Why should I avoid tricyclic antidepressants if I have multiple sclerosis?

Tricyclic antidepressants include Elavil (amitriptyline), Tofranil (imipramine), and Pamelor (nortriptyline). These products are not commonly used as first-line agents for multiple sclerosis-related depression because they can cause some annoying adverse effects such as dry mouth, constipation, bladder problems, sexual dysfunction, blurred vision, dizziness, drowsiness and increased heart rate. These can make other multiple sclerosis symptoms feel worse. For treatment-resistant depression, the tricyclic antidepressants are commonly used alone or in combination with other medications.