Space Having Dimmed Effects on Drugs?

So i read an article today about space and drugs (the legal kind) which you can read here.

Anyhow, So after reading this (being one of the very few articles that ever interest me) I thought about blogging about. so i did and here it is. So if you're to lazy to follow the link and read it, i'll sum it up for you. Basically what went down was that A research team (didn't say where it was from, so i'm going to assume it was from the Johnson Space Center) sent four boxes of drugs containing 35 different medications up to the ISS (International Space Station). They also kept four identical boxes of the same drugs at the Johnson Space Center. Then at periodic times, people on the ISS sent them back. One stayed only 13 days, another stayed for 28 months. That's 2 years! well. technically 2 years and 4 months, but whose counting? Anyway the peeps doing the research found that the drugs had a varying decrease in effectiveness. Most by the end didn't pass the potency requirement given by the US's Pharmaceutic group. But there is one upside to this. the drugs that are prone to oxidation, like adrenaline, vitamin c and vitamin a, would do well in the carbon dioxide rich environment. which i believe i failed to mention why the drugs were even degrading in the first place. So there are multiple reasons why these drugs are degrading as they are, varying from radiation to microgravity to changes in humidity and temperature. I hope you enjoyed this! if not then shenanigians.

~W