Hey there
@N9ne
@NoPain91 gave a pretty good summary. I'll throw my hat in the ring to give you multiple viewpoints.
The clinic system is pretty standardized in the US and Canada. I can't speak for Europe and elsewhere. It's likely similar everywhere.
The clinic was designed to treat Heroin addicts. It worked just as well for the Pharma Opioid addicts decades later, as they were fairly similar to Heroin. Fentanyl is highly-variable in its potency compared to even Heroin. It's highly potent and this higher potency makes it more difficult for folks with a gas-station digital scale to make their drugs the proper strength.
I believe also that the shorter-acting nature of Fentanyl has led to a less-organized approach to self-administration. Heroin is taken 3 times per day typically which is easy for us to appropriate into our schedules as our days are often separated by our meals and the time in-between, generally eating three meals a day. When someone needs to take Fentanyl 5 or even 6 times a day to stay well, it's pretty easy to end up taking it 7 or 8 times in a given day. We also know that as far as medical science has shown, Opioid Dependence is practically infinite in how high it can go in a person.
Now the clinics have to deal with people coming in with dependencies several orders greater than they would've seen in previous generations. This makes the induction process difficult. I've talked with a few other people here on BL and in my personal life that have gone from Fentanyl to the clinic. Whereas a Heroin addict will feel the worst of withdrawal taken away by 30mg-40mg, these people are not feeling better until they get to 80mg or so. This is a combination of the higher dosage intersecting with time away from the Fentanyl. Many end up going to 120mg or higher.
If I were you I would prepare for a couple of weeks of discomfort while you have time away from the Fentanyl and are able to get to an effective dosage. The key here is that you need to stop using the Fentanyl. If you go to the clinic and start taking Methadone every day while continuing to take the Fentanyl, you're going to end up in a way worse and way more complex situation.
Most clinics will raise you by 10mg every 5 days, but they can make special dispensations if you're severely ill. When I say "severely ill" I mean really sell it to them. This is the gist. Let us know if you have any questions. You have a lot of proud veterans of the clinic system here.