Lin, diltiazem is a calcium channel blocker and that form of drug is known to help in some cases of SOD. They typically use forms of <span style = 'background-color: #dae8f4'>Nitroglycerin</span>
or the blockers to try to tamp down the smooth muscle spasms associated with the condition.
But my question would be have they considered the possibility of residual sludge in the bile duct? Have you discussed doing an MRCP?
As a general rule, any form of narcotic-based medication can raise the pressure in the CBD and will make things worse.