Using a framework in which all elements are constrained by Dyson-Schwinger equation studies in QCD, and therefore incorporate a consistent, direct and simultaneous description of light-and heavy-quarks and the states they constitute, we analyze the accuracy of SU(4)-flavor symmetry relations between pi rho pi, K rho K, and D rho D couplings. Such relations are widely used in phenomenological analyses of the interactions between matter and charmed mesons. We find that while SU(3)-flavor symmetry is accurate to 20%, SU(4) relations underestimate the D rho D coupling by a factor of 5.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)