Sulfonamides

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What are sulfonamides?

Sulfonamides (sulfa drugs) are drugs that are derived from sulfanilamide, a sulfur-containing chemical. Most sulfonamides are antibiotics, but some are prescribed for treating ulcerative colitis. Sulfonamide antibiotics work by disrupting the production of dihydrofolic acid, a form of folic acid that bacteria and human cells use for producing proteins.

What are examples of sulfonamides available in the US?

Examples of sulfonamides include:

Many of these drugs are available only in generic forms.

What are the side effects of sulfonamides?

Sulfonamides may cause dizziness, headache, lethargy, diarrhea, anorexia, nausea, vomiting, and serious skin rashes. Sulfonamides should be stopped at the first appearance of a skin rash before the rash becomes severe.

Serious rashes include:

Sulfonamides also may cause sensitivity to the sun that leads to extensive sunburn after exposure to sunlight (photosensitivity). Patients receiving sulfonamides should avoid excessive exposure to sunlight and should wear sunscreen.

Other rare side effects include liver damage, low white blood cell count (leucopenia), low platelet count (thrombocytopenia), and anemia. Formation of urinary crystals which may damage the kidney and may cause blood in the urine. Adequate hydration is needed to prevent the formation of urinary crystals.

What drugs interact with sulfonamides?



Sulfonamides can increase the blood-thinning effects of warfarin (Coumadin), possibly leading to abnormal bleeding.

Medically Reviewed by a Doctor on 3/3/2014



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