleeding 3. Hyperventilation 4. Reye's syndrome 5. Tinnitus (CN VIII)
None. No - because atropine would block the postganglionic muscarinic receptors involved in sweat gland stimulation.

39. What drug is given for Pneumocystis carinii prophylaxis?
Pentamidine
edematous states (CHF - cirrhosis - nephrotic syndrome - pulm edema) - HTN - hypercalcemia
Chronic anticoagulation.
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

40. How would hemicholinium treatment affect cholinergic neurons?
Hydralazine and Minoxidil
Pituitary hormone.
Hemicholinium inhibits the transport of choline into the nerve - thus inhibiting formation of ACh.
Norepinephrine

41. Hydrochlorothiazide - mechanism?
IV vitamin K and fresh frozen plasma
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.)
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.

42. What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
- Clindamycin
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
Useful in muscle paralysis during surgery or mechanical ventilation.
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

43. What is the mechanism of Leuprolide?
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
Rifampin
- Act on same receptor - Full has greater efficacy
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

44. What are three types of antacids and the problems that can result from their overuse?
Ganciclovir is more toxic to host enzymes
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
- inhibits HGPRT (pur. Syn.) - Luk - Lymph
1. Aluminum hydroxide: constipation and hypophosphatemia 2. Magnesium hydroxide: diarrhea 3. Calcium carbonate: Hypercalcemia - rebound acid increase - All may cause hypokalemia

45. Where does Griseofulvin deposit?
- Methotrexate - 5 FU - 6 mercaptopurine
is resistant
Keratin containing tissues - e.g. - nails
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances

46. Which drug(s) cause this reaction: Tardive dyskinesia?
- Antipsychotics
cholestyramine - colestipol
Inhibits reabsorption of uric acid.
Megaloblastic anemia - Leukopenia - Granulocytopenia

47. Which diuretics increase urine NaCl?
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
1. Pioglitazone 2. Rosiglitazone.
all of them
Neomycin

48. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Modification via Acetylation
- Disulfram & also sulfonylureas - metronidazole
carbonic anhydrase inhibitors - K+ sparing diuretics

49. When is Rifampin not used in combination with other drugs?
It must be Phosphorylated by Viral Thymidine Kinase
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Foscarnet = pyroFosphate analog
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.

50. What is the MOA for the Azoles?
Inhibit Ergosterol synthesis
hyperaldosteronism - K+ depletion - CHF
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
Methylxanthine.