Hi Alex, and welcome on the forum.
There is no treatment that has been shown effective for everyone having POIS, so you will have to do some testing.
You can go see my POIS types chart, which will help you find some safe treatment that has been proven useful for members here. It is a work in progress, and it is not refined enough at this stage to predict what treatment should be the best in a particular case. See the chart at
http://poiscenter.com/forums/index.php?topic=2338.msg19448#msg19448 .
At any rate, it is against forum rules to tell anybody what treatment he should try or what supplement he should take. If you choose to try any of the treatments proposed here, be sure to proceed slowly, one new thing at a time, and safely, using only safe dosage, and consult a health professional before doing so, to be sure that it can be tried considering your health status and the medications you already take.
In the chart, there are more complex methods, but there are also rather simple methods, like the use of some niacin before O, or taking anti-inflammatory ( NSAID) before O, and these can be easier as a starting point, if they fit your health condition.
Let us know if you have questions, and let us know of your results, even if they are not positive.