The prevalence of constipation and its relation to sweet taste preference among patients receiving methadone maintenance treatment

•Constipation was highly prevalent among MMT patients.•Constipation is associated with poor sleep and lower quality of life.•Constipation intensity was inversely correlated with duration in MMT.•Constipation is associated with preference for sweets. Preference for sweet-tasting foods, weight gain, and constipation characterize patients receiving methadone maintenance treatment (MMT). The prevalence of constipation in MMT and its relation to preference for sweet taste and body mass index (BMI) are undetermined. A random sample of 83 patients was interviewed for constipation with the Patient Assessment Constipation Quality of Life (PAC-QOL) questionnaire. They rated taste intensity and reward of sweet, salty, and sour solutions by means of a nine-point Likert scale. Data on their BMI, drugs in urine, methadone dose, and serum levels were analyzed. Forty-two patients reported minimum to severe constipation. They characterized as having longer durations of opioid usage before MMT and worse sleep quality than non-constipated patients (logistic regression). Constipation intensity was inversely correlated with duration in MMT and linearly correlated with the Patient Assessment Constipation Quality of Life score. Patients with constipation rated reward to sweet taste significantly higher with no differences in taste intensity compared to non-constipated patients. Patients with high methadone serum levels (≥750 ng/mL) rated taste intensity significantly lower compared to those with normal methadone serum levels (