UFC women’s bantamweight contender Mayra Bueno Silva’s biggest career win is in jeopardy of getting overturned, and you can bet she’s not happy about it.

Bueno Silva revealed on Monday that she was informed of a failed drug test in the week leading up to her July fight against former champion Holly Holm, which she won by second-round submission at UFC on ESPN 49. Bueno Silva (11-2-1 MMA, 6-2-1 UFC) said she tested positive for Ritalinic acid, which stemmed from Concerta, her medication for ADHD.

“I have ADHD, and I’ve been taking medication for a long time,” Bueno Silva told MMA Junkie. “I drink Concerta (Methylphenidate), the same (as) Ritalin. I always take this medication, and I stop taking it the Monday of fight week, but this time was different. I take the medication until Monday, but I don’t know what happened. My body don’t metabolize this medication this time.

“I proved that I don’t drink in competition. I proved this because in my test it’s .00000007, and I proved that I don’t drink nothing, but I don’t know what’s happened. I know the commission rule is .00000007. I know, but I think it’s a big mistake with me because I don’t drink nothing.”

Bueno Silva said she’s been taking Concerta for about two to three years and has never had an issue with drug testing in any of her previous UFC fights. She began taking Concerta after a battle with depression.

“I take this medication because my mind is very hyperactive,” Bueno Silva said. “If I don’t take this medication, I won’t hear. I won’t stop (moving). It’s not good for training or fighting. It’s nothing. It doesn’t improve my performance.”

The Brazilian fighter also revealed that she has a prescription for the medication in both the U.S. and Brazil, and that she’s disclosed her use with the UFC, the U.S. Anti-Doping Agency, and the state commissions where she’s fought.

Ahead of the fight against Holm, Bueno Silva said she applied for a therapeutic use exemption with USADA but was requested to provide more documentation after the fight.

Bueno Silva has a hearing with the Nevada Athletic Commission on Thursday. Regardless of the result, Bueno Silva hopes there’s a chance in the rule set, declassifying methylphenidate as a prohibited substance.

“I think they need (to) change this thing because it’s very important for the people that have ADHD,” Bueno Silva said. “I think this thing needs (to) change. If (I am an) example for this, OK, no problem, but I need this changed.

“If you have any problem with mental health, please look for help because this is very, very hard. If this thing needs (to) change and I am (the) model, that’s OK. No problem.”