I've posted multiple times about verapamil which is one of the more commonly used CH preventives. So to bring my current knowledge into a single post...

Varapamil is a calcium channel antagonist, which means that it modifies the behaviour of how calcium ions are moved across the cell membranes throughout our bodies. This is know to result in blood pressure reduction which is what the medication was originally used for, however it was found to also result in reducing the number of CHs that someone gets, hence it is known as a CH preventive.

The typical dose for someone to get an effective CH preventive response for CH is between 360mg and 480mg a day, however some will see a notable reduction at a lower dose whilst others may go to around 1000mg a day. This is a significantly higher dose than is normally used for blood pressure reduction, which can explain why some doctors who are not experienced with CH can be reluctant to go to these high doses.

The actual dose that someone can go to will be where there is a balance between how effective verapamil is as a preventive and the side effects from taking the medication. There may also be factors as a result of a person's medical history. So whilst the doses mentioned in the previous section are typical ones, what an individual can take may not always match the doses mentioned.

When starting on verapamil, it is normal to start at a lowish dose, say 120mg or 240mg a day and to gradually increase the dose over time until there is a suitable reduction in the number of CHs compared to the side effects or the maximum dose.

When changing dose it typically takes 7-10 days for the dose change to become effective, so people should allow about 14 days to see if it is working well for them. Changing doses any quicker may mean you taking more verapamil than you need or giving up thinking that it isn't working.

There are also two types of verapamil, one is instant release which as the name suggests resulting in the verapamil being absorbed rapidly. The other is sustained release which means that the dose is released into the body over a number of hours. Some people have found success with one or the other (or both), with no obvious predictor as to what will work for someone, so people may need to try both options if one doens't work, with the instant release one being the more commonly reported one giving positive results.

The verapamil dose is normally split into three doses during the day. Whilst this is normally split equally, e.g. for 360mg a day to take 3 x 120mg, this isn't always followed.

The half life of verapamil after multiple doses has been reported as 4.5 to 12.0 hours, so assuming the mean value is about 8 hours, the dose can be split to give more of the dose about 8 hours prior to when a person gets most of their CHs. So someone getting most of their CHs overnight might take a slightly higher dose with their evening meal and lower doses with breakfast and lunch.

The more common side effects reported here with verapamil are constipation and reduced blood pressure, especially for those who already have low blood pressure.

Another potential side effect is that it can change the PR interval on an ECG, which is recording the electrical activity of the heart. It is recommended that people on verapamil have regular ECGs, especially when increasing their doseage. People should work with their doctor around any dose changes and ECGS. Normally if the PR interval is affected then stopping verapamil should result in the PR interval returning to normal.

Whilst it is more straightforward for someone who is chronic to just keep taking a dose which is effective for them, for someone who is cyclic it can depend on how regular their cycle is as to when to start / stop using it. If somone gets a cycle that starts every September and lasts for 4 weeks, they could start taking it in August and stopping at the start of November, which allows time for it to build up and some leeway for an early / late start / stop.

For those who have more unpredictable cycles, they can start taking verpamil when the cycle starts, however to cover the 7-10 days for verapamil to become effective it is common for a prednisione taper dose to be given. This will start at about 70mg a day for around 3 days, then reducing by 10mg a day. This should work as a short term effective preventive.

Prednisione is not normally used for the medium to long term as there is a risk of joint damage.

As to when to stop taking a preventive, this could be once there has been no CH symptoms for a while or when past when a cycle normally stops. An alternative is the "beer test", since for most people with CH a beer will bring on an immediate CH. So if you try a beer (ideally at home) and you don't get a CH then your cycle is probably over. But make sure you've abortives to hand in case a CH comes on.

Note that I'm not a medical doctor and that you should work with your own doctor around any CH medication, dose changes   and anything related.

Yes Mike good summary of a v useful drug; easily absorbed (pun intended)

Verapamil obviously is very effective on some and as is typical with CH not so on others, then there are those that can’t tolerate the stuff

But its the point on Instant / Sustained / Slow / Modified etc etc Release that I would like to pick up on.

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The lag times are crucial when targeting an intermittent condition. The fact that some formulations work (for some) and other formulations don’t (for the same people) is not that surprising

And this is where the importance of pharmacology comes into CH mix. Its complex stuff and GP’s can’t be expected to understand the full implications of the formulations they are dishing out. Verapamil is Verapamil is Verapamil. So there is not much hope for the average sufferer, even a phD in a pharma discipline isn’t going to make understanding the totality of all the concomitant interactions easy.

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The above link is interesting to me because of the use of electrolytes in the formulation to adjust the    longevity of effectiveness.

Hey Mike,

Great work, as always.

I have never been on Verapamil. My Doctor was intending to start me a couple of years back, but I asked him to read Batch’s D3 Regimen paper first.

He felt it had merit (hadn’t heard of it before) and was worth trying first.

As a result,  I haven’t needed to take Verapamil since, long may that last.

Peter.

A great article and certainly fits with my experience. Except I have taken it full time for years.

Verapamil has worked for me in varying degrees. When I first started taking it last January at 3X 40mg it either helped end my cluster or considered with the natural ending of the cluster. I noticed a definite decrease of CH attack intensity while on verapamil.

I just posted this over in "Getting to know ya" but my experience with my current cluster is as follows:  My doctor ramped me up to 180mg ER of verapamil and then to 240mg. 240 seemed to help but I started experience side effects in the form of headaches all day and major fatigue (could not function). Back at 180 the CH kicked in again. As before, the attacks are much milder with the verapamil.