Change your link button like below to pass multiple values as
command argument
.
As you want to pass InteractionName, DrugID and DrugColumn, HTML can be like below,
<asp:linkbutton id="lbtInteractionName" runat="server" xmlns:asp="#unknown">
CommandArgument='<%# Eval("InteractionId") %>, <%# Eval("DrugId") %>,<%# Eval("DrugName") %>'
CommandName="cmdInteractionName"
Text='<%# Eval("InteractionName") %>'></asp:linkbutton>
AND in RowCommandEvent of Gridview, You can get all of the command arguments by splitting based on comma(,). like below.
String[] values = e.CommandArgument.ToString().Split(',');
hope it will help. :)