CureOrBust, I don't think your links point to the same drug. Cough syrup and antihistamine is a different story.
I am also surprised there hasn't been any trial on antihistamines as MS treatment. One can find questionable treatment with histamins (Prokarin or Procarin) but none for antihistamines against H1 type.
I have following ideas in my mind:
There are four histamine receptors H1, H2, H3, H4 and their blockers. When we speak about antihistamines we think mostly of H1 blockers. In these studies there is some evidence that it could work like it is stated on Wikipedia when looking for Histamine:Histamine therapy for treatment of multiple sclerosis is currently being studied. The different H receptors have been known to have different effects on the treatment of this disease. The H1 and H4 receptors, in one study, have been shown to be counterproductive in the treatment of MS. The H1 and H4 receptors are thought to decrease permeability in the Blood Brain Barrier, thus increasing infiltration of unwanted cells in the Central Nervous System. This can cause inflammation, and MS symptom worsening. The H2 and H3 receptors are thought to be helpful when treating MS patients. Histamine has been shown to help with T-cell differentiation. This is important because in MS, the immune system attacks its own myelin sheaths on nerve cells (which causes loss of signaling function and eventual nerve degeneration). By helping T cells to differentiate, the T cells will be less likely to attack the body's own cells, and instead attack invaders.
For me it means that using antihistamines for H1 and H4 and supporting histamines H2 and H3 could help. So we may give a try to some.
The first generation like benadryl is not for easy to buy in here, so pheniramine or triprolidine could be easier. On the other hand second generation antihistamines like loratadine or cetirizine do not cross BBB, so that raises a question if it is relevant or not.
Colds, flu and other viral or bacterial infections can cause new relapses. Don't these infections increase H1 histamines in our body?http://www.ncbi.nlm.nih.gov/pubmed/16388727http://www.ncbi.nlm.nih.gov/pubmed/22678907http://www.ncbi.nlm.nih.gov/pubmed/20493888
Btw. Prokarin is claimed to be H2 histamine.?