“Split dosing, when used in reference to the medication-assisted treatment of opioid addiction, means instead of once daily dosing, the total medication dose is divided, or split, into two doses.
Methadone and buprenorphine (Suboxone, Zubsolv, etc.) are long-acting opioids.
When we use these medications for opioid addiction, we prefer to dose once per day.
Before I can order split dosing, I need to get permission from the state and federal authorities, just like I would for extra take homes doses for patient emergencies. In my state, methadone peak and trough levels are usually requested before they grant permission for split dosing. We draw the patient’s blood three hours after their dose, which is the peak. That’s the highest blood level the patient will have on that dose. On the next day, right before they take the next day’s dose, we draw another methadone blood level, called the trough, which is the lowest level the patient ever has on that dose.
Then we compare the peak to the trough. If the peak is more than twice the trough level, the patient is probably a fast metabolizer who will feel better taking part of their dose in the morning and part in the evening.”
Source: JanaBurson.com – July 6, 2014