Robalzotan (, ; developmental code names NAD-299, AZD-7371) is a selective antagonist at the serotonin 5-HT<sub>1A</sub> receptor which was under development for the treatment of major depressive disorder, anxiety disorders, gastrointestinal disorders, irritable bowel syndrome (IBS), and overactive bladder.
It was shown to completely reverse the autoreceptor-mediated inhibition of serotonin release induced by the administration of selective serotonin reuptake inhibitors (SSRIs) like citalopram in rodent studies.
The drug was investigated by AstraZeneca as a potential antidepressant, but like many other serotonin 5-HT<sub>1A</sub> receptor modulators, was discontinued. Later on, it was also researched for other indications, such as IBS, but was dropped once again due to lack of effectiveness as well as a poor tolerability profile, which included effects such as "hallucinations or hallucination-like adverse events".