Gastrointestinal safety of NSAIDs and over-the-counter analgesics?It is well recognised that they may adversely cause damage throughout the gastrointestinal tract and aggravate pre-existing disease.Their side effects on the upper gastrointestinal tract can be assessed by various means; each study type has different clinical connotations.Short-term use (less than 14 days) demonstrates dose-dependent damage of prescribed NSAIDs; the damage is proportional to the acidity of the drugs and not seen with Cyclooxygenase-2 (COX-2) selective inhibitors that have a pKa over 7.0.I Bjarnason?