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

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

However, this medicine is associated with some side effects including diarrhoea and upset stomach. This blog will cover why mirtazapine acts this way and we are also going to talk about some ways that can help control your frequent watery stools. 

Can mirtazapine cause diarrhoea?

Yes. mirtazapine is associated with diarrhoea. Some people begin to experience this side effect right after taking their first ever dose. However, Mirtazapine can also cause diarrhoea after weeks of using this antidepressant. 

Experts believe that the actual cause of mirtazapine induced diarrhoea is increased motility of the intestine. Mirtazapine belongs to the tetracyclic antidepressants. It has a dual mode of action. 

Mirtazapine is believed to be responsible for the activation of 5-HT1 receptors, which are one of the serotonin receptors. This antidepressant also acts on the noradrenergic system. 

Experts believe that mirtazapine enhances the stimulatory action of the noradrenergic system which increases the secretion of serotonin. It also prevents the inhibitory action of the noradrenergic system which hinders the release of serotonin. 

This excessive serotonergic action also stimulates serotonin receptors in the GI tract. It causes an increase in firing rate of the secretomotor neurons and an increase in intestinal motility and secretion. This increased intestinal motility results in diarrhoea. 

However, several research studies indicate that mirtazapine is actually quite helpful in the management of diarrhoea predominant irritable bowel syndrome (IBS) and many patients have gained benefits from this action of mirtazapine.

A 2021 research study included 34 patients who received mirtazapine and 33 patients were placed in a control group who received placebo. At the end of 7-weeks, it was revealed that patients taking mirtazapine for diarrhoea associated with IBS got significant relief.

In such patients, mirtazapine decreased the frequency of bathroom visits and it also made the consistency of stools less watery. It also helped provide some abdominal pain relief in such patents and controlled their bowel urgencies. 

Make sure you use mirtazapine for all the right reasons and only when your healthcare recommends you to take it. Do not take any more than the prescribed dose. Higher doses are more dangerous and can lead to other disturbing side effects as well. 

Diarrhoea can get pretty disturbing and is associated with symptoms like: 

• Bloating
• Flatulence 
• Abdominal pain
• Malaise 
• Thin or loose stools
• Watery stools
• Nausea and vomiting
• Inability to digest, especially solid foods
• Electrolyte deficiency
• Dehydration
• Weakness 

More serious symptoms include:

• Blood or mucus in your stool
• Hematemesis (bloody vomiting)
• Weight loss 
• Chills and fever

Diarrhoea associated frequent bathroom visits can cause discomforts like:

• Itching.
• Anal fissure
• Burning.
• Pain during bowel movements.

If you’re experiencing any of these discomforts, there are a few things you can do that might help:

• Take a sitz bath.
• Patting your rectal area dry with a clean soft towel. Do not rub it. Avoid scratching it if it itches. 
• Apply fissure cream or petroleum jelly.

Is there any way to get rid of mirtazapine induced diarrhoea?

There are a few treatment options to get rid of mirtazapine induced diarrhoea. Your healthcare provider may suggest one of the following treatments, if needed:

Antidiarrheal agents

Your doctor may prescribe some antidiarrheal agent, which works best with mirtazapine, to treat your diarrhoeal symptoms. The most commonly prescribed agent is loperamide (Brand name: Imodium). 

It slows down the movement of food through your intestines, which lets your body absorb more liquid and makes your stool less watery. Other agents like Kaopectate or Pepto-Bismol (bismuth subsalicylate) are also used. 

A 2000 study suggests that loose watery stools, a common side effect associated with SSRIs, were treated with Alosetron, a medication used to treat irritable bowel syndrome (IBS) in women.

Probiotics

Probiotics should be considered a must, when dealing with meds that upset your stomach. They are actually ‘good’ bacteria which reside naturally in your gut. 

In case of diarrhoea, most of these bacteria are lost because of watery stools. The addition of probiotics will help replenish those good bacteria and bring your stomach back to its normal state. 

Natural sources of probiotics include nuts, yoghurt, asparagus, garlic, onions, leeks, banana, barley, oats, apples, cocoa, wheat bran, flaxseeds etc. Add these in your diet while being on mirtazapine, to strengthen your gut bacteria. 

Electrolyte replenishers

Diarrhoea is strongly associated with dehydration along with loss of electrolytes. This causes extreme weakness, sometimes up to the point where you no longer have energy to even get up from your bed. 

In this condition, it is advised to drink lots and lots of fluids. Electrolyte replenishers are also used which contain various electrolytes like sodium, potassium, chloride ions, bicarbonate ions etc, which might have been eliminated from your body along with your stools.

Oral rehydration therapy is also used. Electrolyte drinks usually contain salts of sodium or potassium, which make up for the amount of these minerals lost from the body.

Other remedies to relieve the symptoms of diarrhoea

Following are a few remedies that can help relieve the symptoms of diarrhoea:

• Drink plenty of fluids like water, oral hydration solutions (ORS), soup etc. 
• Consume liquid calories like milkshakes, smoothies etc. 
• Avoid spicy foods, which can irritate your stomach and exacerbate the symptoms of diarrhoea. 
• Eat plenty of probiotics. In case of diarrhoea, yoghurt is considered a good choice. It cools down your stomach and adds natural probiotics to replenish your lost gastrointestinal microflora. 
• Avoid alcohol and caffeine. 
• Use smecta. Just add one sachet in half a cup of water and drink it. However, drink smecta only when you have passed watery stools more than 3 to 4 times.

Eat foods that are light on your stomach 

People with diarrhoea should eat bland foods, as spicy or complex foods can irritate the bowels. Bland foods that may help with diarrhoea include:

• Banana 
• Applesauce
• Softly boiled white rice
• White bread 
• Boiled or mashed potatoes
• Plain crackers

Avoid foods that are heavy on your stomach

It is best to avoid following foods while experiencing diarrhoea

• Dairy products
• Fried, fatty, greasy foods
• Spicy foods
• Processed foods
• Red meat like veal
• Sardines
• Raw vegetables
• Rhubarb
• Onions
• Corn
• Alcohol
• Coffee
• Soda
• Sorbitol and other artificial sweeteners

When to call your doctor

If your diarrhoea becomes severe, with uncontrollable vomiting and watery stools, immediately contact your doctor. Such conditions might end up needing hospitalisation, especially in case of dehydration. 

Your doctor might suggest IV infusion to replenish your electrolytes. Do not wait for your diarrhoea to subside on its own, as it might not. 

What are the additional side effects of mirtazapine?

The common side effects of mirtazapine include:

• 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 

Mirtazapine is also associated with some serious side effects, which may include:

• Allergic reaction associated with symptoms like redness of skin, itching, burning sensation, blisters, blue-purple patches, tightness of chest, wheezing, difficulty in breathing, hoarseness etc. 
• Convulsions 
• QT prolongation 
• Pain and tightness in chest
• Arrhythmia 
• Flu like symptoms 

These side effects can vary from person to person. People who are on higher doses are more susceptible to these side effects. Report any problems with bleeding or bruising to your doctor. 

If you see any unexplained blisters or rashes on your body, or experience any problems with urination, or if you feel changes in your vision, immediately report to your healthcare provider. 

Mirtazapine come with a suicidal warning in people younger than 24 years of age. If you have someone who shows suicidal behavior or you see hopelessness in them, make sure you keep an eye on them and get medical attention as soon as you can. 

Do not stop this med abruptly. If it’s time for you to stop mirtazapine, your doctor will simply make a taper schedule for you, which should be followed vigilantly if you wish to keep withdrawal symptoms at bay. 

Conclusion

In this blog post, we have discussed mirtazapine induced diarrhoea. We have learned that this antidepressant can cause diarrhoea, but it can be quite helpful in the management of diarrhoea predominant irritable bowel syndrome (IBS) and many patients have gained benefits from this action of mirtazapine.

We have also learned about some ways that can help you get rid of mirtazapine induced diarrhoea fast. Make sure you don’t eat anything that may upset your stomach or exacerbate your symptoms. 

Make sure you use this medication or any other medication only when your doctor has advised it. Using medications which can affect your brain is not something ideal and should not be encouraged unless it is absolutely necessary to do so. 

FAQs: mirtazapine diarrhoea

Can mirtazapine cause diarrhoea?

Yes. mirtazapine is associated with diarrhoea. Some people begin to experience this side effect right after taking their first ever dose. However, Mirtazapine can also cause diarrhoea after weeks of using this antidepressant. 

Can antidepressants cause diarrhoea?

Yes, antidepressants can cause diarrhoea. When antidepressants increase the level of serotonin, they stimulate serotonin receptors in the GI tract as well. It results in increased serotonin activity. It causes an increase in firing rate of the secretomotor neurons and an increase in intestinal motility and secretion. This increased intestinal motility results in diarrhoea. 

Does mirtazapine affect your stomach?

Yes, mirtazapine can affect your stomach in several ways and may cause different side effects in different individuals. Common gastrointestinal side effects include:

• Nausea
• Vomiting
• Diarrhoea
• Abdominal pain
• Constipation

How do you stop diarrhoea from antidepressants?

Your doctor may prescribe some antidiarrheal agent, which works best with your antidepressant, to treat your diarrhoeal symptoms. The most commonly prescribed agent is loperamide (Brand name: Imodium). Other agents like Kaopectate or Pepto-Bismol (bismuth subsalicylate) are also used. 

What medications should not be taken with mirtazapine?

• Monoaminoxidase inhibitors (MAOIs). The combination use can increase the risk of serotonin syndrome. 
• Non-steroidal anti-inflammatory drugs (NSAIDS). The combination use can increase the risk of bleeding. 
• Pimozide. The concomitant use can increase the plasma concentration(availability of a drug in the blood) of pimozide to much higher levels. It can result in life-threatening arrhythmia.
• Controlled substances, including all narcotic analgesics. The concomitant use can cause severe psychological side effects. 
• Mood stabilisers 
• Alcohol 

What are the most common side effects of mirtazapine? 

The common side effects of mirtazapine include:

• 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 

References 

• Katherine F Croom et al. CNS Drugs. (2009) – Mirtazapine: a review of its use in major depression and other psychiatric disorders https://pubmed.ncbi.nlm.nih.gov/19453203/
• S A Anttila et al. CNS Drug Rev. Fall (2001) – A review of the pharmacological and clinical profile of mirtazapine https://pubmed.ncbi.nlm.nih.gov/11607047/
• Mirtazapine Tablet – Uses, Side Effects, and More https://www.webmd.com/drugs/2/drug-13706-4047/mirtazapine-oral/mirtazapine-oral/details#:~:text=Mirtazapine%20is%20used%20to%20treat,(neurotransmitters)%20in%20the%20brain.
• National Library of Medicine – Mirtazapine https://medlineplus.gov/druginfo/meds/a697009.html 
• Alireza Khalilian, Davoud Ahmadimoghaddam, Shiva Saki, Younes Mohammadi & Maryam Mehrpooya (2021) – A randomized, double-blind, placebo-controlled study to assess efficacy of mirtazapine for the treatment of diarrhea predominant irritable bowel syndrome https://bpsmedicine.biomedcentral.com/articles/10.1186/s13030-021-00205-2#:~:text=Further%2C%20compared%20to%20placebo%2C%20mirtazapine,urgency%2C%20pain%2C%20and%20diarrhea.