<p>In vivo drug-drug interaction studies were not conducted with valganciclovir. However, because valganciclovir is rapidly and extensively converted to ganciclovir, drug-drug interactions associated with ganciclovir will be expected for Valganciclovir. Drug-drug interaction studies with ganciclovir were conducted in patients with normal renal function. Following concomitant administration of Valganciclovir and other renally excreted drugs, patients with impaired renal function may have increased concentrations of ganciclovir and the coadministered drug. Therefore, these patients should be closely monitored for toxicity of ganciclovir and the coadministered drug.</p>