It's difficult to find any information on long-term side effects
. As Orchid said, DPH is not that popular. Scientific and medical sites assume that one is using it according to the instructions on the label. It's even tough to find information on long-term side effects of medical doses. No one seems to know the LD50
in humans, just that it's 500mg/kg in rats. An article on schoolnurse.com claims that the human "lethal dose" is 2.8g, but the article doesn't say whether this is LD10 or LD50 or what...and I don't know how reliable that site is anyway, having never heard of it before.
is particularly interested in this because he often - nearly every day - takes several 50mg doses for his horrid allergies. We may not know for sure, but we might be able to make an educated guess based on how our bodies work and what DPH does to them.
It plugs histamine receptors, which I think would leave more histamine floating around in the bloodstream. Over time, chronic use might lead one's body to release extra histamine in an attempt to get back to baseline. I'm not sure what high histamine can do to a person aside from anaphylactic shock and high adrenalin levels, which I doubt would happen. I'd be willing to bet it would cause something autoimmune, however - allergies, at least.
DPH inhibits the uptake of serotonin
- like modern antidepressants
was derived from it), but not as dramatic. Chronic DPH use might have affects similar to (but probably less powerful than) chronic SSRI