Is it safe to take aspirin (acetylsalicylic acid) when allergic to Naprosyn (naproxen)?

From the Guidelines

If you are allergic to naprosyn (naproxen), you can generally take aspirin safely as they are different types of medications, though both belong to the non-steroidal anti-inflammatory drug (NSAID) class. However, there is a possibility of cross-reactivity between different NSAIDs in some individuals. If you have had a severe allergic reaction to naprosyn, it would be prudent to consult with your healthcare provider before taking aspirin. The most recent study 1 provides a classification of NSAIDs based on their chemical structure, which can help guide the decision to take aspirin. According to this study, aspirin is a salicylate, while naprosyn is a propionic acid, suggesting that they are distinct and may not cross-react in all individuals. Typical aspirin dosing for pain or fever is 325-650 mg every 4-6 hours as needed, not exceeding 4,000 mg per day. For anti-inflammatory purposes, higher doses may be prescribed. If you experience any signs of an allergic reaction after taking aspirin, such as hives, swelling, wheezing, or difficulty breathing, seek immediate medical attention. Another study 1 suggests that single NSAID-induced urticaria, angioedema, or anaphylaxis may occur, but the underlying etiology is not fully understood. The study also notes that direct challenges to aspirin in patients with a remote history of an aspirin reaction and recent tolerance of a separate NSAID are nearly always negative. A third study 1 provides guidance on the management of single NSAID reactors and suggests that a diagnostic aspirin challenge or aspirin desensitization may be considered. However, the study also notes that individual patients may exhibit some criteria from each column, and the clinician will need to determine based on an aggregate assessment of these factors whether to offer a challenge or consider aspirin desensitization. In general, it is recommended to consult with a healthcare provider before taking aspirin if you have a history of allergic reactions to naprosyn or other NSAIDs. The healthcare provider can assess the individual's risk of cross-reactivity and determine the best course of action. Some key points to consider include:

• Aspirin and naprosyn are different types of NSAIDs with distinct chemical structures
• Cross-reactivity between NSAIDs is possible, but not guaranteed
• A diagnostic aspirin challenge or aspirin desensitization may be considered in some cases
• Individual patients may require different approaches based on their medical history and risk factors
• Consultation with a healthcare provider is recommended before taking aspirin if you have a history of allergic reactions to naprosyn or other NSAIDs.

From the FDA Drug Label

Naproxen tablets are contraindicated in the following patients: Known hypersensitivity (e.g., anaphylactic reactions and serious skin reactions) to naproxen or any components of the drug product [ see WARNINGS AND PRECAUTIONS (5.7,5.9)] History of asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs. Severe, sometimes fatal, anaphylactic reactions to NSAIDs have been reported in such patients [ see WARNINGS AND PRECAUTIONS (5.7,5.8)]

Aspirin and Naprosyn Allergy

• If a patient is allergic to Naprosyn, it is likely they will also react to aspirin due to the risk of cross-reactivity between NSAIDs.
• The label warns of severe, sometimes fatal, anaphylactic reactions in patients with a history of allergic-type reactions to aspirin or other NSAIDs 2. It is not recommended to take aspirin when allergic to Naprosyn due to the potential risk of an anaphylactic reaction.

From the Research

Allergic Reactions to Naprosyn and Aspirin

• Patients allergic to naprosyn may experience cross-reactive reactions to other nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin 3, 4.
• The mechanism of cross-reactivity is thought to be related to the inhibition of cyclooxygenase-1 (COX-1) isoenzyme, which is shared among NSAIDs 5.
• Desensitization to aspirin may result in cross-desensitization to other NSAIDs that inhibit COX-1 5.

Concomitant Use of Aspirin and NSAIDs

• The concomitant use of low-dose aspirin and NSAIDs may interfere with the antiplatelet effect of aspirin, although the clinical significance of this interaction is still unclear 6.
• The interaction between aspirin and NSAIDs varies among agents and is dependent on factors such as dose timing, dose of aspirin, and dose of the NSAID 6.

Cross-Reactivity between Aspirin and Naprosyn

• There is evidence of cross-reactivity between aspirin and naprosyn, as well as other NSAIDs, in patients with fixed drug eruption 4.
• The challenge test is considered the "gold standard" for establishing or excluding a diagnosis of NSAID hypersensitivity, including cross-reactivity between aspirin and naprosyn 3.