Aciclovir does not normally seem to affect
ciclosporin levels nor worsen
renal function, but a very small number of cases of nephrotoxicity and increased
ciclosporin levels have been seen following concurrent use. Valaciclovir, a prodrug of
aciclovir, is expected to interact similarly.
The handful of cases where problems have arisen clearly indicate that
renal function should be well monitored if both drugs are given. The manufacturers of valaciclovir recommend that
renal function is closely monitored if high doses (more than 4 g daily) are given with
ciclosporin.