- Jennifer Middleton, MD, MPH
An estimated 4 million adults in the United States have interstitial cystitis (IC), a syndrome that can cause a variety of bothersome and uncomfortable urinary tract symptoms. The January 15 issue of AFP reviews the evidence base for treating IC; although researchers have yet to identify an effective long-term pharmacologic treatment, two short-term medication options exist with different effects on symptom scores.
This AFP FPIN Clinical Inquiry examined a systematic review from 2007 as well as a couple of more recent randomized controlled trials. The systematic review found heterogenity in study design and outcomes among included randomized controlled trials (RCTs), and the mean duration of these RCTs was only 15 weeks. The FPIN authors note that, in 6 studies, pentosan improved overall symptom scores ("better or worse than prior the intervention") but did not improve scores for specific symptoms like dysuria, urgency, or frequency.
Although the systematic review authors included a small 2001 RCT investigating cimetidine in their tables, they did not comment on it in their manuscript; the FPIN authors, however, had more interest in this study that randomized 36 participants to treatment with cimetidine versus placebo. Although the n is quite small, this RCT did show improvement in overall symptom scores as well as in the specific symptoms of nocturia and suprapubic pain.
Family physicians seeking to help their patients with IC may want to base their medication choice on each patient's symptoms. Although pentosan has been best studied for overall symptoms, cimetidine may be a useful alternative for patients whose predominant symptoms are nocturia and/or suprapubic pain.
Although the American Urological Association (AUA) recommends the use of amitriptyline for IC, the FPIN authors found conflicting evidence. While a smaller RCT (n = 50) showed benefit, a larger RCT (n = 271) did not. The AUA, however, lists all pharmacologic options for IC as second-line treatments, advising patient education, "self-care practices," "behavioral modification," and "stress management practices" as first-line treatments.
In line with those recommendations is a recent study that found a high rate of co-morbid mood symptoms in patients with IC. This 2015 study looked at the association between IC and symptoms of depression, anxiety, and/or insomnia; correlation does not necessarily equal causation, of course, and it's unclear if these symptoms co-exist with IC, predate IC, or come as a result of the frustrating symptoms of IC. Regardless, the hazard ratios (HR) for co-morbid depression, anxiety, or insomnia were 2.4, 2.4, and 2.1, respectively (all HRs had narrow 95th percentile confidence intervals). Although no studies to date have looked at mood treatments for IC, perhaps these studies are not far off given this association. In the meantime, family physicians can at least screen for and treat these co-morbid mood disorders.
If you'd like to read more, there's an AFP By Topic on Urinary Tract Infections/Dysuria that includes this 2011 AFP article on diagnosing and treating IC.
How do you care for patients with IC?