RH-34 is a compound which acts as a potent and selective partial agonist for the 5-HT<sub>2A</sub> serotonin receptor subtype. It was derived by structural modification of the selective 5-HT<sub>2A</sub> antagonist ketanserin, with the 4-(p-fluorobenzoyl)piperidine moiety replaced by the N-(2-methoxybenzyl) pharmacophore found in such potent 5-HT<sub>2A</sub> agonists as NBOMe-2C-B and NBOMe-2C-I. This alteration was found to retain 5-HT<sub>2A</sub> affinity and selectivity, but reversed activity from an antagonist to a moderate efficacy partial agonist.
RH-34 is a controlled substance in Hungary and Brazil. It is not a controlled substance in Canada as of 2025. It is also not an explicitly controlled substance in the United States.