Results of a study of high-dosage (8 g/day) valaciclovir and its relation to cytomegalovirus (CMV) disease show that 15 percent of subjects developed complications of CMV disease. Although some subjects developed CMV disease (12 percent) during valaciclovir treatment, the study reveals that there was an overall 33 percent reduction in the development of CMV in people using the drug. Gastrointestinal complaints occurred more often and earlier with subjects using valaciclovir rather than acyclovir. Also, signs of thrombotic microangiopathy occurred significantly more often in valaciclovir users versus acyclovir users. Reduced survival rates compared to acyclovir were noted, although this could be a result of too high of a dose of valaciclovir being administered.