I checked for drug
interaction between Synthroid (levothyroxine)
and nortriptyline, but there is only minor
interaction reported.
However, a potentially life threatening condition called serotonin syndrome may occurred with nortriptyline, either taken alone or with MAOIs (or monoamine oxidase inhibitors) and/or other serotonergic drugs, such as triptans, tricyclic antidepressants, tramadol, and etc.