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Mirtazapine for Sleep: Does it Help?

Mirtazapine (often sold under the brand name Remeron) is a type of tetracyclic antidepressant that’s primarily used to treat depression1 but is also sometimes used off-label to treat other medical conditions, such as insomnia, anxiety, and obsessive-compulsive disorder (OCD).  Off-label2’ means that the drug hasn’t been FDA-approved to treat these conditions, though this doesn’t mean that it’s not effective. 

In this article, we’ll discuss how mirtazapine works, if it’s proven to be helpful for sleep disorders like insomnia, and what sort of side effects you might experience while taking it. We’ll also include tips on how to sleep better without medication.

Does Mirtazapine Help You Sleep?

Mirtazapine is often prescribed off-label by healthcare providers to help treat patients with insomnia.1 Although there’s not a huge amount of evidence3 that supports its use in the treatment of insomnia, the drug is known to have a sedative effect4, which is why doctors might prescribe it to someone who’s having trouble sleeping. 

Treating Insomnia with Mirtazapine

Research published in the Journal of Clinical Sleep Medicine5 showed a significant improvement in insomnia in 22 male patients who took a low dose of mirtazapine at bedtime for eight weeks. 

A small crossover study published in the Journal of Psychopharmacology6 tested a nightly dose of 7.5 milligrams of mirtazapine on 19 male participants. Results showed that the drug reduced the number of nighttime awakenings by 35 to 40 percent, as well as increasing total sleep time by 30 minutes, compared to a placebo.

However, while mirtazapine can be helpful for some people with insomnia, healthcare providers don’t recommend the use of medication alone when treating insomnia, as this does not get to the root of the problem. Mirtazapine should be used alongside good sleep hygiene and cognitive behavioral therapy for insomnia (CBT-I), when appropriate.3

Treating Depression with Mirtazapine

Mirtazapine was approved by the FDA in 1996 for the treatment of depression, and it’s believed the drug works as an antidepressant by increasing levels of mood-enhancing chemicals serotonin and norepinephrine in the brain.1

One uncontrolled clinical study on 93 patients with major depressive disorder showed a significant decrease in depressive symptoms7 after just one week of generic mirtazapine use. Research also suggests that using mirtazapine as the antidepressant of choice can reduce reliance on benzodiazepines8 like Valium or Xanax for insomnia and anxiety in patients with major depressive disorder. 

How Long Does It Take for Mirtazapine to Work?

According to the Cleveland Clinic9, it may take several weeks for you to feel the full benefits of mirtazapine when used to treat depression. Insomnia and anxiety symptoms may be eased shortly after first taking the medication10.

How Long Does Mirtazapine Stay in Your System?

Mirtazapine has an average elimination half-life of between 20 to 40 hours.1 ‘Half-life’ is the time it takes for 50 percent of the medication to be metabolized and excreted from the body. A drug is generally considered eliminated from the body after four to five half-lives11, which is when you should stop feeling the effects.  

Mirtazapine Dosage for Sleep

The recommended dosage of mirtazapine in the treatment of depression is between 15 to 45 milligrams12 a day. However, a lower dosage of between 7.5 to 15 milligrams is usually advised for patients with insomnia who don’t also have depression.5

That said, your specific dosage will ultimately be determined by your healthcare provider.

Side Effects of Mirtazapine

The Mayo Clinic reports that side effects of mirtazapine13 may include drowsiness, dizziness, trouble concentrating, dry mouth, constipation, increased hunger, and weight gain. Daytime drowsiness is the most common adverse effect, experienced by 54 percent of users, with people often reporting feeling similar to being hungover.1 However, this is more pronounced in the first few weeks14 of taking the drug and should begin to wear off as your body gets used to it. 

Healthcare providers recommend taking some time to assess how your body reacts to mirtazapine before driving or operating machinery.13 It’s also advised to limit consumption of alcohol while taking mirtazapine15 as it can increase the sedative effects and cause unsteadiness.

Less common side effects include negative changes in mood, swelling, skin rashes, and trouble breathing. Rare but reported side effects include decreased sexual ability, changes to the menstrual cycle, seizures, sore throat, and fever.13You should never suddenly stop taking mirtazapine without first discussing it with your primary care provider or psychiatrist, as they may advise a tapering schedule to gradually wean yourself off the medication.13

Tips for Better Sleep Without Mirtazapine

Not getting enough quality sleep can be detrimental to both your physical and mental health16, potentially leading to poor concentration, low mood, depression, type 2 diabetes, heart disease, high blood pressure, and obesity. If you’re struggling to fall asleep or stay asleep, there are tactics you can try before turning to medication. 

  • Make your bedroom ideal for sleep – Start by creating an ideal environment for restful sleep by ensuring your bedroom is quiet, dark, and not too hot or cold. The best sleep temperature for most adults is between 60 and 67 degrees Fahrenheit17
  • Avoid alcohol and caffeine – Steer clear of alcohol and caffeinated drinks, which can negatively impact sleep18. Instead, try warm milk or chamomile tea in the evening. 
  • Exercise – Regular exercise can also help improve sleep, specifically boosting the amount of deep sleep19 you get. 
  • Breathing exercises – There is also some evidence that performing slow-breathing exercises20 prior to bedtime can have a positive effect on sleep quality. 
  • Put the tech devices away – Avoid bright screens in the hours leading up to bedtime, as the blue light emitted from smartphones, computers, tablets, and TVs suppresses melatonin production21, the body’s sleep-promoting hormone. 
  • Keep a regular sleep schedule – Having a strict sleep schedule rather than going to bed at a different time each night can also help your body get into a routine. 
  • Consider melatonin supplements – You could also try taking a melatonin supplement, which is available over the counter. However, discuss this with your doctor first, especially if you take other medication. 

When to Talk to Your Healthcare Provider

It’s normal to occasionally struggle with poor sleep. However, if persistent sleep problems make it hard for you to go about your everyday activities, it’s time to speak with your healthcare provider, who will work with you to identify what the problem is. If you’re taking mirtazapine and start experiencing serious side effects or lingering side effects that affect your quality of life, you should seek guidance from your healthcare provider.

Frequently Asked Questions

Is mirtazapine used as a sleeping pill?

Mirtazapine has not been approved by the FDA for use as a sleeping pill, but it’s often prescribed off-label to help patients with insomnia.1 This is because it can cause sedation, especially at low doses, which may help patients fall asleep and stay asleep.4

Is trazodone better than mirtazapine for sleep?

Both trazodone22 and mirtazapine are antidepressants that are FDA-approved to treat depression, and they’re both often used off-label as sleep aids in patients who are experiencing insomnia.

A study23 of 150 patients with chronic insomnia found that both mirtazapine and trazodone were successful at treating the disorder in 60 percent of patients. We all react to medication differently, so it’s hard to say if one is better than the other; your doctor should be able to advise which one might work best for you.

How sedating is mirtazapine?

Mirtazapine is more sedating at lower doses.5 A potential side effect of mirtazapine is daytime drowsiness, especially on waking, which can lead to an initial feeling of being hungover.1 However, excessive drowsiness should subside after a few weeks.14

It’s imperative you avoid driving or operating machinery when first taking mirtazapine until you’ve assessed how much you’re affected by its sedating impact.13

Lisa Bowman

Lisa Bowman


About Author

Lisa is a content writer for Sleep Advisor, which combines two of her greatest passions – writing and sleeping. She can also be found writing about fitness, sustainability and vegan food.

Combination Sleeper


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  2. “Understanding Unapproved Use of Approved Drugs “Off Label”. U.S. Food & Drug Administration. Last modified February 5, 2018.
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  16. “Natural Sleep Aids: Home Remedies to Help You Sleep”. Johns Hopkins Medicine. Webpage accessed January 14, 2024. 
  17. “What’s the Best Temperature for Sleep?”. Cleveland Clinic. 2021.
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  20. Kuula, Liisa., et al. “The Effects of Presleep Slow Breathing and Music Listening on Polysomnographic Sleep Measures – a pilot trial”. Scientific Reports. 2020.
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