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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.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. Common toxicities associated with Griseofulvin?
Digoxin=urinary Digitoxin=biliary
Na/K ATPase
Teratogenic - Carcinogenic - Confusion - Headaches
Inhibits cGMP phosphodiesterase - casuing increased cGMP - smooth muscle relaxation in the corpus cavernosum - increased blood flow - and penile erection.

2. Secretion of What drug is inhibited by Probenacid used to treat chronic gout?
It inhibits release of NE.
Penicillin.
Triple sulfas or SMZ
Prophylaxis for Influenza A - Rubella; Parkinson's disease

3. For Heparin What is the Site of action
Short.
- Normalize K+ - Lidocaine - & Anti - dig Mab
dizziness - flushing - constipation (verapamil) - nausea
Blood

4. Esmolol - short or long acting?
Edrophonium
Reversible block of histamine H2 receptors
Long.
very short acting

5. What is the MOA of Polymyxins?
Inhibits NaCl reabsorption in the early distal tubule. Decreases Ca2+ excretion.
1. Heavy bleeding 2. GI effects (n/v - anorexia) 3. Abdominal pain
Binds to the Pyrophosphate Binding Site of the enzyme
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents

6. Which diuretics decrease urine Ca2+?
Nevirapine - Delavirdine
thiazides - amiloride
- Halothane - Valproic acid - acetaminophen - Amantia phalloides
very short acting

7. Adverse effects of Captopril?
- Quinidine - quinine
It affects beta receptors equally and is used in AV heart block (rare).
Cimetidine is a potent inhibitor of P450; it also has an antiandrogenic effect and decreases renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
fetal renal toxicity - hyperkalemia - Cough - Angioedema - Proteinuria - Taste changes - hypOtension - Pregnancy problems - Rash - Increased renin - Lower Angiotensin II (CAPTOPRIL)

8. How are the HIV drugs used clinically?

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9. What are common toxicities associated with Tetracyclines?

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10. Ca2+ channel blockers - clinical use?
- Vinca alkaloids(inhibit MT) - Paclitaxel
Inhibits platelet aggregation by irreversibly inhibiting the ADP pathway involved in the binding of fibrinogen.
Stimulates beta adrenergic receptors
hypertension - angina - arrhythmias

11. What are the clinical indications for bethanechol?
Activates cholinergic receptors on bladder and bowel smooth muscle - alleviating post - op and neurogenic ileus and urinary retention.
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- Act on same receptor - Full has greater efficacy
Beta adrenergic receptors and Ca2+ channels (stimulatory)

12. Adverse effects of Minoxidil?
- Class III antiarrhythmics (sotalol) - class IA (quinidine)
1. Infertility (pulsatile) 2. Prostate cancer (continuous: use with flutamide) 3. Uterine fibroids
1. Antiandrogen 2. Nausea 3. Vomiting
hypertrichosis - pericardial effusion - reflex tachycardia - angina - salt retention

13. What is the lab value used to monitor the effectiveness of Heparin therapy?
Prefers beta's at low doses - but at higher doses alpha agonist effects are predominantly seen.
The PTT.
Inhalational general anesthetic.
Ibuprofen - Naproxen - and Indomethacin

14. How do spare receptors effect the Km?
Gemfibrozil - Clofibrate
Chronic Hepatitis A and B - Kaposi's Sarcoma
- ED 50 is less than the Km (less than 50% of receptors)
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).

15. For Warfarin What is the Lab value to monitor
Modification via Acetylation
PT
cinchonism: HA - tinnitus - thrombocytopenia - torsade de pointes due to increased QT interval
Sulfonylureas are oral hypoglycemic agents - they are used to stimulate release of endogenous insulin in NIDDM (type -2).

16. How do the Protease Inhibitors work?
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
Inhibt Assembly of new virus by Blocking Protease Enzyme
Oral treatment of superficial infections
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.

17. What is the category of drug names ending in - olol (e.g. Propranolol)
Praziquantel
Beta antagonist.
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
TCA

18. Decrease Digoxin dose in renal failure?
Blocks translocation - binds to the 23S rRNA of the 50S subunit - Bacteriostatic
collecting ducts
Erectile dysfunction.
YES

19. List the mechanism - clinical use - & toxicity of Etoposide.
Diuresis in pateints with sulfa allergy
1. Significant: nephrotoxicity 2. Peripheral neuropathy 3. Hypertension 4. Pleural effusion 5. Hyperglycemia.
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.

20. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
decrease AP duration - affects ischemic or depolarized Purkinje and ventricular system
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
- Weak Acids>Alkinalize urine(CO3) to remove more - Weak bases>acidify urine to remove more

21. What are two conditions in Which COX-2 inhibitors might be used?
Minor hepatotoxicity - Drug interactions (activates P450)
Rheumatoid and osteoarthritis.
- Vinca alkaloids(inhibit MT) - Paclitaxel
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

22. Name three calcium channel blockers?
Cardiac glycoside (inotropic agent).
With an amino acid change of D- ala D- ala to D- ala D- lac
Nifedipine - Verapamil - Diltiazem
1. Pioglitazone 2. Rosiglitazone.

23. How are Interferons (INF) used clinically?

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24. What do you treat Nematode/roundworm (pinworm - whipworm) infections with?
Mebendazole/Thiabendazole - Pyrantel Pamoate
Cephalosporins
Increase target cell response to insulin.
reduce levels of Angiotensin II - thereby preventing the inactivation of bradykinin (a potent vasodilator); renin level is increased

25. Adverse effects of Guanethidine?
Ibuprofen - Naproxen - and Indomethacin
It must be Phosphorylated by Viral Thymidine Kinase
orthostatic and exercise hypotension - sexual dysfunction - diarrhea
Rash - Pseudomembranous colitis

26. What is the mechanism of Azathioprine?
Antimetabolite derivative of 6- mercaptopurine that interferes with the metablolism and synthesis of nucleic acid.
1) Hypersensitivity reactions 2) Increased nephrotoxicity of Aminoglycosides 3) Disulfiram - like reaction with ethanol (those with a methylthiotetrazole group - e.g. - cefamandole)
Acetylcholine esterase
Dermatophytes (tinea - ringworm)

27. What is the category and mechanism of action of Zileuton in Asthma treatment?
1) Aminoglycosides = bactericidal 2) Tetracyclines = bacteriostatic
Methylxanthine.
viral kinase
Antileukotriene; blocks synthesis by lipoxygenase.

28. For Warfarin What is the Duration of action
Chronic (weeks or months)
Small lipid - soluble molecule
Ototoxicity - Hypokalemia - Dehydration - Allergy (sulfa) - Nephritis (interstitial) - Gout
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

29. What is a common drug interaction associated with Griseofulvin?
No
- Triggers apoptosis - CLL - Hodgkin's in MOPP - Cushing - like syndrome
Increases coumadin metabolism
proarrhythmic

30. What cholinomimetics might your pt be taking for his glaucoma
impotence - exacerbation of asthma - CV effects - CNS effects - may mask hypoclycemia
Systemic mycoses
Carbachol - pilocarpine - physostigmine - echothiophate
- Steroids - Tamoxifen

31. Which diuretics cause alkalosis?
loop diuretics - thiazides
- S- phase anti - metabolite Pyr analogue - Colon - solid tumors - & BCC/ - Irreversible myelosuppression
- Constant AMOUNT eliminated per unit time. - Etoh & ASA
all of them

32. What enzyme is responsible for the degredation of Ach
first dose orthostatic hypotension - dizziness - headache
1. Phospholipase A2 is prevented from releasing arachidonic acid 2. Decreases protein synthesis thus lowering amount of Cyclooxygenase enzymes
Acetylcholine esterase
1. Suppresses organ rejection after transplantation 2. Selected autoimmune disorders.

33. Name two LPL stimulators.
ACIDazolamide' causes acidosis
decrease
Gemfibrozil - Clofibrate
1) Chloramphenical = bacteriostatic 2) Erythromycin = bacteriostatic 3) Lincomycin = bacteriostatic 4)cLindamycin = bacteriostatic

34. Toxic effects of TMP include?
Erythromycin - Azithromycin - Clarithromycin
Megaloblastic anemia - Leukopenia - Granulocytopenia
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
Anaerobic infections (e.g. - B. fragilis - C. perfringens)

35. Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease - why??
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
With supplemental Folic Acid
Small lipid - soluble molecule
Centrally acting alpha agonist - thus causing a decrease in central adrenergic outflow - spairing renal blood flow

36. What is the formula for Volume of distribution (Vd)
Vd= (Amt. of drug in body/ Plasma drug conc.)
Treatment of infertility.
Short.
Dermatophytes (tinea - ringworm)

37. What antimuscarinic drug is useful for the tx of asthma
Ipratropium
Inhibit RT of HIV and prevent the incorporation of viral genome into the host DNA
1. Meningococcal carrier state 2. Chemoprophylaxis in contacts of children with H. influenzae type B
constipation - flushing - edema - CV effects (CHF - AV block - sinus node depression) - and torsade de pointes (Bepridil)

38. Why are the Sulfonylureas inactive in IDDM (type -1)?
Ciprofloxacin - Norfloxacin - Ofloxacin - Grepafloxacin - Enoxacin - Nalidixic acid
Because they require some residual islet function.
Sulfonamides - Trimethoprim
Paranteral (IV - SC)

39. List the specific antidote for this toxin: Salicylates
- Vitamin K & fresh frozen plasma
- Alkalinize urine & dialysis
- Protamine
torsade de pointes - excessive Beta block

40. Foscarnet toxicity?
- Acetaldehyde - Nausea - vomiting - headache - & hypotension
Nephrotoxicity
1. Taken daily 2. No protection against STDs 3. Raises triglycerides 4. Depression - weight gain - nausea - HTN 5. Hypercoagulable state
viral kinase

41. For Warfarin What is the Route of administration
Mg = Must go to the bathroom.
new arrhythmias - hypotension
- Quinidine - quinine
Oral

42. What process does Zafirlukast interfere with?
Leukotrienes increasing bronchial tone.
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
1. Weight gain 2. Hepatotoxicity (troglitazone)
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine

43. Name three Antiarrhythmic drugs in class IV.
Beta Blockers
Verapamil - Diltiazem - Bepridil
GI distress - Skin rash - and Seizures at high plasma levels
Cephalosporins

44. Which drug(s) cause this reaction: Stevens - Johnson syn. (3)?
CL= (rate of elimination of drug/ Plasma drug conc.)
Wide spectrum of systemic mycoses: Cryptococcus - Blastomyces - Coccidioides - Aspergillus - Histoplasma - Candida - Mucor
increased AP duration - increased ERP increased QT interval. Atrial and ventricular.
- Ethosuxamide - sulfonamides - lamotrigine

45. Which cancer drugs work at the level of mRNA(2)?
- Steroids - Tamoxifen
Aluminum sucrose sulfate polymerizes in the acid environment of the stomach and selectively binds necrotic peptic ulcer tissue. Acts as a barrier to acid - pepsin - and bile.
Norepinephrine (Alpha1 -2 and beta 1)
Botulinum

46. Antiarrhythmic class IV- clinical use?
Systemic mycoses
- Ethosuxamide - sulfonamides - lamotrigine
prevention of nodal arrhythmias (SVT)
Long.

47. What are toxicities associated with Chloramphenicol?
Inhibition of 50S peptidyl transferase - Bacteriostatic
Aplastic anemia (dose independent) - Gray Baby Syndrome
Intrathecally
blocking the beta adrenergic receptor leads to decreased cAMP - and decreased Ca2+ flux

48. What is the major toxic side effect of Penicillin?
Mechanism unknown; possibly inhibits gluconeogenesis and increases glycolysis; effect is to decrease serum glucose levels
No
Hypersensitivity reactions
- Vitamin K & fresh frozen plasma

49. Name three Antiarrhythmic drugs in class IB.
Beta antagonist.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)
Lidocaine - Mexiletine - Tocainide
Interferes with microtubule function - disrupts mitosis - inhibits growth

50. List the mechanism - clinical use - & toxicity of Cyclophosphamide.
- Alkalating agent - NHL - Breast - ovary - & lung. - Myelosuppression - & hemorrhagic cystitis.
- Methotrexate - 5 FU - 6 mercaptopurine
Ipratropium
Carbenicillin - Piperacillin - and Ticarcillin