I don't mean to be rude but if the script is legitimate and the person pays for it, whether out of pocket or through insurance, what business is it of yours? Your job is to make sure the person's medications don't interact negatively with each other and dispense a medication the way a Doctor has written it while making sure everything is done properly and legally. Would you have the same questions about someone who has bipolar disorder going on and off of their meds?
Honestly, they are most likely switching back and forth between a full-agonist opiate/opioid and Suboxone in order to lower their tolerance and go on binges when they get some extra money or whatever, like everyone else has said. But if Suboxone allows someone with an extremely high tolerance to illegal opiates/opioids and allows them to dry out, spend less money that they don't have, commit less crime (whether it be to fund their habit or just the act of buying heroin/oxycodone/whatever) and maybe get their life into a little better shape than it was before they had access to Suboxone, then I think it's a step in the right direction.
Sometimes Suboxone is also too expensive for a person to maintain on. It's not cheap, not even compared to illegal opiates. So maybe their script says take 4mg in the morning and 4mg at night -- maybe the patient is taking 2mg in the morning and 2mg at night, in order to make that one script last for 2 months. I've found the lower the Suboxone dosage, the better it works, IME. Suboxone is a good short term drug, but like any other opioid with such a long half-life, it's incredibly difficult to get off of it for good. Some people even use it to get high. (Which I don't understand at all.) So there's that as well.
There are so many different reasons though. Do you see this a lot as a pharmacist? What piqued your interest in this issue? You can just ask the patient what's going on if you have a good relationship with them. Like, maybe, "I noticed you forgot to pick up your script last month, would you like me to give you a reminder call?" Now you got me curious, even though it's also none of my business
