Does Diamox (Acetazolamide) cause sulfonamide allergies?

From the Guidelines

Diamox (acetazolamide) is unlikely to cause sulfa allergies in patients without a history of sulfonamide antimicrobial adverse reactions, as it is classified as a sulfonamide non-antimicrobial with no or weak evidence of cross-reactivity 1. When considering the use of Diamox in patients with a known sulfa allergy, it is essential to note that the risk of cross-reactivity is minimal due to the structural differences between sulfonamide antimicrobials and nonantimicrobial sulfonamides 1. Key points to consider include:

• Diamox is a carbonic anhydrase inhibitor, which is a class of medications with no or weak evidence of cross-reactivity in patients with a history of sulfonamide antimicrobial adverse reactions 1.
• The presence of an aromatic amine group at the N4 position in sulfonamide antimicrobials is responsible for the differences in cross-reactivity 1.
• Patients with a history of reactions to sulfonamide antibiotics, including the sulfone dapsone, are at minimal risk of cross-reactivity with Diamox 1.
• If a patient with a known sulfa allergy needs to take Diamox, their healthcare provider may recommend a test dose under medical supervision or suggest an alternative medication, depending on the condition being treated 1. It is crucial to disclose all allergies to healthcare providers when discussing medication options to ensure safe and effective treatment.

From the FDA Drug Label

Since acetazolamide is a sulfonamide derivative, cross sensitivity between acetazolamide, sulfonamides and other sulfonamide derivatives is possible

• Cross-sensitivity between acetazolamide (Diamox) and sulfonamides is possible, which may indicate that patients with a sulfa allergy could potentially react to acetazolamide.
• The FDA drug label suggests that hypersensitivity reactions can occur with acetazolamide, including severe reactions such as Stevens-Johnson syndrome and anaphylaxis 2, 2.
• Therefore, it can be inferred that Diamox may cause sulfa allergies in some individuals, particularly those with a known sulfonamide allergy.

From the Research

Diamox and Sulfa Allergies

• Diamox, also known as acetazolamide, is a medication used to treat various conditions, including altitude sickness, glaucoma, and epilepsy.
• There is a common concern that patients with a sulfa allergy may react to acetazolamide, as it is a sulfonamide derivative.
• However, studies have shown that the risk of cross-reactivity between antibiotic sulfonamides and non-antibiotic sulfonamides like acetazolamide is low 3, 4, 5.
• A review of the literature suggests that acetazolamide can be safely used in patients with a history of sulfa allergy, with no significant increase in the risk of allergic reactions 3, 4, 5.
• In fact, several case reports have demonstrated the successful use of acetazolamide in patients with a history of severe allergic reactions to antibiotic sulfonamides 5.
• A systematic review and meta-analysis of acetazolamide side effects found that the risk of common side effects, such as paresthesias and taste disturbances, is dose-dependent, but did not find an increased risk of allergic reactions in patients with a sulfa allergy 6.

Key Findings

• Acetazolamide is a non-antibiotic sulfonamide that is unlikely to cross-react with antibiotic sulfonamides 3, 4, 5.
• Patients with a history of sulfa allergy can be safely treated with acetazolamide, with careful monitoring for potential side effects 4, 5.
• The risk of common side effects, such as paresthesias and taste disturbances, is dose-dependent, and the lowest effective dose of acetazolamide should be used to minimize the risk of side effects 6.