The effects of high fat diet consumption on morphine-induced constipation.

Opioids, prescribed for pain relief or as maintenance therapies for opioid use disorder, induce constipation, which can lead to medication compliance issues. However, it is not known how dietary manipulation might impact opioid-induced constipation. To test the hypothesis that eating a high fat diet exacerbates opioid-induced constipation, male and female Sprague-Dawley rats ( n  = 8/diet/sex) were fed either a low fat (standard) diet, a high fat/high carbohydrate diet, or a ketogenic diet. Rats were injected with either saline or morphine (1-10 mg/kg) and constipation was measured by counting fecal boli hourly for 6 h. Morphine-induced comparable constipation in all groups; however, rats eating a high fat/high carbohydrate or ketogenic diet produced significantly less feces following injections of saline or morphine as compared to rats eating a standard diet ( P  < 0.05). Dietary considerations might be important for patients prescribed opioid medications.