Clinical findings:
(1) abdominal pain (occult GI bleeding)
(2) bloody stools (GI bleeding)
(3) dehydration (increased toxicity)
(4) confusion, delirium or mental status change (neurologic toxicity)
(5) dizziness, decreased hearing and/or ringing in the ears (ototoxicity)
(6) unexplained fever
(7) asthmatic or allergic symptoms (allergic reaction)
(8) excessive ethanol use (increased risk of GI bleeding)
Change in medications with drug interactions:
(1) oral anticoagulants (increased bleeding)
(2) oral hypoglycemic agents (hypoglycemia)
Laboratory tests:
(1) urine pH (sudden acidosis can result in increased free plasma drug levels)
(2) fecal occult blood (occult GI bleeding)
(3) iron deficiency anemia (occult GI bleeding)
(4) serum salicylic acid concentrations
