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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 the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
- Lithium
NO HYPERURICEMIA - NO SULFA AllERGY; same as furosemide otherwise
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping
Constant FRACTION eliminated per unit time.(exponential)

2. What is the effect of norepinephrine on bp and pulse pressure?
Increases mean - systolic - and diastolic bp - while there is little change in pulse pressure.
all except the K+ sparing diuretics Spironolactone - Triamterene - Amiloride
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone

3. Does Heparin have a long - medium - or short half life?
1. Mycobacterium tuberculosis 2. Delays resistance to Dapsone When used of Leprosy 3. Used in combination with other drugs
Hypokalemic metabolic alkalosis - hyponatremia - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia - sulfa allergy.
Short.
Hexamethonium is a nicotinic antagonist - and thus is a ganglionic blocker.

4. What are the indications for using amphetamine?

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5. What is the MOA for Trimethoprim (TMP)?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Clindamycin
Botulinum
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids

6. What is the enzyme inhibited - the effect of this inhibition - and the clinical use of the antiandrogren Finasteride?
Finasteride inhibits 5 Alpha - reductase - this decreases the conversion of testosterone to dihydrotestosterone - useful in BPH
Nephrotoxicity
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.
- Constant AMOUNT eliminated per unit time. - Etoh & ASA

7. Why are albuterol and terbutaline effective in tx of acute asthmatic attacks?
Dopamine
Blocks viral penetration/uncoating; may act to buffer the pH of the endosome
These B-2 agonists cause respiratory smooth muscle to relax.
Short.

8. Adverse effects of Hydralazine?
1.Gram - rods of the Urinary and GI tracts (including Pseudomonas) 2.Neisseria 3. Some Gram + organisms
collecting ducts
nausea - headache - lupus - like syndrome - reflex tachycardia - angina - salt retention
Neutropenia

9. Which cancer drugs work at the level of mRNA(2)?
Carbachol - pilocarpine - physostigmine - echothiophate
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
- Steroids - Tamoxifen

10. Which of epi - norepi - or isoproterenol results in bradycardia?
Norepinephrine
decrease conduction velocity - increase ERP - increase PR interval
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

11. What are Polymyxins used for?
Resistant Gram - infections
Quinolones
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Onchocerciasis ('river blindness'-- rIVER- mectin)

12. List the specific antidote for this toxin: Warfarin
- Tetracycline
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- Quinidine - quinine
- Vitamin K & fresh frozen plasma

13. What is the mecanism of action of the COX-2 inhibitors (celecoxib - rofecoxib)?
Same as penicillin. Extended spectrum antibiotics
cholestyramine - colestipol
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Diarrhea - Urination - Miosis - Bronchospasm - Bradycardia - Excitation of skeletal muscle and CNS - Lacrimation - Sweating - and Salivation = DUMBBELS; also abdominal cramping

14. In What population does Gray Baby Syndrome occur? Why?
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Premature infants - because they lack UDP- glucuronyl transferase
cardiac muscle: Verapamil>Diltiazem>Nifedipine
1. Pioglitazone 2. Rosiglitazone.

15. List the specific antidote for this toxin: Benzodiazepines
Inhibit Ergosterol synthesis
Hypersensitivity reactions
- Flumazenil
Beta antagonist.

16. List five common glucocorticoids.
1. Hydrocortisone 2. Predisone 3. Triamcinolone 4. Dexamethasone 5. Beclomethasone
Butyrophenone (neuroleptic).
Hemolytic anemia
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions

17. What is the MOA of Griseofulvin?
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
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.
Interferes with microtubule function - disrupts mitosis - inhibits growth
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.

18. Why would you use pralidoxime after exposure to an organophosphate?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
- Vinca alkaloids(inhibit MT) - Paclitaxel
Pralidoxime regenerates active cholinesterase.
Aminoglycosides

19. Loop diuretics (furosemide)- site of action?
thick ascending limb
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)
Verapamil - Diltiazem - Bepridil

20. What are three complications of Warfarin usage?
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
- Tetracycline
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions

21. Quinidine - toxicity?
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Saquinavir - Ritonavir - Indinavir - Nelfinavir

22. Why is pyridostigmine effective in the treatment of myasthenia gravis?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
Gram + and Anerobes
As an anticholinesterase it increases endogenous ACh and thus increases strength.
Inhibit intestinal bursh border Alpha - glucosidases; delayed hydrolysis of sugars and absorption of sugars leading to decresed postprandial hyperglycemia.

23. Which antimicrobials inhibit protein synthesis at the 50S subunit? (4)
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Epinephirine(Alpha1 -2 and Beta 1 -2)

24. Which drug(s) cause this reaction: Adrenocortical Insufficiency
- Glucocorticoid withdrawal
- Tricyclic antidepressants
HSV - VZV - EBV - Mucocutaneous and Genital Herpes Lesions - Prophylaxis in Immunocompromised pts
AluMINIMUM amount of feces.

25. Adverse effects of Prazosin?
very short acting
first dose orthostatic hypotension - dizziness - headache
penicillinase resistant
Praziquantel

26. Which drug(s) cause this reaction: Gynecomastia (6)?
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Reversible block of histamine H2 receptors
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.

27. What is the category - desired effect - and period of use of albuterol in the treatment of Asthma?
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Digitoxin 168hrs Digoxin 40 hrs
Succinylcholine

28. What is the clinical use for Nystatin?
Scopolamine
Topical and Oral - for Oral Candidiasis (Thrush)
Blocking muscarinic receptors in the circular fibers of the eye - results in unopposed action of radial muscles to dilate.
Prevention of NSAID- induced peptic ulcers - maintains a PDA.

29. What is the mechanism of action of NSAIDs other than Aspirin?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
- Physostigmine salicylate
Pralidoxime regenerates active cholinesterase.
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.

30. What is the MOA for Metronidazole?
Disulfiram - like reaction with EtOH - Headache
Forms toxic metabolites in the bacterial cell - Bactericidal
Polymyxin B - Polymyxin E
is resistant

31. What cholinomimetic is useful in the diagnosis of Myasthenia Gravis
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Digitoxin>95% Digoxin 75%
Edrophonium
- Glucocorticoid withdrawal

32. What are three possible toxicities of NSAID usage?
1. Renal damage 2. Aplastic anemia 3. GI distress
Gram + - Gram - - Norcardia - Chlamydia
Recurrent UTIs - Shigella - Salmonella - Pneumocystis carinii pneumonia
- Physostigmine salicylate

33. For Heparin What is the Treatment for overdose
Protamine sulfate
- Methylene blue
For serious - Gram + multidrug - resistant organisms
- Acetaldehyde - Nausea - vomiting - headache - & hypotension

34. Verapamil has similar action to?
Nephrotoxicity
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
Albuterol - tertbutaline
Beta Blockers

35. For Heparin What is the Onset of action
AV nodal cells
Rapid (seconds)
Blocks Influenza A and RubellA; causes problems with the cerebellA
Clavulanic acid

36. Clinical use of Isoniazid (INH)?
TMP- SMZ
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Antileukotriene; blocks synthesis by lipoxygenase.
Topical and Oral - for Oral Candidiasis (Thrush)

37. Procainamide - toxicity?
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
Lovastatin - Pravastatin - Simvastatin - Atorvastatin
reversible SLE- like syndrome

38. What is treated with Chloroquine - Quinine - Mefloquine?
- Atropine & pralidoxime
AluMINIMUM amount of feces.
Malaria (P. falciparum)
- Penicillin

39. What are two Alpha - glucosidase inhibitors?
hypertension - CHF - diabetic renal disease
1. Acarbose 2. Miglitol
Carbachol - pilocarpine - physostigmine - echothiophate
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.

40. Which Aminoglycoside is used for Bowel Surgery ?
CMV Retinitis in IC pts When Ganciclovir fails
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Neomycin

41. How does botulinum toxin result in respiratory arrest?
hypokalemia - slight hyperlipidemia - hyperuricemia - lassitude - hypercalcemia - hyperglycemia
Useful in muscle paralysis during surgery or mechanical ventilation.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Prevents the release of ACh - Which results in muscle paralysis.

42. Acetazolamide - site of action?
proximal convoluted tubule
NO
AmOxicillin has greater Oral bioavailability
Aminoglycosides

43. Common toxicities associated with Griseofulvin?
Those patients who are taking nitrates.
Teratogenic - Carcinogenic - Confusion - Headaches
- NaHCO3
ACIDazolamide' causes acidosis

44. Which drug(s) cause this reaction: P450 induction(6)?
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Sulfamethoxazole (SMZ) - Sulfisoxazole - Triple sulfas - Sulfadiazine
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

45. Resistance mechanisms for Cephalosporins/Penicillins
Beta - lactamase cleavage of Beta - lactam ring
Indirect agonist - uptake inhibitor
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
- Alkalating agent - testicular - bladder - ovary -& lung - Nephrotoxicity & CN VIII damage.

46. What is the MOA for the Cephalosporins?
Tendonitis and Tendon rupture
Inhibits organification and coupling of thyroid hormone synthesis. Also decreases peripheral conversion of T4 to T3.
Beta lactams - inhibit cell wall synthesis - Bactericidal
Due to the presence of a bulkier R group

47. Antiarrhythmic Class III- effects?
Beta Blockers
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
Interferes with microtubule function - disrupts mitosis - inhibits growth
Irreversibly inhibits H+/K+ ATPase in stomach parietal cells.

48. Why are the Sulfonylureas inactive in IDDM (type -1)?
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
Because they require some residual islet function.
Selectively inhibit cyclooxygenase (COX) isoform 2 - Which is found in inflammatory cells nad mediates inflammation and pain; spares COX-1 Which helps maintain the gastric mucosa.
Polymyxin B - Polymyxin E

49. What are common side effects of Amphotericin B?
RESPIre
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Disulfiram - like reaction with EtOH - Headache
Inhibits Viral DNA polymerase

50. What is the MOA for Ampicillin and Amoxicillin?
Same as penicillin. Extended spectrum antibiotics
Bismuth and Amoxicillin or Tetracycline; against Helobacter pylori
-100% oxygen - hyperbaric
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.