Montelukast and Irritability: What Users Say

• Ang...
• March 9, 2020

Montelukast for Asthma "Be careful! After years of being misdiagnosed, I was given Singulair. Within 4 weeks, I no longer needed my nebulizer or rescue inhalers. I gradually became more tired and extremely agitated. I began hearing voices in my own home, and I live alone. It got worse, not better. One night, I was convinced someone was in my home. Every light in the house was on. I still kept seeing someone! Coming from a military background and secure in owning firearms, I was searching my home with a gun. I was looking for an intruder who was NOT there! That was my final straw. I threw my Singulair in the garbage. I’m still agitated and frustrated. I am going to try over-the-counter medication deemed safe. I’m not sure how long the agitation and tiredness will last. I pray this will help someone. Please be careful on this medicine. For me, it’s not worth it. In 55 years, I’ve never seen anyone or heard voices in my home until Singulair. (5 weeks total taking it)"

• San...
• Taken for 1 to 6 months
• April 19, 2020

Montelukast for Allergic Rhinitis "I was given this medication, Singulair, for chronic nasal congestion and rhinitis. After about 2 months, I started to notice my mood changing. I was more argumentative, almost to the point of aggression. When I started to have bizarre dreams, I then researched the side effects of this drug. Here is what was listed: mental/mood changes (such as agitation, aggression, anxiety, trouble sleeping, abnormal dreams, sleep-walking, memory/attention problems, depression, hallucinations, thoughts of harming yourself/suicide). I immediately stopped taking this medication (it wasn't helping that much anyway) and these side effects have stopped completely. PLEASE be mindful of ALL the side effects of any medications you are taking! I never would have believed that something to help with nasal congestion could cause such problems."

• Mad...
• Taken for 2 to 5 years
• November 2, 2020

Montelukast for Asthma "While on this medication, my asthma and allergies were almost non-existent. However, I also developed severe depression that almost took my life, anxiety, became easily agitated, and had pain in my mouth and back. Since I stopped, I feel happier, more patient, less sore, but my allergies have come back. If it weren't for the side effects, I would have kept taking it."

• Kdu...
• Taken for less than 1 month
• March 31, 2015

Montelukast for Asthma "Started Singulair approximately 1 week ago. I will say it's an asthma miracle, but the side effects are unreal. I had extreme irritability (out of character for me), severe fatigue when normally active, mood changes, depression, anxiety. I wish doctors would really explain this to new users. Thanks to all of you who reviewed this medicine and gave me insight on what was going on, that's the reason for my post too."

• Sco...
• Taken for less than 1 month
• June 14, 2018

Montelukast for Allergic Rhinitis "This drug is not for everyone. I took it for just three days and got very depressed, even to the point of having really dark thoughts, had a constant headache, an upset stomach, deep soreness in my teeth, mood swings, and irritability. However, it did help my allergies. Be very conscious of how you feel when you try this drug."

• MM ...
• Taken for 5 to 10 years
• October 10, 2018

Montelukast for Allergic Rhinitis "I am a parent of two children. Both children took Singulair for allergies. Both children had issues while taking Singulair and experienced withdrawal effects once I stopped the medication. My daughter developed tics, tremors, anger, rage, OCD, anxiety, mood swings, and agitation, to name a few side effects. My son developed frequent urination, muscle issues, joint pain, and sadness. Both my children developed a hypersensitivity to all artificial sweeteners, dyes, and all emulsifiers/preservatives as the inactive ingredients are made up of most of these items. Their hypersensitivity to artificial sweeteners, dyes, and emulsifiers/preservatives still continues even though they stopped the medicine."

• Ver...
• November 5, 2016

Montelukast for Asthma "Since taking Singulair I have tooth pain, tingling in my face, and a bad metallic taste in my mouth. Plus my anxiety level went up, feel really tired, and very agitated. Stopped taking it last night. Hope these side effects go away soon. This metallic taste is driving me crazy! This is the 2nd time I've tried it. Same side effects and more."

• Cyn...
• Taken for less than 1 month
• August 28, 2022

Montelukast for Allergic Rhinitis "My dr warned me Singulair had a black box warning due to sometimes causing depression and suicidal symptoms, but I wasn’t concerned. I am a psychotherapist and don’t usually have side effects to meds. Shortly after taking Singulair, I began to feel agitated and depressed. I felt negative and paranoid. Then one day I thought, “What is the point of living?” I remembered my dr mentioning the black box warning and stopped taking Singulair. My mood improved dramatically each day I was off Singulair. Please be careful."

• Sti...
• Taken for less than 1 month
• April 23, 2016

Montelukast for Allergic Rhinitis "I tried Singulair because I have nasal allergies that turn into nasty sinus infections every couple of months. I also have panic disorder, but it's well controlled with medication. I was only able to take Singulair for 4 days due to side effects, so I can't say how well it works. It made me so sleepy that I was sleeping 12-15 hours a day and still tired when I was awake. I haven't had a panic attack in over a year, and my anxiety went through the roof on this stuff. My panic attacks were so bad that I was having trouble driving. I was also moody and irritable the days I took it. Luckily, all of the negative side effects went away within a couple of days of stopping Singulair. Stay away from this drug if you are prone to anxiety!!!"

• Gco...
• October 19, 2016

Montelukast for Allergic Rhinitis "My wife was on this stuff for at least a couple of years. She suffered severe tiredness, nightmares, irritability, and even suicidal thoughts, accompanied by severe depression! Although it did make her feel better, the side effects are not worth it at all! She switched to Flonase, and it is just as good. Please, if you are on this medicine and have any of these side effects, please stop!"

• Nor...
• March 27, 2016

Montelukast for Asthma, Maintenance "I have mild asthma that occasionally worsens to be more moderate. I'm another person who has mood effects from taking Singulair, and in addition, it's affecting my ability to enjoy certain flavors. It feels like an antihistamine, sort of, causing my mouth to feel dry, and I feel thirsty a lot. I'd live with that, but I am experiencing this weird agitation that's quite uncomfortable. I'm very aware of it, and I'm an adult, not a kid, so I probably won't bite anybody's head off. However, I think it might not be worth it to me, and I think I'll stop it for a few days to compare how I feel then with what I'm feeling now."

• Anonymous
• January 6, 2012

Montelukast for Allergic Rhinitis "Yes, I think this medicine works in treating allergic rhinitis, but after not being able to sleep at all the night I took it and being extremely agitated with mood swings tapering off into the next day after a full night's sleep, I will take it no more. I think each person needs to weigh the benefits versus the side effects for them. Everyone is, of course, different and each responds in their own way to all of these medicines. Just monitor your reaction to the drug closely if you do decide to use it and make the right decision for you to continue it or not."

• Ksu...
• Taken for 1 to 6 months
• September 17, 2018

For Asthma "I have been taking montelukast for three months. I persisted with the vivid nightmares, irritability, anxiety, and depression because it was so effective for my asthma. Family, friends, and work colleagues noticed my mood change and my inability to be happy. The weight gain was another unwanted side effect. The prolonged and worsening side effects have forced me to stop taking it."

• Anonymous
• May 17, 2011

Montelukast for Allergic Rhinitis "I had constant sinus infections caused by allergies. Tried several medications, but nothing would work. Doctor finally prescribed Singulair, and I have had relief ever since. The only problem is the medicine can make me very irritable to the point that my wife cannot stand me, and sometimes Singulair can cause insomnia."

• Mom...
• October 13, 2010

Montelukast for Asthma "My son has had asthma from the beginning, he was placed on Singulair at 18 months. It did seem to help, but he has now developed side effects, and we have taken him off of it. He becomes very agitated and aggressive. He is normally a very calm and sweet child. It took a while to put two and two together. We took him off, and his sweet nature came back. Truthfully, it scared me how much this medicine affected his mood. It works great for asthma, but we won't use it anymore."

• Anonymous
• September 4, 2015

For Allergic Rhinitis "I have been taking Montelukast for about 5 years. It's helped me considerably with my extremely severe urticaria. It basically stopped the symptoms completely. Since my condition was so extreme, I ignored the side effects of the drug for a long time. I have insomnia. I wake up every 2 hours, and I have mad dreams. I've always been a big dreamer, but since being under the influence of Montelukast, all dreams are basically nightmares. I'm extremely agitated during the day. Everyone basically annoys me. It's a bit rough, but I have it under control. I get a low fever randomly and quite heavy night sweats, too. I have now stopped taking it to see if my condition has improved so I can maybe sleep through the night again. Fingers crossed."

• des...
• Taken for less than 1 month
• December 19, 2015

For Asthma, Maintenance "My GP prescribed it for my 5-year-old daughter to prevent further attacks of asthma with the hope to reduce or stop Fluticasone inhaler as she takes high doses of it, but thanks to heaven we have Fluticasone. Just a few days after Montelukast, she became a totally different person with episodes of agitation, rolling in bed for 1 to 2 hours before sleeping, aggressive episodes hitting her little brother, which she has never done before this medicine, waking at least 3 times in the middle of the night shouting at me to come and be with her because she is afraid, and she told me that she feels unhappy with tearful eyes and she doesn't know why. I had to stop it just after two weeks, and she started to return to her normality."

• Ddr...
• Taken for less than 1 month
• October 15, 2018

For Asthma "I went on montelukast three weeks ago. I have had no prior mental difficulties, anxiety, or depression. Three weeks later, I’m experiencing agitation, anxiety, nightmares (which I haven’t had since I was a child). I’m a 52-year-old woman. I’m irritated, and my thoughts race. As far as those racing thoughts... I seem to get obsessed on a subject, and I can’t stop googling, looking, checking, and doing something related to that topic! Every day it’s something new to obsess over. A close friend who is a psychologist looked at the side effects of montelukast and said CALL YOUR DOCTOR. NOW. She also gave me the phone number of a psychiatrist. I called both my pulmonologist who prescribed and the psychologist. Ugh. This stuff works wonderfully, but quite seriously, I’d rather just cough and have asthma attacks."

• Ddr...
• Taken for less than 1 month
• October 15, 2018

For Asthma "I went on montelukast three weeks ago. I have had no prior mental difficulties, anxiety, or depression. Three weeks later, I’m experiencing agitation, anxiety, nightmares (which I haven’t had since I was a child). I’m a 52-year-old woman. I’m irritated, and my thoughts race. As far as those racing thoughts... I seem to get obsessed on a subject, and I can’t stop googling, looking, checking, and doing something related to that topic! Every day it’s something new to obsess over. A close friend who is a psychologist looked at the side effects of montelukast and said CALL YOUR DOCTOR. NOW. She also gave me the phone number of a psychiatrist. I called both my pulmonologist who prescribed and the psychologist. Ugh. This stuff works wonderfully, but quite seriously, I’d rather just cough and have asthma attacks."

• jba...
• Taken for 1 to 2 years
• July 1, 2019

For Asthma "My daughter is 4 years old and developed these behaviors over the course of 18 months. We were not informed about any of these side effects, and no monitoring was done either. Extreme fear, eczema, vivid nightmares, extreme fear of sleeping, facial infections, sleep disturbance, bedwetting, burning genitals and eyes, anxiety, depression, aggression/hostility, attention problems, bad dreams, hallucinations, hearing voices, irritability, memory problems, headaches, sore throat, cough, stomach pain, skin infections, runny nose, itching genitals, confusional state, crying inconsolable, difficulty concentrating, difficulty drawing, intentional self-harm, irrational fear of the dark, growling and hissing. We assumed all this was normal behavior for our, at the time, 2-3-year-old daughter. I wouldn't recommend this drug at all without proper monitoring."

• Su_...
• December 26, 2016

For Asthma, Maintenance "I have been suffering from asthma since the age of 7, and I was recently prescribed montelukast sodium after a bad chest infection, which had me hospitalized. I have taken it previously about two years back as well. However, since I began taking it this time, I noticed I can't fall asleep, I'm badly constipated, and extremely lethargic, depressed, irritable, and get angered really quick. No medicine is worth feeling this way, and I'm stopping this immediately. If a simple drug manifests such tangible changes in your body, imagine what it does to your body silently."

• Bre...
• July 12, 2015

For Asthma "Thought this med was my answer! I have severe allergies, which I am congested all day and makes it hard to sleep at night. This med cleared me up and helped me sleep at night. But by the 2nd refill, I became irritable, emotional, and so moody! I snapped at people and started having freaky dreams! I took myself off of it even though it worked for the allergies, it wasn't worth it! When I saw my doc and told her, she shook her head and said, 'that's odd, I never heard of it doing that,' but what I read here validates my experiences! Still can't find anything that works the way it did for my allergies!"

• Hid...
• Taken for 1 to 2 years
• May 26, 2023

Montelukast for Asthma "I was on this for a year with no improvement in my asthma. Two days after getting off of it, I began to have horrific withdrawals, including severe headaches, exhaustion, irritability, weepiness, depression, lightning shocks throughout my body, severe body aches, and inability to sleep. The worst seems to have occurred for 48 hours straight, with no signs of fever or sore throat to indicate flu. After seeing others in forums, it seems to be this medication."

• I...
• June 14, 2017

For Asthma, Maintenance "I'm a 19 y/o, and I've been on this medication for almost 2 months now. Since I've taken it, I have extreme nightmares and weird sleeping patterns. All this time, I've thought that it was helping me, but in reality, it has broken my life into pieces. I can't sleep on a normal pattern and have a lack of sleep, which has caused me to become irritable and not have a clear train of thought. If yourself or anyone you know is taking this medication, PLEASE monitor their behavior and sleep pattern."

• Ton...
• April 30, 2018

For Asthma "DO NOT USE SINGULAIR IF YOU HAVE HAD PAST PROBLEMS WITH DEPRESSION OR ANXIETY. Here's my story. I was put on Singulair when younger, so I decided to ask my GP to put me on it again (22 now). It helped with my asthma a lot, but I had to stop after 2 weeks as I was getting bad dreams and had heard that to be a side effect. So I went back on the inhaler and decided to only use Singulair when doing vigorous activities. I took one yesterday, and the dreams came back, and I also woke up today in a bad mood. I decided to take another pill today to keep the asthma under control while working, and within an hour I was easily irritated, depressed, and anxious. This continued, and these emotions amplified until I was extremely angry. At the time, I didn't know what was going on, so I got even more emotional and ended in a dark downward spiral. I've dealt with depression in the past, so I just assumed it was 'one of those days.' It wasn't until I googled Singulair and mood that I realized it was the Singulair."