Diltiazem
"Diltiazem was started due to difficulty tolerating flushing of neck, chest and groin with Amylodipine. It has been effective at controlling palpitations but this improvement was not noted immediately after starting medication. It seemed to take over a week after switching from Amylodipine to Diltiazem before relief from palpitations were noted. 

Please note! If you take thyroid hormone replacement, be aware to avoid taking Diltiazem at same time as thyroid medicine.  My thyroid labs (TSH) have been steadily increasing over last 6 months (revealing that my dose of Synthroid has not been adequate) until it was discovered this week that this unwanted change in thyroid labs has been caused by taking Diltiazem daily at same time as Synthroid."