Valtrex is the branded version of valaciclovir. This means that GlaxoSmithKline, who originally held the patent for valaciclovir, chose Valtrex as its brand name. Until the patent ran out in 2009, only GlaxoSmithKline could sell valaciclovir. Now it can be manufactured by other companies as a generic drug, meaning it can be priced more competitively.