Note that this this is NOT a protocol. Rather this is part of the design of a double blind study.
I am not familiar with it. But thank you and I looked it up.
It is amazing how large the literature is. Years ago, a supervisor told me more than 15,000 books on psychology alone are published each year.
The signaling systems of the mind-body are highly intertwined with interesting overlaps and additive and oppositional effects, the sum of which determines function.
Part of how opiates work is to increase dopamine signaling, which is a reward signal, giving us a sense of well-being.
Opiates, however, also suppress LH production (thus Testosterone), and adrenal cortex function (reducing Cortisol, Progesterone, DHEA, etc.).
The idea behind using Naltrexone is to block opiates made by the body.
Brennermann, et al, in 1993 did a double-blind study using 50 mg Naltrexone on men with erectile dysfunction. There was an increase in morning erections, but no increase in libido, sexual activity, LH, FSH, or testosterone found.
Sathe, et al, in 2001 give sexually active, healthy men 25 mg of Naltrexone in a double-blind crossover design. This resulted an increase in number of orgasms and intensity of arousal and orgasms while masturbating to porn videos.
Billington, CJ in 1990 gave impotent secondary hypogonadal men Nalmefene, another opioid blocker, via IV. There was a "significant" rise in LH, FSH, testosterone, Cortisol (AM and PM).
Of course, Naltrexone also blocks opiate pain medications like Vicodin, and will throw someone into opiate withdrawal. Thus, for people on chronic pain management, Naltrexone may not be a great idea.
The studies are very interesting.
Reducing dopamine by blocking opiates may lead to an increase in norepinephrine and thus arousal. Fortunately, this is also accompanied by an increase in Cortisol - and adrenal cortex function, since norepinephrine is also the signal for stress, anxiety, irritability. Also fortunately, there is an increase in testosterone, which can increase dopamine to compensate at least partially for the loss.
A question is adverse effects in long-term use. Knocking out one's endogenous opioids poses a problem. For example, the "runner's high" would be knocked out. What about the possible increase in pain-related problems (e.g. joint and muscle pain, headaches)? The possible increase in norepinephrine can cause insomnia, anxiety. A lot of people with sexual dysfunction already have high norepinephrine signaling as a contributing factor to loss of libido. The increase may not be welcomed. The loss of dopamine signaling can cause depression. Etc.
I haven't found Naltrexone that useful for alcohol dependence nor opioid dependence since the psychosocial factors are so large. For alcohol dependence, the patients simply drank more to compensate for the loss of pleasure from alcohol use. Opioid dependent patients usually use treatment to have a break from opiate use, reducing tolerance, which would then allow the use of a lower dose of opiate when they relapse - thus allowing the addiction to be cheaper, a restart. The main problem is forgetting to use a lower dose and using the old dose. The old dose may kill them at the lower tolerance level.
Again, however, the studies are interesting. So thanks.
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