  In this work we state conditions for a current Lie algebra $\g \otimes
\mathcal{S}$ to admit an invariant metric, where $\g$ is a quadratic Lie
algebra and $\mathcal{S}$ is an associative and commutative algebra with unit.
We also consider the reciprocal: if $\g \otimes \mathcal{S}$ admits an
invariant metric, we state necessary and sufficient conditions for $\g$ to
admit an invariant metric. In particular, we show that if $\g$ is an
indecomposable quadratic Lie algebra, then $\g \otimes \mathcal{S}$ admits an
invariant metric if and only if $\mathcal{S}$ also admits an invariant,
symmetric and non-degenerate bilinear form. In addition, we prove a theorem
similar to the double extension for $\g \otimes \mathcal{S}$, where $\g$ is an
indecomposable, nilpotent and quadratic Lie algebra.
