Can mirtazapine cause constipation? (5+ ways to get rid of it faster)

In this blog post, we are going to answer the question, “Can mirtazapine cause constipation?”. Mirtazapine is an antidepressant which is used to treat a variety of mental health conditions. 

However, this medicine is associated with a number of side effects including constipation. This blog will cover why mirtazapine causes this side effect and what could be done to get rid of it. 

Can mirtazapine cause constipation? 

Yes, mirtazapine can cause constipation in some individuals. It is considered a common side effect and is expected to go away within a few weeks as your body adjusts to mirtazapine. 

Many researchers have investigated the effects of mirtazapine on gastrointestinal functions to explain why this medication acts the way it does. Some experts have indicated that many times people misjudge their diet and consider it to be the main culprit behind constipation. 

This made researchers organise a trial in which two groups were made, one control group and the other group was receiving mirtazapine. Both groups were given a healthy diet, the kind which can not lead to constipation in any way. 

It was rich in fibre and a lot of fruits and vegetables were added along with proper hydration. It was observed that the group taking mirtazapine showed some signs of constipation, despite the healthy diet. This confirmed that mirtazapine does cause constipation. 

However, this side effect was not observed in every single participant of the group, but in some. Now, the question circling around researchers’ minds was, ‘how does this actually happen’? 

That’s when they studied the mode of action of mirtazapine in detail to find out the exact mechanism through which this antidepressant causes constipation. 

Several studies revealed that not just mirtazapine, many other antidepressants are also responsible for causing problems in individuals who never really had this problem before. On the other hand, the same antidepressants showed signs of diarrhoea in some individuals. 

This indicated that mirtazapine does not cause the same kind of effects in every individual. Some experts believe that the reason behind mirtazapine causing constipation is the mechanism of action of this antidepressant. 

Mirtazapine, although it is an antidepressant, can be used to treat neuralgia or nerve pain. This indicates that the drug can cause some effects on the nerve endings to make the pain go away. 

Similarly, experts believe that mirtazapine also acts on nerve endings present in your gastrointestinal tract. This effect can decrease your intestinal motility and makes it difficult for you to have a bowel movement. 

This leads to constipation. Several studies indicate that as mirtazapine is an antidepressant, it increases the amount of active serotonin in your body. Serotonin is an excitatory neurotransmitter which has receptors in your gut as well. 

This excessive serotonergic activity in your gut can result in variable effects. It causes diarrhoea in some people and constipation in others. 

Experts believe that meditations are not solely responsible for producing beneficial as well as side effects in our body, and how our bodies respond to them also makes a difference. 

Some people are born sensitive to medications and when they take medications like antidepressants, the excessive chemicals in their brain makes their physiological function act a little differently. They may suffer from heart palpitations, nausea, diarrhoea, constipation, and psychological side effects. 

This is exactly why it is important to inform your healthcare provider if you suffer from any side effects. Mirtazapine may not be the right choice of antidepressant for everyone. 

Proper evaluation is necessary to determine if it’s safe to continue the use of mirtazapine in your case or not. If your healthcare provider believes that there is another antidepressant that can be more beneficial for you then your doctor will switch it. 

Is there anything that can help you get rid of mirtazapine induced constipation? 

There are a few things that can help you get rid of mirtazapine induced constipation or constipation in general. These include:

Over-the-counter laxatives 

The fastest way to have a bowel movement is taking a laxative. Many laxatives are available for use and you don’t need a prescription for that. However, there are some prescription laxatives as well that are usually prescribed when OTC laxatives fail to work. 

There are several agents which work in different ways to stimulate your bowel movements. Laxatives are of different kinds. Some laxatives are bulking in nature. They add more bulk, more volume to the stool and facilitate the passage of stool through the gastrointestinal tract. 

Stool softeners are also used to soften the hard stools. When the stools are hard, they get stuck in your large intestine and stay there for a longer period of time. This leads to more water reabsorption from the stool and it becomes even more hard. 

Such stools can make your condition worse by tearing your anal muscles on their way out. Osmotic laxatives are also used for this kind of condition as these agents make your stool soft by increasing its water content. 

These laxatives, however, can make you dehydrated if you do not drink enough water because they absorb water from your intestinal walls. Other types of laxatives are also used which stimulate the movement of your stools. They basically trigger the process of egestion. 

Drink plenty of water 

Make sure you drink plenty of water, especially if you are taking laxatives or fibre supplements. This is because such agents basically absorb water from your body to add more moisture in your stools. Dehydration is the biggest cause of constipation. 

If drinking water is a challenge for you, you can try adding some fruits in it to make detox water. People usually add lemon, ginger, citrus fruits, and berries to add a refreshing taste to the water. This makes water a little bit interesting and refreshing to drink. 

Several studies have also revealed the importance of sparkling water to provide relief in constipation. However, it is not recommended to drink sweet carbonated beverages as they are not really good for your health. Too much carbonated drinks can trigger acid reflux and cause abdominal pain. 

Add fibre rich foods to your diet 

Fibre is the key to a healthy digestive system. It is important to add more and more fibre rich foods in your diet. It is usually a bulking agent and helps increase the volume of your stool. 

This can help accelerate bowel movement. There are plenty of fruits and vegetables which are excellent sources of fibre. These include:

  • Apples
  • Bananas
  • Spinach
  • Kale
  • Celery
  • Cucumbers
  • Plums
  • Prunes
  • Seeds
  • Lentils
  • Peas
  • Pulses

There are plenty of fibre supplements in case you can meet the need of your daily fibre intake through your diet. Psyllium husk is one of the most commonly used fibre supplements. 

Make sure you take as much as you need. Taking more of it can also cause complications like stomach pain, bloating, gas, feeling of fullness, and loss of appetite. 

Try herbal remedies 

Many herbal remedies have been used over the decades for the treatment of constipation. Senna and rhubarb are amongst the most commonly used herbs to facilitate your bowel movements. 

Several research studies have investigated the safety and efficacy of these agents for the management of constipation. Senna is available in the form of teabags, dried leaves and powder. 

It’s best to be taken with warm water. Senna basically acts on the nerves in your stomach and helps stimulate the bowel movements. 

Avoid sedentarism and stay active 

Inactive lifestyle is one of the most common causes of constipation and muscle weakness. Your intestines have muscles in them, called smooth muscles. These muscles contract and relax to push the faecal matter towards your rectum.

When your lifestyle is sedentary, all your muscles become weak and slow, including your intestinal muscles. When you move or do some kind of cardio exercises, this stimulates your intestinal motility and helps you eliminate the piled up faecal matter fastly. 

Make sure you exercise at least 2 to 4 times a week. It will not only help you with your constipation, but will improve your overall health. 

Drink some coffee 

Coffee is stimulatory in nature and can significantly help boost the intestinal movement in some people. Experts suggest that half a cup to a cup of black coffee can help eliminate faecal matter quickly. Make sure you avoid overusing it. 

Excessive coffee can make you anxious and agitated. It can also mess up your sleep cycle if you drink it at bedtime. It is recommended to not drink coffee 6-8 hours before you go to bed. This is because the half-life of caffeine is around 6 hours and you should not drink it in the evening. 

Increase your probiotic intake

Probiotics are also considered an important key to a healthy gut. These are good bacteria that not only aids in digestion, but also restrict the growth of harmful bacteria that can cause stomach infections. 

Elimination of faecal matter is the last process of digestion and probiotics can significantly help you remove excess faecal matter out of your system. Following foods can help replenish your gut bacteria:

  • Prebiotic rich foods:  They are found in many fruits and vegetables, especially chicory root, artichoke, onion, garlic, asparagus, leeks, banana, and avocado. Grains, such as barley and oats, are also considered good sources of probiotics.
  • Fermented foods: They include sauerkraut, kimchi, kefir, yoghurt, tempeh, miso etc. 


In this blog post, we have talked about mirtazapine induced constipation. It is considered a common side effect and is expected to go away within a few weeks as your body adjusts to mirtazapine. 

However, as long as it stays, it can be managed. We have discussed some ways to help control your constipation. Make sure you consult your healthcare provider if your condition worsens. 

FAQs: mirtazapine constipation 

Does mirtazapine cause constipation?

Yes, mirtazapine can cause constipation in some individuals. It is considered a common side effect and is expected to go away within a few weeks as your body adjusts to mirtazapine. Many researchers have investigated the effects of mirtazapine on gastrointestinal functions to explain why this medication acts the way it does.

What helps constipation from antidepressants?

  • Over-the-counter laxatives 
  • Drink plenty of water 
  • Add fibre rich foods to your diet 
  • Try herbal remedies 
  • Avoid sedentarism and stay active 
  • Drink some coffee 
  • Increase your probiotic intake 
  • Try prunes, dates and figs

Which antidepressants cause the most constipation?

  • Selective serotonin reuptake inhibitors (SSRIs) 
  • Serotonin-norepinephrine reuptake inhibitors (SNRIs) 
  • Tricyclic antidepressants (TCAs) 
  • Atypical antidepressants

What are the most common side effects of mirtazapine?

  • Sleepiness or drowsiness 
  • Excessive tiredness or fatigue 
  • Dizziness or lightheadedness 
  • Xerostomia or dry mouth 
  • Anxiety 
  • Agitation 
  • Confusion 
  • Gain of appetite
  • Weight gain 
  • Gastrointestinal side effects including nausea, vomiting and diarrhoea/Constipation 

Does constipation from antidepressants go away?

Yes, antidepressants induced constipation begins to subside as soon your body becomes adjusted to these meds. This usually happens in around 3 to 4 weeks, depending on the person taking it. 

How long does it take to get used to mirtazapine?

Mirtazapine can take 2-3 weeks to get settled in your body. However, this time duration can vary from person to person. Some people get adjusted to the med earlier than the others. 


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