💊

Sulfonamides Overview and Nursing Care

Sep 18, 2025

Overview

This lecture covers sulfonamides (sulfa drugs), their key characteristics, uses, side effects, and important nursing considerations.

Sulfonamides Overview

  • Sulfonamides are antibiotics commonly called sulfa drugs.
  • Drugs that start with "sulfa", like sulfamethoxazole and sulfadiazine, are sulfonamides.
  • Sulfonamides are different from sulfonylureas, which are diabetic medications.

Mechanism of Action

  • Sulfonamides kill bacteria but are not effective against viruses or fungi.
  • They work by blocking the synthesis of folic acid required for bacterial growth.

Clinical Uses

  • Used to treat a wide variety of bacterial infections.

Adverse Effects & Precautions

  • Sulfa allergies are common and may cause allergic reactions; monitor patients closely, especially on first exposure.
  • Cross-sensitivity may occur with other sulfa-derived drugs, such as sulfonylureas and thiazide diuretics.
  • Can cause crystalluria (urine crystals), which may lead to kidney stones and damage.
  • May cause photosensitivity, increasing risk of sunburn.
  • Can lead to folate deficiency by inhibiting folic acid synthesis.
  • Sulfonamides are teratogenic (harmful to fetus) and should be avoided in pregnancy.

Nursing Considerations

  • Advise patients to stay well-hydrated (at least 2 liters/day) to prevent crystalluria.
  • Counsel patients to use sunblock, wear protective clothing, and avoid direct sunlight.
  • Patients may need folic acid supplementation.
  • Ensure pregnant women do not take sulfonamides.

Key Terms & Definitions

  • Sulfonamides — Antibiotics that start with "sulfa" and kill bacteria by blocking folic acid synthesis.
  • Crystalluria — Presence of crystals in urine, can cause kidney damage.
  • Photosensitivity — Increased sensitivity to sunlight, leading to higher risk of sunburn.
  • Teratogenic — Causes developmental defects in a fetus.

Action Items / Next Steps

  • Review names and indications for common sulfonamides.
  • Memorize key side effects, especially allergy, crystalluria, and teratogenicity.
  • Practice patient education points on hydration, sun safety, and folic acid for exams.