When comparing stomach-related side effects between aspirin and newer options, it's important to consider the differences in how these medications affect the gastrointestinal (GI) tract.

Aspirin is a nonsteroidal anti-inflammatory drug (NSAID) that can cause GI side effects such as stomach ulcers, bleeding, and perforation [1][2]. These risks are dose-dependent and increase with long-term use or higher dosages [1]. Aspirin-induced GI side effects are primarily due to the drug's ability to inhibit both cyclooxygenase-1 (COX-1) and COX-2 enzymes, which are crucial for maintaining the mucosal lining of the stomach [2].

Newer NSAIDs, such as celecoxib (Celebrex), are selective COX-2 inhibitors [2]. By primarily inhibiting COX-2, these medications reduce inflammation and pain while having a lower risk of GI side effects compared to non-selective NSAIDs like aspirin [2]. However, COX-2 inhibitors are not devoid of GI risks and can still cause ulcers and bleeding, albeit at a lower rate than aspirin [2].

Acetaminophen (Tylenol) is another common pain reliever that is not an NSAID and generally has a lower risk of GI side effects compared to aspirin and other NSAIDs [3]. Acetaminophen works by inhibiting prostaglandin synthesis in the central nervous system, which helps reduce pain and fever [3]. However, long-term use or high dosages of acetaminophen can lead to liver toxicity [3].

In summary, aspirin has a higher risk of stomach-related side effects compared to newer NSAIDs like celecoxib and acetaminophen. However, both newer NSAIDs and acetaminophen still carry some risk of GI side effects and other adverse reactions [1][2][3]. Patients should consult their healthcare providers to determine the most appropriate pain relief option based on their individual needs and medical history.

Sources:
[1] <https://www.drugpatentwatch.com/p/tradename/ASPIRIN>
[2] <https://www.yalemedicine.org/news/acetaminophen-nsaids-over-the-counter-pain-relievers>
[3] <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7347500/>