<p>Levodopa is either converted to dopamine by aromatic-L-amino-acid decarboxylase or O-methylated to 3-O-methyldopa by catechol-O-methyltransferase<sup class="text-reference-group"><a class="reference-popover-link" data-content="Official drug label" href="#label-reference">Label</a>,<a class="reference-popover-link" data-content="Meiser J, Weindl D, Hiller K: Complexity of dopamine metabolism. Cell Commun Signal. 2013 May 17;11(1):34. doi: 10.1186/1478-811X-11-34. (PubMed ID 23683503)" href="#reference-A177745">2</a>,<a class="reference-popover-link" data-content="Elroby SA, Makki MS, Sobahi TR, Hilal RH: Toward the understanding of the metabolism of levodopa I. DFT investigation of the equilibrium geometries, acid-base properties and levodopa-water complexes. Int J Mol Sci. 2012;13(4):4321-39. doi: 10.3390/ijms13044321. Epub 2012 Apr 2. (PubMed ID 22605980)" href="#reference-A177733">3</a></sup>. 3-O-methyldopa cannot be metabolized to dopamine<sup class="text-reference-group"><a class="reference-popover-link" data-content="Elroby SA, Makki MS, Sobahi TR, Hilal RH: Toward the understanding of the metabolism of levodopa I. DFT investigation of the equilibrium geometries, acid-base properties and levodopa-water complexes. Int J Mol Sci. 2012;13(4):4321-39. doi: 10.3390/ijms13044321. Epub 2012 Apr 2. (PubMed ID 22605980)" href="#reference-A177733">3</a></sup>. Once levodopa is converted to dopamine, it is converted to sulfated or glucuronidated metabolites, epinephrine E, or homovanillic acid through various metabolic processes<sup class="text-reference-group"><a class="reference-popover-link" data-content="Meiser J, Weindl D, Hiller K: Complexity of dopamine metabolism. Cell Commun Signal. 2013 May 17;11(1):34. doi: 10.1186/1478-811X-11-34. (PubMed ID 23683503)" href="#reference-A177745">2</a></sup>. The primary metabolites are 3,4-dihydroxyphenylacetic acid (13-47%) and homovanillic acid (23-39%)<sup class="text-reference-group"><a class="reference-popover-link" data-content="Elroby SA, Makki MS, Sobahi TR, Hilal RH: Toward the understanding of the metabolism of levodopa I. DFT investigation of the equilibrium geometries, acid-base properties and levodopa-water complexes. Int J Mol Sci. 2012;13(4):4321-39. doi: 10.3390/ijms13044321. Epub 2012 Apr 2. (PubMed ID 22605980)" href="#reference-A177733">3</a>,<a class="reference-popover-link" data-content="Abrams WB, Coutinho CB, Leon AS, Spiegel HE: Absorption and metabolism of levodopa. JAMA. 1971 Dec 27;218(13):1912-4. (PubMed ID 5171067)" href="#reference-A177805">5</a></sup>.</p><p class="d-none d-sm-block"><strong>Hover over products below to view reaction partners</strong></p>