I want to stress that this is not a cure. My symptoms do not entirely disappear but they are drastically reduced. The most notable effects I experience are a reduction in tachycardia, brainfog, temperature/light/sound sensitivity and fatigue. My sleep quality is also improved. I still experience issues with circulation and have to wear compression stockings, and I notice that I am more mentally alert when laying down as opposed to when sitting/standing upright. My protocol is as follows:
This may not work for everyone. I suspect that the high degree to which this affects me is due to being deficient in the CYP2D6 enzyme. Proficient metabolisers may experience little no relief from symptoms. If people are interested in trying this out, it is likely that the protocol will need to be adjusted.
In those that are proficient metabolisers, I recommend the addition of a CYP2D6 inhibitor. The most easily obtained would be bupropion; sold in Australia as a smoking cessation medication (Zyban) and elsewhere as an atypical, non-SSRI antidepressant (Wellbutrin). A DXM/buproprion combo is also available in the US (Auvelity).
As a poor metaboliser, I am aware of the effects of DXM in my system for up to two days. Paradoxically, when I first take it I experience a temporary worsening of POTS symptoms- issues with temperature regulation (usually high temperature) and tachycardia. I typically take DXM at night and by morning, those side effects subside. Mentally, even at 30mg (the average adult dosage of DXM in OTC cough medication) I experience dissociative effects. It feels like I'm mildly drunk for two days. On the first day, my side effects are the most noticable. On day three they fully wear off and this is when the drastic relief from POTS symptoms begins.
The addition of Naltrexone (2mg) allows me to bypass a great deal of the side effects I experience. It lessens the initial worsening of POTS symptoms and prevents the two day long dissociative effect from kicking in. With the DXM/Naltrexone combo, I feel relief the morning after. I'm not entirely sure of the mechanism behind the synergystic effect here, but Naltrexone does also exert an anti-inflammatory effect at the CNS, which is likely involved. Interestingly, I don't experience relief from POTS symptoms if I take Naltrexone alone.
Naltrexone is an opioid antagonist typically prescribed to those with substance use disorder. In low doses, it has been trialled for Fibromyalgia, ME/CFS and Long COVID and has shown promising results. It can be prescribed off-label by a GP, although it may be hard to come by depending on region.