Has anyone experienced a reduction or remission of postural orthostatic tachycardia syndrome (POTS) or orthostatic intolerance (OI) symptoms after taking a course of antivirals or immunomodulators? ME/CFS itself of course has been linked to a number of viruses, including enteroviruses and herpes family viruses. Herpes family viruses such as EBV, HHV-6, CMV and HSV-1 are often reactivated in ME/CFS patients, and studies have shown that ME/CFS symptoms may improve after taking antiviral drugs for herpes family viruses — drugs such as Valtrex (valganciclovir), Famvir (famciclovir) and Valcyte (valganciclovir). Study references: 1 2 3. Similarly, ME/CFS symptoms may improve after taking antivirals/immunomodulators for enterovirus — such as oxymatrine. I have not seen any studies explicitly showing that herpes family viruses or enteroviruses are reactivated in patients with POTS or OI. But given that these two conditions arise a lot in ME/CFS patients, it seems reasonable to assume that there may be some sort of viral etiology behind POTS and OI. I just wonder if anyone has taken a course of antivirals or immunomodulator drugs, and noticed an improvement in their POTS or orthostatic intolerance symptoms. For example, if you have been regularly measuring the severity of your own POTS by means of the home version of the tilt table test,† has anyone here seen improvements in their POTS severity after a few months of antiviral or immunomodulator treatment? † The home version of the tilt table test is of course just lying down still for ten minutes on your bed, and then noting the increase in heart rate you get when you stand up. An increase in your heart rate of 30 beats per minutes or more on standing gives you a diagnosis of POTS; but even slightly lower increases indicate you have some degree of POTS, and in general, the degree of increase in heart rate indicates the severity of your POTS.