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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. Adverse effects of Prazosin?
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.
first dose orthostatic hypotension - dizziness - headache
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression
Increased systolic and pulse pressure - decreased diastolic pressure - and little change in mean pressure.

2. Hydrochlorothiazide - clinical use?
HTN - CHF - calcium stone formation - nephrogenic DI.
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)

3. List the specific antidote for this toxin: Arsenic (all heavy metals)
Corticosteroids; prevent production of leukotrienes from arachodonic acid by blocking phospholipase A2. Drugs of choice in a patient with status asthmaticus (in combination with albuterol.)
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol
- Dimercaprol - succimer
- Protamine

4. Mannitol - mechanism?
osmotic diuretic - increase tubular fluid osmolarity - thereby increasing urine flow
Hypersensitivity reactions
Megaloblastic anemia - Leukopenia - Granulocytopenia
Neurotoxicity - Acute renal tubular necrosis

5. What is the clinical use of Tacrolimus (FK506)?
NE acts presynaptically on alpha -2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
vasodilator - increases cGMP to induce smooth muscle relaxation (arterioles>veins; afterload reduction)
Gram + - Gram - - Norcardia - Chlamydia
Potent immunosuppressive used in organ transplant recipients.

6. What is the category of drug names ending in - cillin (e.g. Methicillin)
AZT
Penicillin.
HTN - CHF - calcium stone formation - nephrogenic DI.
Beta lactams - inhibit cell wall synthesis - Bactericidal

7. Which diuretics decrease urine Ca2+?
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Inhibits DNA dependent RNA polymerase
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
thiazides - amiloride

8. K+- clinical use?
check PFTs - LFTs - and TFTs
1. Hot flashes 2. Ovarian enlargement 3. Multiple simultaneous pregnancies 4. Visual disturbances
depresses ectopic pacemakers - especially in digoxin toxicity
1. Pioglitazone 2. Rosiglitazone.

9. What is the category - mechanism of action - and effect of Ipratroprium in Asthma treatment?
Succinylcholine
- Formaldehyde & formic acid - severe acidosis & retinal damage
Minor hepatotoxicity - Drug interactions (activates P450)
Muscarinic antagonist; competatively blocks muscarinic receptors - preventing bronchoconstriction.

10. Furosemide - class and mechanism?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
Beta 2 agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Use during acute exacerbation.
Give an antichloinesterase - neostigmine - edrophonium - etc
Tricyclic antidepressant.

11. How is Leishmaniasis treated?
Doxycycline - because it is fecally eliminated
competitive inhibirot of aldosterone in the cortical collecting tubule
Lipoxygenase
Pentavalent Antimony

12. Describe the MOA of Interferons (INF)
GI discomfort - Acute cholestatic hepatitis - Eosinophilia - Skin rashes
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Quinolones
Glycoproteins from leukocytes that block various stages of viral RNA and DNA synthesis

13. Ethacrynic Acid - mechanism?
Beta - lactam antibiotics
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out - but the SA node has an intrinsic pace of 100 beats/min - Which is normally checked by vagal stimulation.
not a sulfonamide - but action is the same as furosemide
Slow - limited by half lives of clotting factors

14. What sympathomimetic would you not prescribe for hypotension in a pt with renal artery sclerosis.
- Shifts the curve to the right - increases Km
Choline acetyltransferase
Norepinephrine (Alpha1 -2 and beta 1)
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.

15. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
Prevents the release of Ca from SR of skeletal muscle
Penicillin.
The PT.
Same as penicillin. Extended spectrum antibiotics

16. How do Sulfonamides act on bacteria?
- Glucocorticoid withdrawal
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
PT
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state

17. Which drug(s) cause this reaction: Fanconi's syndrome?
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
1. RNA pol inhibitor 2. Revs up P450 3. Red/orange body fluids 4. Rapid resistance if used alone
- Tetracycline
1. Antipyretic 2. Analgesic 3. Anti - inflammatory

18. Guanethidine enhances the release of Norepi?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
Succinylcholine
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
No - it inhibits the release of Nor Epi

19. Beta Blockers - BP?
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased
- DNA intercalator - testicular & lymphomas - Pulmonary fibrosis mild myelosuppression.
Spironolactone - Triamterene - Amiloride (the K+ STAys)
decrease

20. Toxicities associated with Acyclovir?
Delirium - Tremor - Nephrotoxicity
Acts as a wide spectrum carbapenem
Terminal D- ala of cell wall replaced with D- lac; Decreased affinity
Chronic gout.

21. K+ sparing diuretics - site of action?
They inhibit reuptake of NE at the nerve terminal (as does cocaine).
Modification via Acetylation
cortical collecting tubule
Digitoxin 168hrs Digoxin 40 hrs

22. For Warfarin What is the Onset of action
Slow - limited by half lives of clotting factors
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic
Keratin containing tissues - e.g. - nails
Dopamine; causes its release from intact nerve terminals

23. What is the mechanism of Tacrolimus (FK506)?
Clomiphene is a partial agonist at estrogen receptors in the pituitary gland. Prevents normal feedback inhibition and increses release of LH and FSHfrom the pituitary - Which stimulates ovulation.
Erythromycin - Azithromycin - Clarithromycin
is resistant
Similar to cyclosporine; binds to FK- binding protein - inhibiting secretion of IL-2 and other cytokines.

24. Adverse effects of Guanethidine?
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
thiazides - amiloride
distal convoluted tubule (early)
Oxygen

25. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
Beta Blockers
Methylxanthine.
- Ethosuxamide - sulfonamides - lamotrigine
cardiac muscle: Verapamil>Diltiazem>Nifedipine

26. Why are the Sulfonylureas inactive in IDDM (type -1)?
Because they require some residual islet function.
new arrhythmias - hypotension
CMV - esp in Immunocompromised patients
Interferes with microtubule function - disrupts mitosis - inhibits growth

27. Explain potency in relation to full and partial agonists(2).
increase AP duration - increase ERP - increase QT interval - for use When other arrhythmics fail
GET on the Metro
decrease conduction velocity - increase ERP - increase PR interval
- partial agonist can have increased - decreased - /A21or equal potency as full agonist. - Potency is an independent factor.

28. What is the MOA of Polymyxins?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Gentamicin - Neomycin - Amikacin - Tobramycin - Streptomycin

29. What is the category of drug names ending in - oxin (e.g. Digoxin)
Short.
Penicillin - Ampicillin - Ticarcillin - Pipercillin - Imipenem - Aztreonam - Cephalosporins
Cardiac glycoside (inotropic agent).
1. Better bioavailability 2. 2 to 4 times longer half life 3. Can be administered subcutaneously 4. Does not require laboratory monitoring

30. What is the effect of the Glitazones in diabetes treatment?
- NaHCO3
Hemolysis (if G6PD deficient) - Neurotoxicity - Hepatotoxicity - SLE- like syndrome
Antifungal.
Increase target cell response to insulin.

31. What are the clinical uses for 3rd Generation Cephalosporins?
GI disturbances.
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
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.
Because they require some residual islet function.

32. What is the clinical use for Ampicillin and Amoxicillin?
competitive inhibirot of aldosterone in the cortical collecting tubule
torsade de pointes
Extended spectrum penicillin: certain Gram + bacteria and Gram - rods
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

33. Which drug(s) cause this reaction: SLE- like syndrome?
- Hydralazine - Procainamide - INH - phenytoin
Benzodiazepine.
Methylzanthine; desired effect is bronchodilation - may cause bronchodilation by inhibiting phosphodiesterase - enzyme involved in degrading cAMP (controversial).
hypertension - angina - arrhythmias

34. What is the clinical use for Clomiphene?
1. Renal damage 2. Aplastic anemia 3. GI distress
Antileukotriene; blocks synthesis by lipoxygenase.
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.
Treatment of infertility.

35. Foscarnet toxicity?
- Act on same receptor - Full has greater efficacy
Nephrotoxicity
Cryptococcal meningitis in AIDS patients and Candidal infections of all types
Rifampin (DOC) - minocycline

36. What are four Sulfonylureas?
Modification via Acetylation - Adenylation - or Phosphorylation
With an amino acid change of D- ala D- ala to D- ala D- lac
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Hypersensitivity reactions

37. What is the difference between the affinity for beta receptors between albuterol/terbutaline and dantroline?
- Ethosuxamide - sulfonamides - lamotrigine
Rheumatoid and osteoarthritis.
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.
cardiac muscle: Verapamil>Diltiazem>Nifedipine

38. Which drug(s) cause this reaction: Agranulocytosis (3)?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
SLUD (salivation - Lacrimation - urination - Defecation)as well as airway secretion - GI motility - acid secretions
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
- Cloazapine - carbamazapine - colchicine - PTU

39. Which drug(s) cause this reaction: Tardive dyskinesia?
- Infections - Trauma - Seizures - CO - Overdose - Metabolic - Alcohol (IT'S COMA)
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
- Glucocorticoid withdrawal
- Antipsychotics

40. Which Tetracycline is used in patients with renal failure? / Why?
GET on the Metro
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Doxycycline - because it is fecally eliminated
pulmonary edema - dehydration

41. What is Clindamycin used for clinically?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Chronic (weeks or months)
- Lithium
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450

42. Hydralazine - clinical use?
blocks SR Ca2+ channels
severe hypertension - CHF
Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma pneumoniae Borrelia burgdorferi (Lyme's) Rickettsia Tularemia
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

43. What do Aminoglycosides require for uptake?
pulmonary edema - dehydration
Oxygen
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
Beta - lactamase cleavage of Beta - lactam ring

44. What is the category of drug names ending in - triptyline (e.g. Amitriptyline)
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.)
Stimulates beta adrenergic receptors
Amphotericin B - Nystatin - Fluconazole/azoles
Tricyclic antidepressant.

45. Resistance mechanisms for Macrolides

46. Which drug(s) cause this reaction: Hot flashes?
- Tamoxifen
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
Same as penicillin. Extended spectrum antibiotics
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal

47. Classes of antihypertensive drugs?
Reversibly inhibit cyclooxygenase (COX I and COX II). Block prostaglandin synthesis.
Nevirapine - Delavirdine
Staphlococcus aureus
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors

48. What is the MOA for Trimethoprim (TMP)?
Binds to cyclophilins (peptidyl proline cis - trans isomerase) - blocking the differentiation and activation of T cells mainly by inhibiting the production of IL-2 and its receptor.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic
Saquinavir - Ritonavir - Indinavir - Nelfinavir
Does not cross

49. Acetazolamide - toxicity?
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
As PABA antimetabolites that inhibit Dihydropteroate Synthase - Bacteriostatic
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
- Formaldehyde & formic acid - severe acidosis & retinal damage

50. What is clinical use for Carbenicillin - Piperacillin - and Ticarcillin?
Polymyxin B - Polymyxin E
Pseudomonas species and Gram - rods
Hormone synthesis inhibition (Gynecomastia) - Liver dysfunction (Inhibits CYP450) - Fever - Chills
severe orthostatic hypotension - blurred vision - constipation - sexual dysfunction