Colonoscopy A flexible tube with a camera on the end (colonoscope) is introduced into the rectum and advanced through the colon during a colonoscopy
doi: 10.1562/2006-01-30-RA-787 11
Uncommon and rare adverse effects include cystitis, folliculitis, gastrointestinal infections, hypersensitivity reactions, changes in appetite, depression, insomnia, balance disorders, lethargy, restless leg syndrome, syncope, photophobia, presbyopia, tinnitus, confusion, palpitations, hypertension, hypercholesterolaemia, and weight gain
Porphyrin pigment normally occurs in tissues only in small amounts and is a precursor of the heme portion of hemoglobin (Churukian 2002)
The authors note that this risk was particularly evident among patients also using antidepressants