What are the side effects of Doxepin (Sinequan) and Pregabalin (Lyrica)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: March 7, 2025 • View editorial policy

From the Guidelines

Doxepin and Pregabalin can cause significant side effects, including sedation, dizziness, and weight gain, and patients should be closely monitored for these effects, especially when taking these medications together. The side effects of Doxepin (Sinequan) include drowsiness, dry mouth, blurred vision, constipation, urinary retention, and weight gain, as well as more serious effects like increased heart rate, confusion, and worsening of glaucoma 1. Pregabalin (Lyrica) commonly causes dizziness, drowsiness, weight gain, peripheral edema, and blurred vision, with the efficacy and tolerability of pregabalin seeming to be similar to those of gabapentin, but with linear pharmacokinetics and more straightforward dosing 1. Some key points to consider when prescribing these medications include:

  • Starting with lower doses and titrating slowly, especially in geriatric patients, to minimize side effects 1
  • Monitoring patients for signs of sedation, especially when first starting treatment or after dose increases, and advising them to avoid driving or operating machinery until they know how these medications affect them
  • Being aware of the potential for enhanced sedative effects when these medications are taken together, and carefully managing dosing to minimize this risk
  • Educating patients on the importance of reporting concerning side effects to their healthcare provider immediately, and never stopping these medications abruptly to avoid withdrawal symptoms. It's also important to note that the combination of these medications may require careful management, and patients should be closely monitored for signs of adverse effects, especially elderly patients who may be more sensitive to these effects 1.

From the FDA Drug Label

Pregabalin may cause serious side effects, including:

  • Muscle problems, muscle pain, soreness, or weakness.
  • Problems with your eyesight, including blurry vision.
  • Weight gain.
  • Feeling "high". The most common side effects of pregabalin in adults are:
  • Dizziness
  • Blurry vision
  • Dry mouth
  • Weight gain
  • Sleepiness
  • Trouble concentrating
  • Swelling of hands and feet

The FDA drug label for Pregabalin (Lyrica) lists the following side effects:

  • Serious side effects: muscle problems, vision problems, weight gain, and feeling "high"
  • Common side effects in adults: dizziness, blurry vision, dry mouth, weight gain, sleepiness, trouble concentrating, and swelling of hands and feet
  • Common side effects in children: weight gain, increased appetite, and sleepiness

There is no information in the provided drug labels about the side effects of Doxepin (Sinequan). 2, 3, 4

From the Research

Side Effects of Doxepin (Sinequan)

  • Common side effects of Doxepin include dry mouth, drowsiness, and constipation 5
  • Postural hypotension is uncommon, but Doxepin can cause intrinsic cardiotoxicity in overdosage similar to other tricyclics 5
  • Low-dose Doxepin can cause headache and somnolence as the most common side effects 6
  • Doxepin tends to cause fewer or less troublesome side-effects than other tricyclic antidepressants such as imipramine and amitriptyline 5

Side Effects of Pregabalin (Lyrica)

  • Common side effects of Pregabalin include dizziness, somnolence, and weight gain 7
  • The potential for abuse of Pregabalin is low, and the risk of withdrawal symptoms is generally low when the drug is discontinued gradually 7
  • Pregabalin is generally well tolerated, with a distinct mechanism of action and a rapid onset of effect 7

Comparison of Side Effects

  • Both Doxepin and Pregabalin can cause somnolence as a side effect, but the overall side effect profile differs between the two medications 5, 6, 7
  • Doxepin is more likely to cause anticholinergic side effects such as dry mouth and constipation, while Pregabalin is more likely to cause dizziness and weight gain 5, 7

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.