High Dose Verapamil Problematic in Cluster Headache Treatment

Patient Expert

by Teri Robert, MyMigraineConnection Lead Expert

Cluster headaches are often said to be the most painful of all headaches. They have been described as "boring," bearing, burning," "like a hot poker in the eye," and as "suicide headaches."

Verapamil, a calcium channel blocker frequently used for Migraine and headache prevention - increasingly for cluster headache, was recently studied in high doses for cluster headache prevention.

Study Background

The use of high dose verapamil has become increasingly common for the prevention of CH, with higher doses than used for heart conditions and hypertension needed. Side effects include atrioventricular block and bradycardia*, although how frequently they occur in CH patients is not clear. There are no formal guidelines for the use of verapamil for CH. The authors of this study have developed a protocol, keeping in mind the potential for cardiac complications and reviewed the use of the protocol and the changes seen in EKG readings.

Study Method

The charts of patients with episodic cluster headache (ECH) or chronic cluster headache (CCH) attending the Headache Clinic at the National Hospital for Neurology and Neurosurgery from September, 2001, to September, 2005, were reviewed. Patients had a diagnosis of CH consistent with the second edition of the International Classification of Headache Disorders made by at least one doctor at the Headache Clinic.


  • Patients with CH were started on 240 mg of verapamil daily.
  • The dosage was increased by 80 mg every 2 weeks and an EKG performed until the CH was suppressed, side effects intervened, or to a maximum daily dose of 960 mg.
  • EKGs were performed after 2 weeks to account for the time taken for the effect of verapamil dose changes to settle.
  • EKGs were performed either on the hospital site or by local practitioners if the distance from the clinic and travel were difficult.
  • One patient had 1,000 mg and one had 1,200 mg daily by their own decision.
  • The ordinary release formulation of the medicine and not the controlled release formulation were used.

Study Results

  • 217 outpatients (175 men) received verapamil, starting at 240 mg daily and increasing by 80 mg every 2 weeks with an EKG, until the CH was suppressed, side effects intervened, or to a maximum daily dose of 960 mg.
  • One patient had 1,200 mg/day.
  • 89 patients (41%) had no EKGs.
  • 108 patients had EKGs in the hospital; 20 had EKGs done elsewhere.
  • 21 of 108 patients (19%) had arrhythmias.
  • 13 (12%) had first-degree heart block, at 240 to 960 mg/day, with one requiring a permanent pacemaker.
  • Four patients had junctional rhythm, and one had second-degree heart block.
  • Four patients had right bundle branch block.
  • 39 patients (36%) experienced bradycardia (heart rate less 60 bpm), but verapamil was stopped in only 4 patients.
  • In eight patients the pulse rate interval was lengthened, but not to less than 0.2 s.
  • The incidence of arrhythmias (disturbed heart rhythms) on verapamil in this patient group is 19% and bradycardia 36%.

Study Conclusion

"We therefore strongly recommend EKG monitoring in all patients with cluster headache on verapamil, to observe for the potential development of atrioventricular block and symptomatic bradycardia." 1


Cluster headache can be a devastating and debilitating condition. As with Migraine, there have been no medications developed specifically for prevention, and medications such as verapamil are prescribed off-label.

Dr. Goadsby's comments summarize the risks and benefits of high dosage verapamil for cluster headache quite well:

"The good news is, when you stop the drug, the effect wears off," said study lead author Dr. Peter Goadsby, professor of neurology at University College London. "So, as long as doctors know about it, and patients with cluster headaches on verapamil know they need EKGs done, it is a completely preventable problem." 4

"The benefit of taking verapamil to alleviate the devastating pain of cluster headaches has to be balanced against the risk of causing a heart abnormality that could progress into a more serious problem." 5

  • A condition in which the electric conduction of nerve impulses to specialized muscles in the heart is slowed or interrupted. 2

** A heart rate that's "too slow" is called bradycardia. What's "too slow" depends upon a person's age and physical activity. 3


1 Cohen, Anna S., MRCP, PhD; Matharu, Manjit S. MRCP, PhD; Goadsby, Peter J. MD, PhD, DSc. "Electrocardiographic abnormalities in patients with cluster headache on verapamil therapy." _Neurology_® 2007;69:668-675.

2 "What Is a Heart Attack?" MyHeartCentral.com.

3 "What Are Arrhythmias?" American Heart Association.

4 Perkel, Jeffrey. "Cluster Headache Treatment Poses Cardiac Dangers." HealthDay. August 13, 2007.

5 "Verapamil for headaches may cause heart problems." Reuters Health. August 13, 2007.

Last updated August 14, 2007.