I'll bet you're right about the Verapamil. This is a list of side effects from Mayo's information page:

Verapamil Oral

I have a brain injury from encephalitis a car accident and the best thing I have found for the headaches is low dose Benadryl (children's dose of 5 ml every 4-6 hours) and an amino acid called L-Histidine which helps with inflammation. Taking a lower dose of Benadryl keeps you from getting sleepy.

I'm glad the site is helpful!

Jan

Type of Myotonia: Thomsen's

Country: US