1. Adjunctive 5-Hydroxytryptophan Slow-Release for Treatment-Resistant Depression: Clinical and Preclinical Rationale
- Author
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Jacobsen, Jacob PR, Krystal, Andrew D, Krishnan, K Ranga R, and Caron, Marc G
- Subjects
Pharmacology and Pharmaceutical Sciences ,Biomedical and Clinical Sciences ,Clinical Sciences ,Depression ,Mental Health ,Neurosciences ,Brain Disorders ,Development of treatments and therapeutic interventions ,5.1 Pharmaceuticals ,Mental health ,5-Hydroxytryptophan ,Animals ,Antidepressive Agents ,Second-Generation ,Delayed-Action Preparations ,Depressive Disorder ,Treatment-Resistant ,Humans ,Serotonin ,Serotonin Plasma Membrane Transport Proteins ,Selective Serotonin Reuptake Inhibitors ,5-hydroxytryptophan ,Antidepressant ,depression ,treatment-resistant depression ,Biological Sciences ,Medical and Health Sciences ,Pharmacology & Pharmacy ,Pharmacology and pharmaceutical sciences - Abstract
Serotonin transporter (SERT) inhibitors treat depression by elevating brain extracellular 5-hydroxytryptamine (5-HTExt). However, only one-third of patients respond adequately. Treatment-resistant depression (TRD) is a major unmet need. Interestingly, elevating 5-HTExt beyond what is achieved by a SERT inhibitor appears to treat TRD. Adjunctive administration of 5-hydroxytryptophan (5-HTP) safely elevates 5-HTExt beyond the SERT inhibitor effect in humans; however, 5-HTP cannot be a clinically viable drug because of its poor pharmacokinetics. A slow-release (SR) delivery mode would be predicted to overcome the pharmacokinetic limitations of 5-HTP, substantially enhancing the pharmacological action and transforming 5-HTP into a clinically viable drug. Animal studies bear out this prediction. Thus, adjunct 5-HTP SR could be an important new treatment for TRD. Here, we review the clinical and preclinical evidence for this treatment.
- Published
- 2016