What is the prevalence of nimesulide (Nonsteroidal Anti-Inflammatory Drug (NSAID)) allergy?

Prevalence of Nimesulide Allergy

Nimesulide allergy is relatively uncommon, with hypersensitivity reactions occurring in approximately 2-8% of patients with known NSAID hypersensitivity, making it generally well-tolerated as an alternative NSAID in most patients with histories of reactions to other NSAIDs.

Epidemiology of Nimesulide Allergy

Nimesulide is a selective COX-2 inhibitor with a different chemical structure from traditional NSAIDs, which contributes to its generally favorable tolerability profile in patients with NSAID hypersensitivity. The prevalence of allergic reactions to nimesulide varies depending on patient characteristics:

• In the general population with NSAID hypersensitivity, only about 2.1% of patients experienced urticaria during treatment with nimesulide after previously tolerating a challenge test 1
• Among patients with known aspirin/NSAID intolerance, approximately 8.3% demonstrated hypersensitivity reactions to nimesulide during oral challenge tests 2
• In patients with a history of NSAID-induced skin disorders, nimesulide intolerance was observed in about 10-19% of cases, particularly in those with specific risk factors 3

Risk Factors for Nimesulide Hypersensitivity

Several factors increase the risk of nimesulide hypersensitivity:

• History of chronic urticaria - significant risk factor for cross-reactivity 1, 3
• Atopic status - atopic individuals have a higher risk (23% vs 9%) of reactivity to nimesulide (RR = 3.2) 3
• History of antibiotic hypersensitivity - increases risk of nimesulide reactions 1
• Multiple NSAID hypersensitivities - patients with reactions to multiple classes of NSAIDs are at higher risk 1
• History of anaphylactoid reactions to NSAIDs - represents a significant risk factor (RR = 5.7) 3
• Aspirin intolerance - increases risk for nimesulide-induced urticaria (RR = 5.4) 3

Clinical Manifestations of Nimesulide Hypersensitivity

When nimesulide hypersensitivity does occur, it typically presents as:

• Urticaria/angioedema (most common presentation) 2, 3
• Mild respiratory symptoms (rhinitis, dyspnea) 2
• Rarely, more severe reactions in high-risk patients

Management Considerations

For patients requiring NSAIDs with a history of hypersensitivity:

• Nimesulide can be considered as an alternative in patients with hypersensitivity to other NSAIDs, particularly those with respiratory reactions 2
• Prior tolerance testing is recommended, especially in patients with identified risk factors 1
• Challenge protocol typically involves gradual dose escalation (starting with 10-25mg and increasing to the therapeutic dose of 100mg) 1, 2
• For patients with multiple risk factors, alternative analgesics such as selective COX-2 inhibitors or non-NSAID options should be considered 4

Comparison to Other NSAIDs

Nimesulide's selective COX-2 inhibition profile contributes to its generally better tolerability compared to traditional NSAIDs:

• Traditional NSAIDs cause hypersensitivity reactions in up to 9% of the general population and up to 30% of asthmatic patients 5
• Nimesulide is generally well-tolerated by NSAID-intolerant patients and patients with NSAID-induced asthma 5
• Nimesulide has shown a potentially lower incidence of gastrointestinal adverse effects compared to other NSAIDs 6

Practical Recommendations

When considering nimesulide in patients with potential NSAID hypersensitivity:

1. Assess for risk factors (chronic urticaria, atopy, multiple NSAID reactions, history of anaphylaxis)
2. Consider oral challenge testing in a controlled setting before routine use in high-risk patients
3. Start with lower doses and gradually increase to therapeutic doses
4. Monitor for cutaneous and respiratory symptoms, particularly in the first hours after administration
5. Have alternative analgesic options available for patients who demonstrate nimesulide hypersensitivity

In summary, while nimesulide is generally well-tolerated in patients with hypersensitivity to other NSAIDs, certain risk factors increase the likelihood of cross-reactivity, and appropriate precautions should be taken in these high-risk populations.