Type, severity, and localisation of non-steroidal anti-inflammatory drug (NSAID) toxicity
| Side effects | Onset and development | |
| Mild side effects | ||
| • Dyspepsia | Within hours, often regressive despite maintenance of treatment | |
| • Gastrointestinal erosions (stomach > duodenal bulb) | ||
| Moderate side effects | ||
| • Iron-deficiency anaemia | ||
| • Gastrointestinal ulcers (stomach and intestine) | Rare <6 weeks | |
| • Scarring (antrum and duodenal bulb) | ||
| Serious complications | ||
| • Severe gastrointestinal bleeding (stomach >duodenal bulb >oesophagus, small, and large intestine) | Rare <6 weeks of treatment. Progressive increase in a near linear fashion during long term treatment | |
| • Acute perforation (duodenal bulb >colon) | ||
| • Gastric outlet obstruction | ||
The predominant localisations are listed in parentheses.