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37 Cards in this Set

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Questions: What is true about ciproflxacin is accurate?
Tendinitis and tendon rupture may occur during treatment.
Questions: Supplementary folinic acid may prevent anemia in folate-deficient persons who use this drug, a weak base that achieves tissue levels similar to those in plasma?
Trimethoprim, which is a weak base.

Fluoroquinolones and sulfonamides are acidic compounds and its high lipid solubility at blood pH allows for penetration into prostatic and vaginal fluid.
Questions: What statement about sulfonamides is accurate?
Sulfonamides inhibit dihydropteroate synthase. Example of applying this concept: Dysfunction of the basal ganglia may occur in the newborn if sulfonamides are administered late in pregnancy.

It is a bacteriostatic drug.
Questions: The combination of trimethoprim and sulfamethoxazole is effective against which opportunistic infection in the AIDS PT?
Toxoplasmosis (it is effective against some protozoans)
Questions: A 24 year old woman has returned from a vacation abroad suffering from traveler's diarrhea, and her problem has not responded to antidiarrheal drugs. A pathogenic gram-negative bacillus is suspected. Which drug is most likely to be effective in the treatment of this PT?
Levofloxacin (fluoroquinolones are very effective in diarrhea caused by bacterial pathogens).
Questions: What statement about the clinical use of sulfonamides is true?
Resistant bacterial strains may have decreased intracellular accumulation of sulfonamides; sulfonamides have activity against C. trachomatis and can be used topically for the treatment of chlamydia infections of the eye; sulfonamide resistance can occur in some strains of bacteria because of increased production of PABA.
Questions: A 31 year old man has gonorrhea. He has no drug allergies, but a few years ago acute hemolysis followed use of an antimalarial drug. The physician is concerned that the PT has an accompnaying urethritis caused by C trachomatis, although no cultures or enzyme tests have been performed. Which of the following drugs is most likely to be effective against both gonococci and C. trachomatis in this PT?
Ofloxacin and other fluoroquinolones (however, norfloxacin is the least active fluoroquinolone) are effective against both. Cefixime is effective only against gonorrhea.
Questions: What statement about the fluoroquinolones is accuate?
Antacids decrease oral bioavailability of fluoroquinolones. Neither hepatic nor renal dysfunction is contraindicated with the use of fluoroquinolones (most undergo renal elimination and dosage should be modified with creatinine clearance <50 mL/min). Fluoroquinolones should not be used first with children due to effects on cartilage. Gonococcal resistance to fluorquinolones may involve changes in DNA gyrase.
Questions: A 55 year old man complains of periodic bouts of diarrhea with lower abdominal cramping and intermittent rectal bleeding. Seen in the clinic, he appears well nourished, with blood pressure in the normal range. Examination reveals moderate abdominal pain and tenderness. His current medications are limited to loperamide for his diarrhea. Signmoidoscopy reveals mucosal edema, friability, and some pus. Laboratory findings include mild anemia and decreased serum albumin. Microbiologic examination via stool cultures and mucosal biopsies do not reveal any evidence for bacterial, amebic, or cytomegalovirus involvement. A preliminary diagnosis is made of mild to moderate ulcerative colitis. The most appropriate drug to use in this PT is?
Sulfasalazine. Without evidence to microbial cause of colitis, a drug that reduces inflammation is indicated. Sulfasalazine is also used for its anti-inflammatory effects in rheumatoid arthritis.
Questions: What statement about the combination of trimethoprim plus sulfamethoxazole (TMP-SMX) is true?
It is an alternative to ampicillin in the treatment of listeriosis; effective for treatment of pneumonia caused by Pneumocystis jiroveci (not community-acquired pneumonia); fever and pancytopenia occur frequently when these drugs are given to AIDS PTs; produces sequential blockade of folic acid synthesis.
Questions: What adverse effect is most likely to occur with sulfonamides?
Most common is skin rash from hypersensitivity. CNS and hematuria occur less frequently. Kernicterus is rate is Sulfonamides are avoided in the third trimester.
Questions: What drug is effective in the treatment of nocardiosis and, in combination with pyrimethamine, is prophylactic against Pneumoncystis jiroveci infections in AIDS PTs?
Sulfadiazine and TMP-SMX are the DOC for nocardiosis.
Sulfonamides and trimethoprim interfere with?
Folic acid synthesis.
Fluoroquinolones inhibit what?
Microbial nucleic acid metabolism.
Sulfamethoxazole is a structural analog of what, and what is the significance of this?
PABA (para-aminobenzoic acid), a dihydrofolic acid precursor. High levels of PABA analogue competitively inhibits dihydropteroate synthase, the enzyme needed for folic acid synthesis.

Human cells do not make TH4 (tetrahydrofolate). TH4 gives up carbons to form purines and other metabolic building blocks.
Sulfamethoxazole, is it bacteriostatic or bactericidial?
Bacteriostatic
Trimethoprim is a selective inhibitor of?
Bacterial dihydrofolate reductase, thereby, inhibiting folic acid synthesis.
Trimethoprim-sulfamethoxazole (TMP-SMX) is effective against?
Gram negative and Gram positive, Chlamydia trachomatis, Nocardia

TMP-SMX
T: respiratory Tree (Streptococcus pneumoniae and Haemophilus influenzae); otitis media, sinusitis, bronchitis, and pneumonia

M: Mouth (GI tract) for gram-negative for diarrhea (Shigella, Salmonella, Enterobacter, Kelbsiella, E. coli)

P: Pee (genitourinary tract) for UTI, prostatitis, urethritis caused by Enterics (E. coli)

SMX (Syndrome): AIDS, for prophylactic intervention of Pneumonocystis carinii pneumonia.

protozoans (Toxoplasma gondii and Isospora belli)
TMP-SMX is the DOC for?
Nocardia and Pneumocystis jiroveci pneumonia.

Shigella, Salmonella, UTIs
What are the side effects of TMP-SMX?
Steven-johnson syndrome, hemolytic anemia, kernicterus in newborns, bone marrow suppression.

Note: administer folic acid to compensate for megaloblastic anemia, leukopenia, and granulocytopenia.

Allergic reactions
Ciprofloxacin, belongs to what class of drugs?
Fluoroquinolones.
What are the fluoroquinolones and what is the single quinolone? MOA?
-floxacin (e.g., ciprofloxacin, norfloxacin, ofloxacin, sparfloxacin, moxifloxacin, gatifloxacin, enoxacin; nalidixic acid is the quinolone (is rapidly excreted and hardly used.

Inhibits bacterial DNA topoisomerase II (DNA gyrase), inducing DNA strand breakage and cell death in gram negative organisms.
DNA gyrase (topoisomerase II) performs?

What does topoisomerase IV perform?
Induces negative supercoiling of dsDNA that balances the positive supercoiling of DNA replication, acting as a "swivel" to prevent damage to DNA strand.

Bacterial topisomerase initiating decatenation, the mechanism by which 2 daughter DNA molecules are separated at the conclusion of DNA replication.
Fluorquinolones, are they bacteriostatic or bactericidal?
Bactericidal
Fluoroquinolones are effective against?
Gram negatives very well!!--given with abdominal surgery? Widely used for respiratory tract, skin, and soft tissue infections.

Diarrhea via enteric organisms--except anaerobes!!

UTI

Chronic bone infections (osteomyelitis) (Pseudomonas, S. aureus, or Enterobacteriaceae).

Faculatative intracellular organisms (Legionella, Brucella, Salmonella, and atypical Mycobacteria).
What are the SE of fluoroquinolones?
Ciprofloxacin: Tendonitis, and tendon rupture in adults (avoid in children and in pregnancy)

Other fluoroquinolones: same as ciprofloxacin, but also QTc prolongation--caution in class IA and III antiarrhytmics.
Fluoroquinolones are contraindicated in?
Pregnant woman and children due to damage to growing cartilage.
Fluoroquinolone achieves high levels in the?
Stool, kidneys, penetrate well into bone and prostate. AND, achieve high intracellular levels.

Excreted in the bile and reabsorbed in the intestine and then excreted via the kidney.
Trimethoprim, looks like what, and what is the significance of this?
Dihydrofolate reductase. Once TH4 gives up a carbon, it becomes TH2 (dihydrofolate) and must be reduced back to TH4 by dihydrofolate reductase.
TMP-SMX is excreted in what, and what is the significance of this?
In the urine; therefore, it is good for UTIs.
Combination of trimethoprim plus sulfamethoxazole, is bactericidal or bacteriostatic?
Bactericidal.
What is triple sulfa used for?
Due to solubility limitation, a combination of 3 separate sulfonamides are used to reduce the likelihood that any one drug will precipitate.
How are sulfonamides classified?
Sulfisoxazole: short acting

Sulfamethoxazole: intermediate

Sulfadoxine: long-acting
Sulfonamides are active against?
Chlamydia and Nocardia.

UTI: triple sulfa, sulfisoxazole

Ocular infections: topical sulfacetamide

Burn: topical mafenide, silver sulfadiazine

Ulcerative colitis, rheumatoid arthrits: oral sulfasalazine

Toxoplasmosis: oral sulfadizine plus pyrimethamine plus folinic acid.
Specific examples of fluoroquinolone usage: norfloxacin and ofloxacin; levoflxacin, gatifloxacin, and moxifloxacin
Norfloxacin and ofloxacin: mainly for UTIs

Levofloxacin and moxifloxacin: are "respiratory" fluoroquinolones with enhanced activity against gram-positive cocci and atypicals (chlamydia, legionella, mycoplasma).
Gemifloxacin and moxifloxcin usage?
Have the widest spectrum: includes both gam-positive and gram negative, and some anaerobic bacteria and atypical pneumonia agents.
Sulfa drug allergies?
Sulfasalazine, sulfonylureas, thiazide diuretics, acetazolamide, or furosemide.