What should I know about tricyclic antidepressants?

Tricyclic antidepressants, or TCAs, are used to prevent migraines. They can decrease the frequency, severity, and duration of a migraine. The amount prescribed varies from person to person.

TCAs are commonly taken once a day at bedtime. Your doctor will start you off with a low dose and increase the dose slowly every 1 to 2 weeks. Typically, people respond within 10 days. But the best results may not occur until after you've taken the medication for 4 to 8 weeks.

How do tricyclic antidepressants work?

TCAs work by increasing the chemicals norepinephrine and serotonin in the brain. When these levels are low, there is a greater chance of migraines. So when the level is raised, there is less chance.

What are the possible side effects from using tricyclic antidepressants and what should I do about them?

Common side effects from TCAs include:

  • agitation
  • anxiety
  • blurred vision
  • constipation
  • difficulty urinating
  • dizziness when standing, called orthostatic hypotension
  • drowsiness
  • dry mouth
  • dry skin
  • fast heart rate
  • fatigue
  • increased appetite
  • muscle twitches
  • nervousness
  • sedation, feeling medicated or sleepy
  • sexual dysfunction
  • sweating
  • weight gain

If you experience any of the following symptoms, you must seek immediate medical attention.

  • altered liver function
  • asthma - worsening of symptoms
  • glaucoma - worsening
  • irregular heartbeat, called cardiac arrhythmia
  • loss of consciousness
  • overdose - potentially fatal
  • rashes or other allergic reactions
  • seizures

On the next page, learn about possible drug interactions with TCAs.

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