. I don't feel well suited for this role.
I've been in this problematic situation before and I'm a forensic psychiatrist-the one group you figure would have the background and training to be comfortable with it.
What usuallly ends up happening is the patient is told something to the effect that the only way they're going to get out of whatever incarceration they're in is to take the med, they're usually not given the standard of care of what they're supposed to be told concerning the risks, and then they're released. Then the system dumps the responsibility onto a doctor in the community who in this case (you) likely actually wants to follow the rules and inform the patient of the risks of this medication.
So you're stuck between a rock and a hard place. Take this guy off the meds increasing his risk of resuming his sexually problematic behavior or keep him on it. What if he wants to be taken off of it after you tell him the risks and side effects? Is he supposed to go back to prison or a forensic psych unit? You'll likely not get many answers here. Good luck in trying to talk to the judge. They're hardly ever responsive to clinical doctor's requests. As for anyone else, expect to spend lots of time over the phone that where you can't bill for it.
What I would do is find out what type of arrangement was made that got this person released, and if he has to answer to someone such as a probation officer or judge. Then inform them of the situation (with his permission of course) and work from there. In no way shape or form should you medicate this guy simply because the judge wants you to do it. Medication is supposed to be between the patient and doctor unless the judge has some legal ground to force it--and this may vary per state. Even then the doctor is supposed to be part of the decision making process.
If the patient agrees to take it knowing the risks fine. If they don't you're now caught in a very uncomfortable situation where now I don't know what to tell you because on the one side case-law firmly establishes that a patient needs to be told the risks/benefits and cannot be forced on a med unless court-ordered or is an immediate danger to others. On the other hand this person likely is only in the community because they're on this med, ordered by a judge who has no idea that there's a possibility the person could be taken off of it.
My advice for docs is don't even get into this position to begin with unless you are confident in this area.
Now also mind you that people aren't supposed to smoke while on Depo-Provera. If this guy is smoking it's contraindicated. Now WTF do you do when every single sex offender you see smokes and is given to you already on Depo-Provera and doesn't want to quit?
For yourself, I'd read up on the latest data on chemical castration. AAPL has a few articles on it. Here's an example of one.
http://www.jaapl.org/content/23/1/19.full.pdf+html?sid=473c71c3-2e54-41a2-ac2f-c73c21424023
We should stay away from this IMHO
As was the recommendation given to Supreme Court by several highly respected people in the field, yet the Court in essence responded something to the effect of somebody's got to deal with it, might as well be you....
How do you approach these patients in long term follow up ?
Treat this like it's an antipsychotic in terms of metabolic problems. Depo-Provera at megadoses for sex offenders can cause serious metabolic problems.
Don't be shy on ordering labs for coagulation values as this stuff can cause DVTs. If your patient is smoking (and they likely are...) get them off of smoking.
Consider checking for osteoporosis.
Document that the patient is on this medication voluntarily and that you discussed the risks and benefits with them.
Here's a good article as a start
http://www.jaapl.org/content/37/1/59.full?sid=072eed76-5d14-4536-b9cc-e6185fa8df67