By Jyothirmai Gubili, MS, Eugenie Spiguel, MSN, ANP-BC, and Yen Nien (Jason) Hou, PharmD, Dipl OM, LAc

Diarrhea is a distressing condition that significantly affects patients’ quality of life and social functioning. Characterized by passage of more than three unformed stools in 24 hours, in cancer it can be caused by chemotherapy, radiotherapy, laxatives and antibiotics, enteral feeding, malabsorption syndromes, colectomy, or several types of malignant tumors. Diarrhea has also been reported in long-term cancer survivors. Standard treatment options such as opiate agonists and adsorbents are associated with side effects that may increase a patient’s symptom burden.

What the Research Reveals

Shen Ling Bai Zhu San (SLZBS) is a traditional Chinese medicine (TCM) formula composed of 10 herbs used as a remedy for chronic diarrhea. Current clinical evidence of efficacy of SLZBS is based on studies conducted largely in Asian populations; it is the second most prescribed formula for patients in Taiwan after colon cancer surgeries.

In a four-arm randomized controlled trial, 80 patients diagnosed with diarrhea predominant–irritable bowel syndrome (D-IBS) were randomized to receive SLZBS (5 g, three times daily) plus otilonium bromide, an antispasmodic agent (40 mg, three times daily); SLZBS plus placebo; otilonium bromide plus placebo; or two placebos. After eight weeks, researchers found significant improvements in abdominal discomfort (p = 0.005) in the SLZBS + otilonium bromide and SLZBS + placebo arms compared to the latter two groups. After 12 weeks, patients also reported significant differences in abdominal pain (p = 0.030) and pain frequency (p = 0.005). Although the differences in stool frequency were statistically insignificant, improvements in stool consistency based on the Bristol stool form chart scale were significant (p = 0.003). Differences in adverse reactions, including abdominal pain and fever, were statistically insignificant (p > 0.05).

Researchers also reported positive findings from a systematic review and a meta-analysis that included 14 trials of 1,158 patients with D-IBS, ulcerative colitis, and those with idiopathic diarrhea. Compared to conventional medicine, SLZBS was associated with greater patient-reported satisfaction (p < 0.00001); SLZBS combined with conventional medicine also increased patient-reported satisfaction compared with conventional medicine alone (p = 0.0004), and the formula was not associated with a greater risk of adverse events such as constipation, nausea, vomiting, or abdominal distention compared with conventional medicine or placebo (p = 0.009).

Overall, current data suggest that SLZBS is safe and beneficial, but most of the clinical studies were limited by small sample sizes, moderate risk of bias in reporting outcomes, and varied dosing regimens. Methodologically robust trials are needed to strengthen the evidence.

SLZBS’s mechanisms of action are not fully known. Findings from pharmacologic studies indicate that its components promote intestinal barrier integrity, modulate gut microbiota by decreasing potential pathogens and increasing beneficial bacteria, and regulate inflammatory factors.

Reported side effects include constipation, nausea, vomiting, abdominal distention, rash, and allergy.

What Oncology Nurses Need to Know

The TCM formula SLZBS has a long history of use in Asia. Clinical studies have documented improvements in stool consistency, frequency, and abdominal pain in patients with IBS and ulcerative colitis. When compared to conventional antidiarrheal medication, SLZBS was associated with fewer side effects and greater patient satisfaction. Clinical trials have yet to be conducted in cancer populations, and the ONS Guidelines™ have not evaluated SLZBS or other TCM for chemotherapy-induced diarrhea.

For patients who seek nonpharmacologic options, oncology nurses should refer them to licensed TCM practitioners experienced in working with patients with cancer.