What type of drug is Oxandrolone that was found in the system of  Cinthya Domínguez in 2015?
Oxandrolone Oxandrolone (brand names Oxandrin, Anavar, Lonavar, others), is a synthetic, orally active anabolic-androgenic steroid (AAS) that first became available as a prescription drug in the United States in 1964. It is a 17α-methylated derivative of dihydrotestosterone (DHT) that has an oxygen atom in place of the carbon at the 2 position.
Difelikefalin Difelikefalin (INN) (developmental code names CR845, FE-202845), also known as -Phe--Phe--Leu--Lys-[γ-(4-N-piperidinyl)amino carboxylic acid] (as the acetate salt), is an analgesic opioid peptide acting as a peripherally specific, highly selective agonist of the κ-opioid receptor (KOR). It is under development by Cara Therapeutics as an intravenous agent for the treatment of postoperative pain. An oral formulation has also been developed. Due to its peripheral selectivity, difelikefalin lacks the central side effects like sedation, dysphoria, and hallucinations of previous KOR-acting analgesics such as pentazocine and phenazocine. In addition to use as an analgesic, difelikefalin is also being investigated for the treatment of pruritus (itching). Difelikefalin has completed phase II clinical trials for postoperative pain and has demonstrated significant and "robust" clinical efficacy, along with being safe and well-tolerated. It is also in phase II clinical trials for uremic pruritus in hemodialysis patients.