Abstract: A gastroretentive, sustained-release dosage form including 5-hydroxytryptophan (5-HTP) as an active ingredient and low-dose carbidopa is described. For example, the dosage form can be provided as a bilayer tablet comprising a swelling layer and a modified release layer, where the 5-HTP and carbidopa are both included in the modified release layer. The dosage form provides for essentially parallel release of the 5-HTP and the carbidopa with, for instance, release of 80% of the 5-HTP and carbidopa at about 5 hours to about 12 hours.

Abstract: Disclosed herein are methods of elevating brain extracellular 5-hydroxytryptamine (5-HTExt) and of treating psychiatric conditions and neurological disorders using continuous intravenous infusion of 5-hydroxytryptophan (5-HTP). The methods can be provided for treatment of acute suicidal ideation and/or acute worsening of a mood disorder. The methods can provide rapid onset of therapeutic effect while also having low incidence of acute or moderate adverse effects. Also described herein are compositions for use in the methods, including stable 5-HTP compositions for use in preparing infusate solutions.

Abstract: A gastroretentive, sustained-release dosage form including 5-hydroxytryptophan (5-HTP) as an active ingredient and low-dose carbidopa is described. For example, the dosage form can be provided as a bilayer tablet comprising a swelling layer and a modified release layer, where the 5-HTP and carbidopa are both included in the modified release layer. The dosage form provides for essentially parallel release of the 5-HTP and the carbidopa with, for instance, release of 80% of the 5-HTP and carbidopa at about 5 hours to about 12 hours.