Dosages of Verapamil for CH patients vary by so much.

Obviously dosages can be increased if not effective for the patient, but the starting dosage is critical as the dr wants it to be effective when the transitional (Prednisone) med is tapered to nothing.  Is starting dosage determined by height/weight/general health/etc?

Does anybody know reasoning of a dr to prescribe 240mg instead of starting at 480 mg, etc?

Yes - If your blood pressure is normal to low. V will lower your blood pressure, so it'd be nice not to keep passing out.

That makes sense Brew.  So if your BP is normal, the dr is most likely to start you at 480mg instead of somebody who already has low BP would most likely start at 240mg?

An enormous % of medical practice is based on what the other guys do. Local patterns of treatment are often remarkably diverse. That being said, this protocol has gained wide acceptance and, as you can see, it designed to obtain best effect with the least dosage. Takes a little time to work up to YOUR effective dose but....
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Headache. 2004 Nov;44(10):1013-8.   

Individualizing treatment with verapamil for cluster headache patients.

Blau JN, Engel HO.

    Background.-Verapamil is currently the best available prophylactic drug for patients experiencing cluster headaches (CHs). Published papers usually state 240 to 480 mg taken in three divided doses give good results, ranging from 50% to 80%; others mention higher doses-720, even 1200 mg per day. In clinical practice we found we needed to adapt dosage to individual's time of attacks, in particular giving higher doses before going to bed to suppress severe nocturnal episodes. A few only required 120 mg daily. We therefore evolved a scheme for steady and progressive drug increase until satisfactory control had been achieved. Objective.-To find the minimum dose of verapamil required to prevent episodic and chronic cluster headaches by supervising each individual and adjusting the dosage accordingly. Methods.-Consecutive patients with episodic or chronic CH (satisfying International Headache Society (IHS) criteria) were started on verapamil 40 mg in the morning, 80 mg early afternoon, and 80 mg before going to bed. Patients kept a diary of all attacks, recording times of onset, duration, and severity. They were advised, verbally and in writing, to add 40 mg verapamil on alternate days, depending on their attack timing: with nocturnal episodes the first increase was the evening dose and next the afternoon one; when attacks occurred on or soon after waking, we advised setting an alarm clock 2 hours before the usual waking time and then taking the medication. Patients were followed-up at weekly intervals until attacks were controlled. They were also reviewed when a cluster period had ended, and advised to continue on the same dose for a further 2 weeks before starting systematic reduction. Chronic cluster patients were reviewed as often as necessary. Results.-Seventy consecutive patients, 52 with episodic CH during cluster periods and 18 with chronic CH, were all treated with verapamil as above. Complete relief from headaches was obtained in 49 (94%) of 52 with episodic, and 10 (55%) of 18 with chronic CH; the majority needed 200 to 480 mg, but 9 in the episodic, and 3 in the chronic group, needed 520 to 960 mg for control. Ten, 2 in the episodic and 8 in the chronic group, with incomplete relief, required additional therapy-lithium, sumatriptan, or sodium valproate. One patient withdrew because verapamil made her too tired, another developed Stevens-Johnson syndrome, and the drug was withdrawn. Conclusions.-Providing the dosage for each individual is adequate, preventing CH with verapamil is highly effective, taken three (occasionally with higher doses, four) times a day. In the majority (94%) with episodic CH steady dose increase under supervision, totally suppressed attacks. However in the chronic variety only 55% were completely relieved, 69% men, but only 20% women. In both groups, for those with partial attack suppression, additional prophylactic drugs or acute treatment was necessary. (Headache 2004;44:1013-1018).

Note last sentence of the second piece.

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SLOW-RELEASE VERAPAMIL

Dr. Sheftell applauded the protocol for verapamil used by Dr. Goadsby and colleagues, which entailed use of short-acting verapamil in increments of 80 mg. “This method was suggested by Lee Kudrow, MD, 20 years ago as an alternative to slow-release verapamil,” Dr. Sheftell noted.

“I would agree with using short-acting verapamil, rather than the sustained-release formulation, in cluster headache,” he said. “I prefer the short-acting formulation with regard to ability to titrate more accurately and safely. My clinical experience anecdotally demonstrates improved responses when patients are switched from sustained-release verapamil to short-acting verapamil.”

Dr. Goadsby agreed that his clinical experience was similar. “There are no well-controlled, placebo-controlled, dose-ranging studies to direct treatment. This is one of those areas where clinicians who treat cluster headache have to combine what modicum of evidence is available with their own clinical experience,” Dr. Sheftell commented.

I think it's also because high dosages cause a shock to the system, which, when that system is your cardiovascular system is never good. 

You're lucky to get a starting dose of 240mg, I'm just about to switch, in about 4 days, to 40mg.  It's going to take me a month to get up to 120mg if I follow doctors orders.   :o

I just started 120 mg/day dosage

As much as I believe in higher doses, I wouldn't start a person start with 480mg - more because of potential arrhythmia problems than reduced blood pressure. But then I'm not a Doc so it doesn't matter what I would do  ;D

My personal experience after 13 years with it, is that the regular release is far more effective for ME and MY CH's - some may not have the same results. (But then some people like 8 lpm O2  ;))

Marc