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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. What is a possible toxicity of Alpha - glucosidase inhibitors used in type -2 diabetes?
GI disturbances.
No
vascular sm. Mus.: Nifedipine>Diltiazem>Verapamil
Antifungal.

2. Resistance mechanisms for Chloramphenicol
Norepinephrine
Those patients who are taking nitrates.
Inhibits formation of Initiation Complex - causes misreading of mRNA - Bactericidal
Modification via Acetylation

3. List the mechanism - clinical use - & toxicity of Etoposide.
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
CMV - esp in Immunocompromised patients
GI discomfort
- Topo II inhibitor(GII specific) - Oat cell of Lung & prostate - & testicular - Myelosuppression & GI irritation.

4. Antimicrobial prophylaxis for Meningococcal infection
GI side effects. (Indomethacin is less toxic - more commonly used.)
Albuterol - tertbutaline
Same as penicillin. Act as narrow spectrum antibiotics
Rifampin (DOC) - minocycline

5. What is the MOA of Ganciclovir?
Inhibits CMV DNA polymerase
physostigmine
Early myocardial infarction.
Delirium - Tremor - Nephrotoxicity

6. Furosemide increases the excretion of What ion?
Ca2+ (Loops Lose calcium)
narcolepsy - obesity - and attention deficit disorder (I wouldn't recommend this)
depresses ectopic pacemakers - especially in digoxin toxicity
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.)

7. What are two Alpha - glucosidase inhibitors?
1. Acarbose 2. Miglitol
very short acting
physostigmine
ARF - shock - drug overdose - decrease intracranial/intraocular pressure

8. What parasitic condition is treated with Ivermectin?

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9. What is the clinical use for Nystatin?
Topical and Oral - for Oral Candidiasis (Thrush)
Aminoglycosides
Reserpine inhibits dopamine transport into vesicles - attenuating its conversion to NE by dopamine beta - hydroxylase.
GI intolerance (nausea - diarrhea) - Hyperglycemia - Lipid abnormalities - Thrombocytopenia (Indinavir)

10. Which RT inhibitors cause a Rash?
Flecainide - Encainide - Propafenone
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
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.
Non - Nucleosides

11. Adenosine - clinical use?
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
DOC in diagnosing and abolishing AV nodal arrhythmias
- Deferoxamine
Overdose produces hepatic necrosis; acetaminophen metablolite depletes glutathione and forms toxic tissue adducts in liver.

12. Resistance mechanisms for Macrolides

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13. What is Niclosamide used for?
Sildenafil fills the penis
They activate the ciliary muscle of the eye (open angle) and pupillary sphincter (narrow angle).
Cestode/tapeworm (e.g. - D. latum - Taenia species Except Cysticercosis
Oral

14. Digoxin v. Digitoxin: bioavailability?
Digitoxin>95% Digoxin 75%
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
Digitoxin 168hrs Digoxin 40 hrs
carbonic anhydrase inhibitors - K+ sparing diuretics

15. What is the MOA for Nystatin?
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
Botulinum
Binds ergosterol - Disrupts fungal membranes
Because they require some residual islet function.

16. What conditions are treated with Metronidazole?
reversible SLE- like syndrome
Heparin catalyzes the activation of antithrombin III.
Giardiasis - Amoebic dysentery (E. histolytica) - Bacterial vaginitis (Gardnerella vaginalis) - Trichomonas
very short acting

17. What is the mechanism of action of Misoprostol?
Digitoxin>95% Digoxin 75%
Misoprostol is a PGE1 analog that increases the production and secretion of the gastic mucous barrier.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
- Sulfonamides - INH - ASA - Ibuprofen - primaquine - nitrofurantoin /- pyrimethamine - chloramphenicol

18. Why would a patient with cog - wheel rigidity and a shuffling gait be given benztropine?
Methylxanthine.
Parkinson patients benefit from antimuscarinic agents through its inhibitory action within the indirect pathway.
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Digitoxin 168hrs Digoxin 40 hrs

19. How can Isoniazid (INH)- induced neurotoxicity be prevented?
Tetracycline - Doxycycline - Demeclocycline - Minocycline
Chloramphenicol - Erythromycin/macrolides - Lincomycin - Clindamycin - Streptogramins (quinupristin - dalfopristin)
Small lipid - soluble molecule
Pyridoxine (B6) administration

20. Will Hemicholinum affect the release of stored Ach during Cholinergic Stimulation
No - hemicholinum block the uptake of Choline and thus Ach synthesis
anticholinesterase glaucoma
Systemic mycoses
Buy AT 30 - CELL at 50'

21. How is Vancomycin used clinically?
For serious - Gram + multidrug - resistant organisms
Acute coronary syndrome; coronary stenting. Decreases the incidence or recurrence of thrombotic stroke.
Lipoxygenase
Beta1 more than B2

22. What enzyme does Zileuton inhibit?
Impairs the synthesis of vitamin K- dependent clotting factors
Lipoxygenase
Norepinephrine
Disulfiram - like reaction with EtOH - Headache

23. Are not penicillinase resistant
1. Renal damage 2. Aplastic anemia 3. GI distress
Hemolytic anemia
Giant Roundworm (Ascaris) - Hookworm (Necator/Ancylostoma) - Pinworm (Enterobius)
Carbenicillin - Piperacillin - and Ticarcillin

24. Acetaminophen has What two clinical uses and lacks What one clinical use of the NSAIDs?
- Chloramphenicol - benzene - NSAIDS - PTU - phenytoin
1. Antipyretic 2. Analgesic 3. Anti - inflammatory 4. Antiplatelet drug.
Acetaminophen has antipyretic and analgesic properties - but lacks anti - inflammatory properties.
Because they require some residual islet function.

25. What is used to reverse the action of Heparin?
anuria - CHF
Topical and Oral - for Oral Candidiasis (Thrush)
Protamine Sulfate is used for rapid reversal of heparinization (positively charged molecule that binds to negatively charged heparin).
- Class III antiarrhythmics (sotalol) - class IA (quinidine)

26. What is Ketoconazole specifically used for?
Norepinephrine
Nephrotoxicity (esp. with Cephalosporins) - Ototoxicity (esp. with Loop Diuretics)
G6PD deficient individuals
Blastomyces - Coccidioides - Histoplasma - C. albicans; Hypercortisolism

27. Acetazolamide - clinical uses?
Cardiac glycoside (inotropic agent).
glaucoma - urinary alkalinization - metabolic alkalosis - altitude sickness
Paranteral (IV - SC)
dry mouth - sedation - severe rebound hypertension

28. What is the clinical use for Heparin?
Immediate anticoagulation for PE - stroke - angina - MI - DVT.
Methylxanthine.
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.
GI discomfort

29. What are two indirect acting adrenergic agonists?
amphetamine and ephedrine
Misoprostol is contraindicated in women of childbearing potential because it is an abortifacient.
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
TMP- SMZ

30. What are four Sulfonylureas?
Aminoglycosides
Post - op and neurogenic ileus and urinary retention - myasthenia gravis - and reversal of neuromuscular junction blockade (post - op) through anticholinesterase activity.
cardiac muscle: Verapamil>Diltiazem>Nifedipine
1. Tolbutamide 2. Chlorpropamide 3. Glyburide 4. Glipizide

31. Adverse effects of Reserpine?
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
sedation - depression - nasal stuffiness - diarrhea
TMP- SMZ (DOC) - aerosolized pentamidine
ACIDazolamide' causes acidosis

32. What is the category of drug names ending in - cycline (e.g. Tetracycline)
Methylation of rRNA near Erythromycin's ribosome binding site
- EDTA - dimercaprol - succimer - & penicillamine
Pentamidine
Antibiotic - protein synthesis inhibitor.

33. Aztreonam is not ________ with penicillins
ACE inhibitor.
Dermatophytes (tinea - ringworm)
1)Binds penicillin - binding proteins 2) Blocks transpeptidase cross - linking of cell wall 3) Activates autolytic enzymes
cross - allergenic

34. Which drug(s) cause this reaction: Adrenocortical Insufficiency
AV nodal cells
- Glucocorticoid withdrawal
Interferes with microtubule function - disrupts mitosis - inhibits growth
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.

35. Which drug(s) cause this reaction: P450 induction(6)?
- Barbiturates - phenytoin - carbamazipine - rifampin - griseofulvin - quinidine
CMV Retinitis in IC pts When Ganciclovir fails
Depolymerizes microtubules - impairing leukocyte chemotaxis and degranulation.
anuria - CHF

36. What is the mechanism of action of Acetaminophen?
Headache - flushing - dyspepsia - blue - green color vision.
- Corticosteroids - heparin
Reversibly inhibits cyclooxygenase - mostly in CNS. Inactivated peripherally.
BM suppression (neutropenia - anemia) - Peripheral neuropathy

37. What are common side effects of Amphotericin B?
Fever/Chills - Hypotension - Nephrotoxicity - Arrhythmias
Because they require some residual islet function.
Pituitary hormone.
Inhibits bacterial Dihydrofolate Reductase - Bacteriostatic

38. Name three K+ sparing diuretics?
1. Renal damage 2. Aplastic anemia 3. GI distress
Anaerobic infections (e.g. - B. fragilis - C. perfringens)
Spironolactone - Triamterene - Amiloride (the K+ STAys)
TCA

39. What drug is used to treat Trematode/fluke (e.g. - Schistosomes - Paragonimus - Clonorchis) or Cysticercosis
Praziquantel
Staphlococcus aureus
- DNA intercalator - Hodgkin's - myeloma - sarcoma - and solid tumors - Cardiotoxicity & alopecia
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

40. What is the clinical use for Clomiphene?
Beta - lactamase cleavage of Beta - lactam ring
Inhibits xanthine oxidase - decresing conversion of xanthine to uric acid.
Treatment of infertility.
Decreases synthesis of Mycolic Acid

41. Antiarrhythmic class II- effects?
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.)
decrease the slope of phase 4 - increase PR interval (the AV node is particularly sensitive)
Methylation of rRNA near Erythromycin's ribosome binding site
- MT polymerization inhibitor(M phase) - MOPP - lymphoma - Willm's & choriocarcinoma - neurotoxicity and myelosuppression

42. Describe Phase II metabolism in liver(3)?
block Na+ channels in the cortical collecting tubule
- acetylation - glucuron. - & sulfation - Conjugation - Polar product
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
Scopolamine

43. Acetaldehyde is metabolized by Acetaldehyde dehydrogenase - Which drug inhibs this enzyme?
Competitive inibitor of progestins at progesterone receptors.
Verapamil - Diltiazem - Bepridil
dizziness - flushing - constipation (verapamil) - nausea
- Disulfram & also sulfonylureas - metronidazole

44. Resistance mechanisms for Sulfonamides
Inhibit viral DNA polymerase
Digitoxin 70% Digoxin 20-40%
1) Serious Gram - infections resistant to other Beta lactams 2) Meningitis (most penetrate the BBB)
Altered bacterial Dihydropteroate Synthetase - Decreased uptake - or Increased PABA synthesis

45. Describe first - order kinetics?
Bind cell membrane - disrupt osmotic properties - Are Cationc - Basic and act as detergents
Constant FRACTION eliminated per unit time.(exponential)
sedation - positive Coombs' test
Tricyclic antidepressant.

46. List the specific antidote for this toxin: Opioids
- B51Naloxone / naltrexone (Narcan)
- MT polymerization stabilizer - Ovarian & breast CA - Myelosupperession & hypersensitivity.
To inhibit renal Dihydropeptidase I and decrease Imipenem inactivation in the renal tubules
Flutamide is a nonsteroidal competitive inhibitor of androgens at the testosterone receptor - used in prostate carcinoma.

47. Sotalol - toxicity?
torsade de pointes - excessive Beta block
- Disulfram & also sulfonylureas - metronidazole
DHPG (dihydroxy-2- propoxymethyl guanine)
Stimulating beta receptors stimulates heart rate - but beta receptor induced vasodilation reduces peripheral resistance.

48. How is Trimethoprim used clinically?
Used in combination therapy with SMZ to sequentially block folate synthesis
- Alkalating agents+cisplatin - Doxorubicin+Dactinomycin - Bleomycin - Etoposide
pulmonary edema - dehydration
Dermatophytes (tinea - ringworm)

49. What antimicrobial class is Aztreonam syngergestic with?
In treatment of malignant hyperthermia - due to concomitant use of halothane and succinylcholine. Also in neuroleptic malignant syndrome - a toxicity of antipsychotic drugs.
- Alkalate DNA - Brain tumors - CNS toxicity
CMV - esp in Immunocompromised patients
Aminoglycosides

50. Adverse effects of Methyldopa?

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