Chapter 88 - sulfonamides

what are the therapeutic uses of Trimethoprim/Sulfamethoxazole

-UTI -otitis media -bronchitis -shigellosis -pneumonia -gi infections

what are the averse effects of Trimethoprim/Sulfamethoxazole

-gi effects -rash -hypersensitivity -hyperkalemia -hyperphotosensitivity

what are some bacteria that have formed a resistance are resistant to sulfonamides?

-gonocci, meningococci, streptococci

what are the adverse effects of trimethoprim

-hematologic effects -hyperkalemia -use in pregnancy and lactation

what are the adverse effects of sulfonamides?

-hypersensitivity -hematologic effects -kernicterus - thick biles -renal damage from crystalluria

what do sulfonamides do?

-inhibit synthesis of folic acids but not unilication of folic acids

what are drug interactions with sulfonamides?

-metabolism-related interaction -cross hypersensitivity

how are silver sulfadiazines and mafenides absorbed?

systemically

what are silver sulfadiazines and mafenides used for?

-suppress bacterial colonization in patients with second and third degree burns

A patient who sustained second- and third-degree burns has been prescribed mafenide. Which statement about mafenide does the nurse identify as true? A. Use of mafenide can cause alkalosis. B. Mafenide is painful upon application. C. A blue-green to gray discoloration of the skin occurs with mafenide therapy. D. Mafenide exerts its therapeutic effect by the release of free silver.

Answer: B Rationale: Local application of mafenide is frequently painful. Mafenide is metabolized to a compound that can suppress renal excretion of acid, thereby causing acidosis. Silver sulfadiazine, another topical sulfonamide used for burn therapy, can cause a blue-green to gray skin discoloration, so facial application should be avoided. Mafenide does not cause this specific skin discoloration. Mafenide acts by the same mechanism as other sulfonamides. In contrast, the antibacterial effects of silver sulfadiazine are due primarily to the release of free silver, not to the sulfonamide portion of the molecule.

A patient who takes warfarin has been prescribed sulfadiazine. When teaching the patient about this drug, which statement will the nurse include? A. "If you become pregnant, it is safe to take sulfadiazine." B. "You should limit your fluid intake while taking sulfadiazine." C. "Avoid prolonged exposure to sunlight, wear protective clothing, and apply a sunscreen to exposed skin." D. "You will most likely need to have an increase in the dose of warfarin while taking sulfadiazine."

Answer: C

should you take Trimethoprim/Sulfamethoxazole with or without food?

with

A patient who was taking sulfonamides develops Stevens-Johnson syndrome. Upon assessment, the nurse expects to find what? A. Hypotension B. Bronchospasm C. Temperature of 35.5º C D. Widespread skin lesions

Answer: D Rationale: The most severe hypersensitivity response to sulfonamides is Stevens-Johnson syndrome, a rare reaction with a mortality rate of about 25%. Symptoms include widespread lesions of the skin and mucous membranes, combined with fever, malaise, and toxemia. Bronchospasm and hypotension, as well as tachycardia, are manifestations of anaphylactic reactions.

what is the primary use of sulfonamides?

UTI's

what are the uses or trimethoprim?

acute and uncomplicated UTI

what kind of antibiotics are sulfonamides and Trimethoprim?

broad-sprectrium antibiotics

what do trimethoprim do?

inhibit dihydrofolare reducase, therby blocking reduction of dihydrofolate to tetrahydrofolate and interruptoing DNA synthesis

What does trimethoprim do?

inhibit dihydrofolate reductase , thus suppressing bacterial synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and proteins

why would you use Trimethoprim/Sulfamethoxazole as a combination

it is way more powerful

what are sulfonamides related to?

p-aminobenzoic acids (PABA)

what should you watch when taking the combination Trimethoprim/Sulfamethoxazole ?

plasma drug levels

are silver sulfadiazines and mafenides cidal or static

static

how do sulfonamides and Trimethoprim work?

suppress bacterial growth by inhibiting tetrahydrofolic acid

what are sulfonamides?

synthetic chemotherapeutic antimicobial agents