The Verap dose is much lower than most of use need. This article has become a standard protocol and you will see how much is often required. Suggest you print this for your doc. The source and author are mainline medical.
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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).
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For your learning:
Cluster headache.
From: Multimedia File Viewing and Clickable Links are available for Registered Members only!! You need to

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(Orphanet Journal of Rare Diseases)
[Easy to read; one of the better overview articles I've seen. Suggest printing the full length article--link, line above--if you are serious about keeping a good medical library on the subject.]
Leroux E, Ducros A.
ABSTRACT: Cluster headache (CH) is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes) of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye). It affects young adults, predominantly males. Prevalence is estimated at 0.5-1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name) in bouts that can occur during specific months of the year. ALCOHOL IS THE ONLY DIETARY TRIGGER OF CH, STRONG ODORS (MAINLY SOLVENTS AND CIGARETTE SMOKE) AND NAPPING MAY ALSO TRIGGER CH ATTACKS. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH IS ASSOCIATED WITH TRIGEMINOVASCULAR ACTIVATION AND NEUROENDOCRINE AND VEGETATIVE DISTURBANCES, HOWEVER, THE PRECISE CAUSATIVE MECHANISMS REMAIN UNKNOWN. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms) has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments) and to reduce the number of daily attacks (prophylactic treatments). Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the hypothalamus and greater occipital nerve stimulators have been tried in experimental settings.THE DISEASE COURSE OVER A LIFETIME IS UNPREDICTABLE. Some patients have only one period of attacks, while in others the disease evolves from episodic to chronic form.
PMID: 18651939 [PubMed]