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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. Which cancer drugs work at the level of proteins(2)?
- Ammonium Chloride
Beta adrenergic receptors and Ca2+ channels (stimulatory)
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
- Vinca alkaloids(inhibit MT) - Paclitaxel

2. Thiazides - site of action?
distal convoluted tubule (early)
- Vinca alkaloids(inhibit MT) - Paclitaxel
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
troponin - tropomyosin system

3. What is the mechanism of action of Misoprostol?
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
- Ammonium Chloride
Only in limited amounts
1. Pioglitazone 2. Rosiglitazone.

4. What is an additional side effect of Methicillin?
Interstitial nephritis
Theoretically it could be used to block the cephalic phase of acid secretion (vagal stimulation).
- Isoniazid
H2 antagonist

5. For Heparin What is the Duration of action
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux
Large anionic polymer - acidic
Acute (hours)
Inhibit steroid synthesis - used in the treatment of polycystic ovarian syndrome to prevent hirsutism.

6. What parasitic condition is treated with Ivermectin?

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7. Clinical use of Isoniazid (INH)?
dizziness - flushing - constipation (verapamil) - nausea
Mycobacterium tuberculosis - the only agent used as solo prophylaxis against TB
diuretics - sympathoplegics - vasodilators - ACE inhibitors - Angiotensin II receptor inhibitors
- S- phase anti - metabolite folate analogue - Luk - Lymp - sarc - RA - & psoriasis / - Reversible myelosuppression

8. What is the MOA for Trimethoprim (TMP)?
Chronic Hepatitis A and B - Kaposi's Sarcoma
- Methotrexate - 5 FU - 6 mercaptopurine
- Protamine
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

9. Name two classes of drugs for HIV therapy
IV vitamin K and fresh frozen plasma
Protease Inhibitors and Reverse Transcriptase Inhibitors
- Cloazapine - carbamazapine - colchicine - PTU
Beta Blockers

10. What are three toxicities of Propylthiouracil?
Norepinephrine
Epinephrine to treat anaphylaxis. Also useful if you have open angle glaucoma - asthma - or hypotension.
- Tetracycline
1. Skin rash 2. Agranulocytosis (rare) 3. Aplastic anemia

11. What is the mechanism of action of Colchicine used to treat acute gout?
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Sildenafil fills the penis
Sulfonamides - Trimethoprim

12. Aztreonam is not usually...
toxic
- Flumazenil
TMP- SMZ (DOC) - aerosolized pentamidine
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

13. What is the category - mechanism of action - and particular use of beclomethasone and prednisone in Asthma treatment?
1. Addison's disease 2. Inflammation 3. Immune suppression 4. Asthma
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.)
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
cardiac muscle: Verapamil>Diltiazem>Nifedipine

14. What is the category - desired effect - and adverse effect of Isoproterenol in the treatment of Asthma?
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
Nonspecific beta - agonist; desired effect is the relaxation of bronchial smooth muscle (Beta 2). Adverse effect is tachycardia (Beta 1).
Sulfonamides - Trimethoprim
- Cimetidine - ketoconazole - spironolactone - digitalis - EtOH - estrogens

15. How is Amphotericin B administered for fungal meningitis?
Intrathecally
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.)
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Pentavalent Antimony

16. Which drug(s) cause this reaction: Pseudomembranous colitis?
- Clindamycin
Sildenafil fills the penis
Rheumatoid and osteoarthritis.
1. Bleeding 2. Teratogenicity 3. Drug - drug interactions

17. What is the MOA of the RT Inhibitors?
Decrease the production of leukotrienes and protaglandins by inhibiting phospholipase A2 and expression of COX-2.
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
Anaerobes
- Alkalate DNA - Brain tumors - CNS toxicity

18. A 12yo patient was treated for a reaction to a bee sting - What drug provides the best coverage of sympathomimetic receptors?
Succinylcholine
- Steroids - Tamoxifen
Epinephirine(Alpha1 -2 and Beta 1 -2)
- Metronidazole - certain cephalosporins - procarbazine - sulfonylureas

19. What is the mechanism of action of Sildenafil (Viagra)?
severe hypertension - CHF
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.
scopolamine
- Cimetidine - ketoconazole - grapefruit juice - erythromycin - INH - sulfonamides

20. Why is carbachol and pilocarpine useful in treatment of glaucoma?
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Prevents release of mediators from mast cells. Effective only for the prophylaxis of asthma. Not effective during an acute attack.
Norepinephrine (Alpha1 -2 and beta 1)
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)

21. How does resistance to Vancomycin occur?
- reduction - oxy - & hydrolysis - H2O sol. Polar product - P450
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
With an amino acid change of D- ala D- ala to D- ala D- lac
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.

22. Verapamil has similar action to?
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
1. Streptokinase 2. Urokinase 3. tPA (alteplase) - APSAC (anistreplase)
Beta Blockers
Penicillin - Cephalosporins - Vancomycin - Aminoglycosides - Fluoroquinolones - Metronidazole

23. MOA of Succinylcholine
Used in combination therapy with SMZ to sequentially block folate synthesis
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.)
- Chlorpromazine - thioridazine - haloperidol
Prevents the release of Ca from SR of skeletal muscle

24. What microorganisms is Aztreonam not effective against?
Gram + and Anerobes
GI distress - Tooth discoloration and Inhibition of bone growth in children - Fanconi's syndrome - Photosensitivity
Foscarnet = pyroFosphate analog
Topical and Oral - for Oral Candidiasis (Thrush)

25. What is the category of drug names ending in - tidine (e.g. Cimetidine)
Bacitracin - Vancomycin
H2 antagonist
- Sulfonamides - furosemide - methicillin - rifampin - NSAIDS (ex. ASA)
decrease conduction velocity - increase ERP - increase PR interval

26. Are Ampicillin and Amoxicillin are not...
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
penicillinase resistant
Receptors = D1=D2>beta>alpha - thus increasing heart rate (beta) and blood pressure (alpha vasoconstriction) while maintaining kidney perfusion (dopamine receptors)
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.)

27. What is action of insulin in the liver - in muscle - and in adipose tissue?
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.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
check PFTs - LFTs - and TFTs
- Disulfram & also sulfonylureas - metronidazole

28. What type of patient should not take Misoprostol and why?
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide
Chagas' disease - American Trypanosomiasis (Trypanosoma cruzi)
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Penicillin.

29. What are four conditions in Which H2 Blockers are used clinically?
Sulfonamide Loop Diuretic. Inhibits ion co - transport system of thick ascending loop. Abolishes hypertonicity of the medulla - thereby preventing concentration of the urine.
- Methylene blue
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome

30. What is the mechanism of action of Aspirin?
Acetylates and irreversibly inhibits cyclooxygenase (COX I and COX II) to prevent the conversion of arachidonic acid to prostaglandins.
1. Antipyretic 2. Analgesic 3. Anti - inflammatory
- Isoniazid
No - it inhibits the release of Nor Epi

31. Mannitol - toxicity?
pulmonary edema - dehydration
Chronic anticoagulation.
Amphetamine and Ephedrine
- Daunorubicin & Doxorubicin

32. What are two toxicities associated with Cyclosporine?
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Hypersensitivity reactions
1. Predisposes to viral infections and lymphoma 2. Nephrotoxic (preventable with mannitol diuresis)
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

33. Name the Protease Inhibitors (4)
Saquinavir - Ritonavir - Indinavir - Nelfinavir
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow
In 4 half - lifes= (94%) T1/2 = (0.7x Vd)/CL

34. What is the formula for Clearance (CL)
CL= (rate of elimination of drug/ Plasma drug conc.)
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Nevirapine - Delavirdine
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.

35. How does a noncompetitive antagonist effect an agonist?
- Upper respiratory tract infections - pneumonias - STDs: Gram+ cocci (streptococcal infect in pts allergic to penicillin) - Mycoplasma - Legionella - Chlamydia - Neisseria
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
- Shifts the curve down - reduces Vmax
compensatory tachycardia - fluid retention - lupus - like syndrome

36. What are the four conditions in Which Omeprazole - Lansoprazole is used?
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
Inhibit viral DNA polymerase
1. Peptic ulcer 2. Gastritis 3. Esophageal reflux 4. Zollinger - Ellison syndrome
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

37. Acetazolamide - toxicity?
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Early myocardial infarction.
hyperchloremic metabolic acidosis - neuropathy - NH3 toxicity - sulfa allergy
Methicillin - Nafcillin - and Dicloxacillin

38. ADH antagonists - site of action?
Interferes with microtubule function - disrupts mitosis - inhibits growth
Vd= (Amt. of drug in body/ Plasma drug conc.)
Staphlococcus aureus and Clostridium difficile (pseudomembranous colitis)
collecting ducts

39. Which diuretics increase urine NaCl?
post MI and digitalis induced arrhythmias
all of them
Epinephrine
Pseudomembranous colitis (C. difficile) - fever - diarrhea

40. Foscarnet does not require activation by a...
Neostigmine - pyridostigmine edrophonium - physostigmine echothiophate
Gram + cocci - Proteus mirabilis - E. coli - Klebsiella pneumoniae (PEcK)
viral kinase
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)

41. MOA: Block protein synthesis at 30s subunit
Aminoglycosides - Tetracyclines
Erythromycin - Azithromycin - Clarithromycin
Give an antichloinesterase - neostigmine - edrophonium - etc
- A57Blue lines in gingiva & long bones - Encephalopathy & Foot drop - Abdominal colic / - Sideroblastic anemia

42. What is the MOA of Aztreonam?
Inhibit viral DNA polymerase
Inhibits cell wall synthesis ( binds to PBP3). A monobactam
Doxycycline - because it is fecally eliminated
VACUUM your Bed Room'

43. K+ sparing diuretics - clinical use?
Same as penicillin. Act as narrow spectrum antibiotics
hyperaldosteronism - K+ depletion - CHF
TMP- SMZ
- Disulfram & also sulfonylureas - metronidazole

44. Ganciclovir associated toxicities?
- Bleomycin - amiodarone - busulfan
Leukopenia - Neutropenia - Thrombocytopenia - Renal toxicity
penicillinase resistant
torsade de pointes

45. What beta 2 agonist will help your 21yo Astma pt?
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
Albuterol - tertbutaline
Beta -2 agonist.
Benzathine penicillin G

46. Common toxicities associated with Griseofulvin?
Only in limited amounts
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
Teratogenic - Carcinogenic - Confusion - Headaches
- Airway - Breathing - Circulation - Dextrose (thiamine & narcan) - ABCD

47. Why is Cilastatin administered with Imipenem?
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
- Phase I (clinical tests) - Phase II - Phase III - PhaseIV (surveillance)
impotence - asthma - CV effects (bradycardia - CHF - AV block) - CNS effects (sedation - sleep alterations)
Paranteral (IV - SC)

48. Which drug(s) cause this reaction: Extrapyramidal side effects (3)?
Inhalational general anesthetic.
Binds 30S subunit and prevents attachment of aminoacyl - tRNA - Bacteriostatic
- Chlorpromazine - thioridazine - haloperidol
all of them

49. What is the clinical use of Mifepristone (RU486)?
Abortifacient.
Indirect agonist - uptake inhibitor
Impairs the synthesis of vitamin K- dependent clotting factors
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval

50. What are common toxic side effects of Sulfonamides? (5)
Yes - it does not cross the placenta.
- Hypersensitivity reactions - Hemolysis - Nephrotoxicity (tubulointerstitial nephritis) - Kernicterus in infants Displace other drugs from albumin (e.g. - warfarin)
Phenothiazine (neuroleptic - antiemetic).
- Protamine