I can speak only for myself but I take one called Coversil in various doses and have never thought it to have any bearing on CH one way or another.

Given that a few of our number here are somewhat mature in years I'm sure many will also help you where they can.

Have a look at Clonidine, which is delivered through a patch. I've not got active CH thanks to D3, but using it hasn't impacted my migraine activity.

I'm not using it for its BP activity, but for another rather painful condition that it is helping to manage.

I had a bit of 'fun' at the weekend which ended up with me in ER most of Saturday, with my BP being measured every few minutes. Most of the time it was around 125/80, but what was interesting was that I had a significant pain spike which took a good dose of morphine to control, which saw my BP spike to 165/95 for a while until the morphine took effect.

The pain increase started before the BP, so at least for me, for one painful incident, it shows that a significant increase in pain levels can result in a significant increase in BP.

This also suggests that reducing your pain levels may also result in a decrease in BP too.

Thanks for the replies folks.

Mike NZ, I have noticed a spike in BP from both CH attack and spikes in pain. Once I had Morphine in ER for a back injury and the protocol was 10ml (I think, I forget due to the morphine) delivered slowly.
The dosing protocol was interesting. I had nurses feed in 1ml into an IV line every few minutes and the ensuing BP drop was watched like a hawk by all present.
Each 1ml they fed into me needed a few minutes and dropped BP significantly so I'm glad they did it this way, slowly.

Batch, you were 100% correct.
I waited to post as I just got back from my GP with no BP drugs, a smile and advice to continue what I'm doing.
I have a cuff and have been using it for about 8 years.
What I will do now is begin a BP diary taken at the same time each day thrice daily and track BP for a while. I was doing this for my Cardiologist, but he suggested I take readings at random times. Over 3 months now tallied up, they average 136/86. "High normal" was today's verdict from my Doctor. No BP meds were prescribed.

This brings me to Magnesium.
Like Mike I've had no break in Migraine activity (Yes, I'm lucky and have the dual diagnosis from a headache specialist) on my D3 regimen.
I went through Mag Oxide, orotate, baths in Sulphate, sprays and a few mix & match Magnesium supplements. My issue with Magnesium is not osmotic diarrhoea or any GI upset at all, it is increased head pain. I know some fellow CHers reading would gladly give up a limb to have Migraine instead of CH attack.
I haven't the foggiest why Mag does this to me, but it does it consistently since my 2011 start on the D3 regimen.

Currently my magnesium dose is 500mg Magnesium Chelate, morning and evening, total 1000mg.
If I raise dose to 1000mg morning and evening (total 2000mg), the head feels like it's going to burst. I can only sustain this Magnesium dose for a few days before I need either Sumatriptan 50mg (which I now avoid) or I drop back the Magnesium to my base dose of 1000mg and the head clears up.

FWIW, the label on my Magnesium supplement reads = Magnesium Amino Acid Chelate 500mg, equiv to elemental Magneium 100mg.
Magnesium equivalents confuse the hell outta me and I know I'm not alone. I can't seem to find any resource specifically on Magnesium equivalents and what they mean.
The Chelate and a handful of cashews seems to be about all I can do for Magnesium after 5 years of experimentation.
Thanks for the recommendations I will keep them at hand should I ever need a BP medication. It is great to get out of the Doctor's without a BP medication, so I'll hit the exercise harder.

Thanks again Gents for your replies.