Amitriptyline can cause common but bothersome side effects like drowsiness, dry mouth, dizziness, constipation, blurred vision, confusion, and weight gain. More serious side effects are less common but can include fast or irregular heartbeat, fainting, seizures, trouble urinating, eye pain or vision changes, yellow skin/eyes, and severe mood changes.

Common side effects

These are the ones people most often notice:

  • Drowsiness or feeling “foggy”.
  • Dry mouth.
  • Dizziness or lightheadedness, especially when standing up.
  • Constipation.
  • Blurred vision.
  • Weight gain or increased appetite.

More serious side effects

Get medical help urgently if you have:

  • Fast, pounding, or irregular heartbeat.
  • Fainting, severe confusion, hallucinations, or seizures.
  • Trouble peeing or not being able to pee.
  • Eye pain or sudden vision changes.
  • Yellow skin or eyes , which can suggest a liver problem.
  • Bleeding, bruising, or fever with sore throat , which can signal blood problems.

Important caution

Amitriptyline can also cause withdrawal symptoms if stopped suddenly , so it’s usually better to taper it with a clinician’s guidance.

If you want, I can also list the side effects in plain-English “common vs dangerous” form or help you understand which ones need urgent care.