Isn’t chemical castration worth trying if it works?

Thanks to Corrections Sentencing, I see that folks in Oregon are talking about making greater use of chemical castration for certain high-risk sex offenders.  Here are highlights from this AP story:

The state is close to approving a Corrections Department budget that includes money to expand the state’s chemical castration program.  If passed, the state would pay for high-risk sex offenders to receive twice-monthly shots of Depo-Provera, a testosterone-reducing drug.

Oregon has had a chemical castration law since 1999.  But use of the drug has been spotty because of a lack of a money and opposition from doctors and counselors. Sen. Kurt Schrader, D-Canby, the chief sponsor of the 1999 bill, is leading the effort to add $150,000 to the program, saying it’s been effective when used.

Schrader said he wants the injections to be required as a condition of post-prison supervision for about 20 offenders per month – up from the current five per month – in a pilot program that would include Multnomah County and two other counties that have not been determined.  “Since it has been pretty darn successful, we want to see if there’s a larger population we can use it on to keep people safe when these guys get out of jail,” he said….

Depo-Provera, originally developed as a contraceptive for women, creates sexual apathy in men by reducing the level of testosterone.  European countries have used the drug since the 1960s to treat sex offenders.  It’s less popular in the U.S., and Oregon is one of fewer than 10 states reported to have chemical castration laws.

The AP article is does not report on any research that chemical castration is as effective as Senator Schrader asserts.  But, if there is decent evidence that this form of technocorrections is effective on some high-risk offender populations, I like the idea a lot more than over-broad civil commitment and residency restriction regimes.

Can anyone report (ideally with cites/links) on any research about the efficacy of chemical castration?  If it works, is there any reason not to consider expanding its use for certain high-risk offender populations?