Preliminary evidence suggests that aciclovir
can reduce the clearance of theophylline
(and therefore possibly aminophylline) by about 30%. Evidence for valaciclovir appears to be lacking although it would be expected to interact similarly.
Evidence appears to be limited. Be alert for an increase in the adverse effects of theophylline
(nausea, headache, tremor) if aciclovir
or valaciclovir is added, and consider monitoring theophylline