Divided or Single Exposure (DOSE) Study

Inclusion Criteria:

* Aged 18 years of age or older
* Currently receiving methadone for treatment of OUD for \>90 days and have been consuming the same dose for \>30 days
* Have previously received a take-home dose of methadone as part of routine care
* Willing to comply with study schedule
* Report pain (specific definition blinded)
* Have a cellular phone or be willing to carry phone provided by the study during one phase of the study

Exclusion Criteria:

* Pregnant
* Presence of acute medical problem that requires immediate and intense medical management
* Presence of a serious and unstable mental illness that interferes with provision of voluntary informed consent and/or adherence to study visits
* Plans to leave methadone treatment during the study period
* Maintained on a dose of methadone that would prevent effective splitting of doses
* Currently receiving split doses of methadone
* Currently receiving treatment for pain for which the split-dosing of methadone is judged by medical staff to be contraindicated or otherwise interfere with study conduct or integrity
* Does not meet criteria for mild-severe disability (definition blinded)