Mercadante, S., Ferrera, P., & Casuccio, A. (2010). Effectiveness and tolerability of amidotrizoate for the treatment of constipation resistant to laxatives in advanced cancer patients. Journal of Pain and Symptom Management, 41, 421–425.

To evaluate the effectiveness of amidotrizoate by the percentage of patients unresponsive to their current laxative regimens who had a bowel movement within 24 hours after administration.

All patients with cancer admitted to an acute pain relief and palliative care unit during a one-year period were surveyed. If patients had no bowel movement for three consecutive days despite receiving regular doses of senna, lactulose, or a combination of both, they were consented to participate in the study. Patients were hydrated via IV and then given 50 ml of amidotrizoate orally. A repeat dose could be given the next day, based on clinical judgment or patient preference.

• The study reported on a sample of 99 patients (63 men and 36 women).
• Mean patient age was 65.7 years (SD = 12.2).
• Cancer sites were lung (n = 30), genitourinary (n = 19), gastrointestinal (n = 11), breast (n = 8), pancreas (n = 8), head and neck (n = 6), and other (n = 17).
• Previous treatments were chemotherapy (n = 29), surgery (n = 23),  and radiation (n = 3).

• Single site
• Inpatient
• Italy

The study has clinical applicability for end-of-life and palliative care.

This was a prospective trial.

• Nausea scale (0 to 3)
• Demographic information: age, gender, primary tumor, previous abdominal surgery, chemotherapy, radiotherapy in the last month, and use of opioids in the last month
• Presence of early satiety
• Reduction of fluid and food intake scale (0 to 3)
• Time to first bowel movement
• Adverse effects from amidotrizoate

• Of the evaluable patients, 80.8% were receiving opioids.
• Within 24 hours after amidotrizoate administration, 44.4% of patients had a bowel movement and patients reported significant improvement in nausea, hydration, and nutrition.
• Early satiety symptoms improved in the amidotrizoate group (p < 0.048).
• The effect of amidotrizoate on bowel movement was independent of age, Karnofsky Performance Status, days of constipation, use or dose of opioids, primary tumor, or concomitant chemotherapy or radiotherapy.
• The treatment was more effective in patients who had a history of abdominal surgery.
• The most frequent adverse effect reported was diarrhea in 19 patients.

Amidotrizoate is an effective and well-tolerated alternative therapy for patients with advanced cancer and constipation.

• The sample was small (less than 100).
• There was no blinding, with potential for bias. 
• The study was performed in a specific setting (an acute palliative care unit) where patients may be at end of life; therefore, other patient populations or settings may need to be considered to avoid bias.

Amidotrizoate is used in radiology as a contrast media. Additional research is needed on the use of this agent as a laxative before it can be considered for patients with constipation.