Dentistry and Allergies: Part Three – Sulfa’s and Sulfites

Dentistry and Allergies

Sulfa and Sulfite drugs are quite different from one another, yet they both play a role in dentistry. Allergies to both of them are also reasonably common.

Sulfa (Sulfonamides)

As mentioned above, allergies to Sulfa drugs are pretty standard… 3% of the population have ‘sensitivities’ to them. Because of this, doctors need to be quite cautious when prescribing them.

They were first used to treat bacterial infections in the 1930’s. They are still prescribed as antibiotics in dentistry and other areas and are also found in some medications, I.e., diuretics and anticonvulsants.


People confuse the Sulfa with the Sulfites, yet they are chemically unrelated.

Sulfites are found naturally in most wines. They are also used as a preservative in other types of food. Sulfites are a common food allergen. They rank 9th behind milk, eggs, peanuts, tree nuts, wheat, soy, fish and shellfish.

One percent of people are allergic to Sulfites.

As mentioned in the previous blog, Sulfites (Metabisulfite and Sodium bisulphites) are preservatives which prevent dental local anesthetics from getting brown. The ‘browning’ will decrease the effectiveness of the local anesthetic. Sulfites also act as a preservative by keeping the epinephrine fresh.

In the next blog, we will wrap up our series on common dental allergies. We will look at two types of medication used to deal with infections and pain in dentistry, respectively: Penicillin and Codeine…until then.

You can rest assured that before a dental exam or procedure, our caring dentists in Brampton ensure that you or your family member(s) are not allergic to any of the items mentioned.

Yours in excellent oral hygiene,

Dr. F. Keshavarz Dentistry, DDS

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The image above is that of ‘pericoronitis’….I realize that it’s not the most pleasant image,

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