Chapter 88 - Sulfonamides and Trimethoprim

Which is more toxic? Aminoglycosides or Sulfonamides?

Aminoglycosides

How are sulfonamides and trimethoprims bacteriostatic?

Sulfonamides and Trimethoprims suppress bacterial growth by inhibiting tetrahydrofolic acid, a derivative of folic acid.

What are some adverse effects of sulfonamides?

-Hypersensitivity reactions (Stevens-Johnson Syndrome) -Hematologic effects -Kernicterus**** -Renal damage****

What is Bactrim DS?

A combination of trimethoprim and sulfamethoxazole

Are sulfonamides and trimethoprims bactericidal or bacteriostatic?

Bacteriostatic

What is silver sulfadiazine used for?

Silver sulfadiazine is used to suppres bacterial colonizaion in patients with second- and third-degree burns.

Are sulfonamides and trimethoprims broad-spectrum or narrow-spectrum antibiotics?

Sulfonamides and Trimethoprim are broad-spectrum antibiotics

What is kernicterus (an adverse effect of sulfonamides)?

Sulfonamides can cause thick bile, which doesn't clear. Patient appears jaundice. This happens in pediatrics and OB (can affect the baby).

A patient is receiving local applications of mafenide [Sulfamylon] to burn areas. Before application, it is most important for the nurse to do what? A) Administer a pain medication. Correct B) Obtain a set of vital signs. C) Auscultate the lung fields. D) Obtain a signed consent form.

The answer is A, The sulfonamide mafenide [Sulfamylon] is used to suppress bacterial colonization in patients with burns. Local application frequently is painful. It is important to administer a pain medication before applying mafenide [Sulfamylon]. Obtaining vital signs and a signed informed consent form and auscultating lung fields are not essential actions for mafenide application.

A patient taking a sulfonamide is breast-feeding an infant. Which complication in the infant would the nurse associate with kernicterus? A) Hemolytic anemia B) Neurologic deficits C) Hepatocellular failure D) Ophthalmic infection

The answer is B, Kernicterus is a disorder in newborns caused by deposition of bilirubin in the brain, which leads to severe neurologic deficits and death. Sulfonamides promote kernicterus by displacing protein-bound bilirubin from the proteins, leaving newly freed bilirubin access to brain sites. Sulfonamides are not administered to infants under 2 years old, nor are they given to pregnant patients near term or nursing mothers. Hemolytic anemia, hepatocellular failure, and ophthalmic infection are not associated sulfonamide effects in infants.

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.

The answer is B, 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. Silver sulfadiazine is also relatively painless when applied to the burn.

When caring for a patient receiving mafenide [Sulfamylon] for treatment of a severe burn, it is most important for the nurse to monitor which laboratory value? A) Blood glucose level B) Acid-base status C) Sodium level D) Peak mafenide level

The answer is B, Mafenide [Sulfamylon] therapy is associated with the development of acidosis. Peak mafenide levels are not obtained. The blood glucose and sodium levels are not affected by mafenide.

The nurse is assessing a patient who is receiving a sulfonamide for treatment of a urinary tract infection. To monitor the patient for the most severe response to sulfonamide therapy, the nurse will assess for what? A) Diarrhea B) Skin rash and lesions C) Hypertension D) Bleeding

The answer is B, The nurse's priority is to monitor for hypersensitivity reactions. The most serious response to sulfonamide therapy is Stevens-Johnson syndrome, which manifests as symptoms of the skin and mucous membranes, lesions, fever, and malaise. In rare cases, hematologic effects occur, requiring periodic blood studies.

Before administering trimethoprim, it is most important for the nurse to assess the patient for a history of what? A) Heart failure B) Alcoholism C) Diabetes D) Emphysema

The answer is B, Trimethoprim inhibits bacterial synthesis of folic acid. It is avoided in patients when folate deficiency is likely, such as in alcoholism, because bone marrow suppression may occur. Heart failure, diabetes, and emphysema are unrelated to adverse effects with trimethoprim.

When providing patient teaching for oral sulfonamide therapy, the nurse should instruct the patient to take the sulfonamide in what way? A) At mealtime, when food is available B) With soy or nonmilk products C) Between meals with a full cup of water D) On awakening before breakfast

The answer is C, Oral sulfonamides should be taken on an empty stomach and with a full glass of water. To minimize the risk of renal damage, adults should maintain a daily urine output of 1200 mL. Sulfonamides should not be taken with soy or nonmilk products or food or before breakfast without liquids.

A patient who has acquired immunodeficiency syndrome (AIDS) is receiving trimethoprim/sulfamethoxazole [Bactrim] fore treatment of pneumonia. Which response should a nurse expect if the medication is achieving the desired effect? A) Increase in CD4 T cells B) Increased appetite and weight gain C) Resolution of pneumonia D) Decrease in joint pain

The answer is C, Trimethoprim/sulfamethoxazole is the treatment of choice for Pneumocystis pneumonia (PCP), an infection caused by Pneumocystis jiroveci (formerly thought to be Pneumocystis carinii). PCP is an opportunistic pneumonia caused by a fungus that thrives in immunocompromised hosts. It does not increase the number of CD4 T cells, the targeted cells of the human immunodeficiency virus (HIV), nor does it affect joint pain. Increased appetite and weight gain are not therapeutic actions of trimethoprim/sulfamethoxazole.

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."

The answer is C. Patients taking sulfadiazine should be advised to avoid prolonged exposure to sunlight, wear protective clothing, and apply a sunscreen to exposed skin. Sulfonamides can cause kernicterus in newborns. These drugs should not be administered to pregnant women near term, nursing mothers, or infants under 2 months old. Sulfadiazine causes deposition of sulfonamide crystals, which can injure the kidney. To minimize crystalluria, hydration should be sufficient to produce a daily urine flow of 1200 mL in adults; alkalinization of urine (for example, with sodium bicarbonate) can also help. Patients taking sulfadiazine should drink 8 to 10 glasses of water per day. Sulfonamides can intensify the effects of warfarin, phenytoin, and sulfonylurea-type oral hypoglycemics (for example, glipizide). When combined with sulfonamides, these drugs may require a reduction in dosage. TMP/SMZ is contraindicated for nursing mothers, pregnant women in the first semester or near term, infants under 2 months old, patients with folate deficiency (manifested as megaloblastic anemia), and patients with a history of hypersensitivity to sulfonamides and chemically related drugs, including thiazide diuretics, loop diuretics, and sulfonylurea-type oral hypoglycemics. Instruct patients to complete the prescribed course of treatment, even though symptoms may abate before the full course is over.

A nurse should recognize that which sulfonamide, applied topically, has the greatest therapeutic benefit for burns? A) Sulfadiazine B) Trimethoprim [Primsol] C) Sulfacetamide [Bleph-10] D) Silver sulfadiazine [Silvadene]

The answer is D, Silver sulfadiazine is a topical anti-infective agent used to treat and prevent infection in second- and third-degree burns. Its effects are due primarily to the release of free silver and not to the sulfonamide portion of the molecule. Sulfadiazine and trimethoprim are sulfonamides used systemically, not topically. Sulfacetamide is used for superficial infections of the eye.

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

The answer is D, 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.

The nurse identifies which statements about Stevens-Johnson syndrome as true? (Select all that apply.) A) Patients with Stevens-Johnson syndrome have a mortality rate of about 25%. B) Toxemia is associated with Stevens-Johnson syndrome. C) Short-acting sulfonamides do not induce Stevens-Johnson syndrome. D) Patients with Stevens-Johnson syndrome usually are hypothermic. E) Lesions of the mucous membranes are a characteristic of Stevens-Johnson syndrome.

The answers are A, B, and E. Short-acting sulfonamides do induce Stevens-Johnson syndrome on rare occasions, and patients with Stevens-Johnson syndrome usually are hyperthermic. The other three statements are true.

Which manifestations does the nurse associate with the development of hemolytic anemia? (Select all that apply.) A) Urticaria B) Fever Correct C) Pallor Correct D) Jaundice Correct E) Diarrhea

The answers are B, C, and D. Urticaria and diarrhea are not associated with the development of hemolytic anemia. Fever, pallor, and jaundice are associated with the development of hemolytic anemia.

How do we prevent renal damage from crystalluria in patients taking sulfonamides?

The must drink lOTS of water

If a patient is going to be on a sulfa, what do we have to make sure is functioning in the patient?

Their immune system must be intact because sulfas are bacteriostatic!!

What is the primary use of a sulfonamide?

acute Urinary Tract Infection