A client presents to the Emergency Department with gastrointestinal bleeding. The family has brought a bag of the client's medications to the hospital. Upon reviewing the client's medications, which could be responsible for the GI bleeding? Select all that apply.

A. Allopurinol: Allopurinol is a xanthine oxidase inhibitor used to lower uric acid levels in conditions like gout. It is not associated with gastrointestinal bleeding, although hypersensitivity reactions and rare liver toxicity can occur. B. Acetaminophen: Acetaminophen primarily affects the liver in overdose situations and does not typically cause gastrointestinal mucosal injury or bleeding at therapeutic doses. It is considered safer than NSAIDs in patients at risk for GI complications. C. Ibuprofen: Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. This decreases protective gastric mucosa, increasing the risk of gastric irritation, ulcers, and gastrointestinal bleeding, especially with chronic use or high doses. D. Meloxicam: Meloxicam is another NSAID with COX-1 and COX-2 inhibition, which similarly reduces mucosal protection in the stomach and increases the risk of GI bleeding. Both ibuprofen and meloxicam are common culprits in NSAID-induced gastrointestinal hemorrhage. E. Sumatriptan: Sumatriptan is a selective serotonin receptor agonist used to treat migraines. It primarily causes vasoconstriction in cranial blood vessels and is not known to cause gastrointestinal bleeding.