2,5-Dimethoxy-4-iodoamphetamine (4-iodo-2,5-dimethoxyphenylisopropylamine or DOI), a psychedelic drug and hallucinogen has high affinity and is a potent agonist for each of the 5-HT2 receptor subtypes: 5-HT2A, 5-HT2B, and 5-HT2C. DOI's effects have been compared to LSD. DOI has a stereo center and R-(−)-DOI is the more active stereoisomer. It was shown, that R-(−)-DOI via 5-HT2A receptor could inhibit a variety of TNF-alpha-mediated proinflammatory markers, including intracellular adhesion molecule 1 (ICAM-1), vascular adhesion molecule 1 (VCAM-1), and interleukin (IL)-6 gene expression. It is known, that TNF-alpha-mediated inflammatory pathways have been strongly implicated in a number of diseases, including atherosclerosis, rheumatoid arthritis, psoriasis, type II diabetes, depression, schizophrenia, and Alzheimer's disease. Thus, because (R)-DOI can significantly inhibit the effects of TNF-alpha many hours after the administration of TNF-alpha, potential therapies could be aimed not only at preventing inflammation but at also treating the inflammatory injury that has already occurred or is ongoing.

Ritalinic acid is an inactive, major metabolite of methylphenidate, a schedule II drug in the United States commonly used as a psychostimulant drugs methylphenidate and ethylphenidate. The elimination half-life of methylphenidate is relatively short (approximately 2 hours); therefore it is also available in extended release (ER) forms. The main metabolite is ritalinic acid, and the methylphenidate metabolites are mostly excreted in urine.