Alyssa Phillips, Hannah Burnett and Jennie Brannigan were tested at the Ocala-Reddick Concours Complet International in Florida in the United States last November.

Samples taken from the athletes all returned positive for amphetamine.

In addition, Phillips' sample contained canrenone and the sample taken from Brannigan also included methylphenidate and ritalinic acid.

All three athletes were provisionally suspended from December 21, 2017, the date of notification of their adverse analytical findings under the FEI Anti-Doping Rules for Human Athletes.

Under the terms of the settlements, a one-year period of ineligibility will be imposed on the trio from the date of sample collection, November 18, 2017.

The athletes will each pay a fine of CHF 1,500 (£1,100/$1,500/€1,300) and their results from the competition will be disqualified.

Each of the parties will bear their own legal costs.

Additionally, the athletes are required to support the FEI in its anti-doping campaign and to actively engage in athlete education, including providing testimonials for FEI education material.

The athletes must also complete an anti-doping education course within one year of the FEI Tribunal's final decision.

"All three athletes were able to prove no significant fault or negligence and the circumstances of the cases show that none of them had the intention to dope," FEI legal director Mikael Rentsch said.

"In light of this, and the fact that the athletes have subsequently been granted Therapeutic Use Exemptions (TUEs) for these medications, the parties agreed that the period of ineligibility should be reduced to 12 months, and the FEI Tribunal has approved that."

In accordance with the World Anti-Doping Agency (WADA) Code, the FEI has notified WADA and the United States Anti-Doping Agency of the FEI Tribunal decisions.

"It is with the upmost passion and commitment that I will be returning to the competitive world of eventing," Burnett was reported as saying in a statement by The Chronicle of the Horse.

"I have taken full responsibility for my actions and am grateful for the opportunity to return to the sport I so deeply love.

"Abiding by the rules that have been placed to ensure fair competition within the sport of eventing is important to me.

"While I am taking a doctor-prescribed medication, I acknowledge and regret that I began taking the medication before submitting a Therapeutic Use Exemption.

"I have since gone through the FEI process and been granted a TUE going forward.

"I am humbled by the support and forgiveness of those closest to me despite my mistakes.

"To everyone who fought for me and believed in me when I couldn’t do so for myself - from the bottom of my heart, thank you.

"I know it will take time to re-build the trust of many of my fans and supporters, but I am committed to doing exactly that."

Brannigan added: "I’m incredibly happy to know that I will be able to come back to compete again this November, and while this situation has been tough on my sponsors, students, owners and support team I am truly thankful that I have learned how to love the sport even from the sidelines.

"I am grateful to everyone who has stood by me and I am extremely sorry to have let our sport, country and my supporters down.

"That being said, I am appreciative to the FEI for recognising I wasn’t taking the medication to try to improve my performance and that indeed I will be allowed to compete on this medication going forward.

"I know I have learned a lot from this experience and I hope it has helped others be more educated on anti-doping as well."