Treatment of Interstitial Cystitis

Why SSRIs Are Not Appropriate

The American Gastroenterological Association recommends against using SSRIs for irritable bowel syndrome, a related visceral pain condition, as they did not significantly improve global symptoms or pain (RR 0.74; 95% CI 0.52-1.06), with the upper confidence interval boundary suggesting possible worsening of symptoms 1, 2.
SSRIs increase gastrointestinal and bladder motility through increased serotonin concentration at nerve endings, which could theoretically exacerbate urinary frequency and urgency—core symptoms of interstitial cystitis 1, 3.
SSRIs have no demonstrated impact on visceral sensation, which is a critical component of bladder pain in interstitial cystitis 4, 5.

TCAs work through multiple mechanisms including inhibition of serotonin and noradrenergic reuptake, blockade of muscarinic receptors (reducing bladder spasm), and effects on pain modulation—all beneficial for interstitial cystitis 4, 5.
TCAs are superior to SSRIs for visceral pain conditions, with demonstrated efficacy for global symptom relief (RR 0.67; 95% CI 0.54-0.82) and pain relief in related conditions 4, 5.

The American Gastroenterological Association guidelines suggest that SSRIs, such as fluoxetine, should not be prescribed for interstitial cystitis due to lack of efficacy data and potential to worsen urinary symptoms through increased bladder motility 1, 3.