Serotonin has become a household word, thanks to Prozac (fluoxetine). Millions of people take this popular antidepressant or related drugs such as Zoloft (sertraline) and Paxil (paroxetine) every day.
These medications are known scientifically as SSRIs: selective serotonin reuptake inhibitors. They work by allowing serotonin to accumulate between nerve endings. This brain chemical helps to regulate mood and appears to be important for sleep, learning, appetite, sexual behavior, pain, perception and movement.
But although serotonin is essential for good health, it has a darker side. Too much serotonin can cause bizarre behavior, and some people taking these medications may be at risk of life-threatening drug interactions.
Serotonin syndrome can cause a range of problems, from anxiety, agitation and muscle twitches to nausea, sweating, confusion, convulsions and even coma. This condition may be triggered by some common combinations. One person wrote:

“As a Prozac user, I had bad reactions to cold medications in the past. I don’t know which ingredients caused the negative effects (mental disconnection, dizziness, nausea) so I mostly stayed away from them.
“But after four days of sinus congestion and being on call for some important work, I recently tried one Dayquil Liquicap. I had no problems, so I tried another in the afternoon and a third before bed. My head cold improved greatly, but the next morning I had a horrible reaction.
“I felt disconnected and jittery. I was confused and had difficulty running my daughter’s birthday party. I felt like I was going through the motions from a distant place, and watching myself do this made me even more nervous. Later I felt dizzy and had to lie down. I also was nauseated and ended up with a terrible headache.
“My doctor says Prozac could not account for these symptoms. But I am convinced at least part of my reaction was physiological. Is there an interaction between Prozac and any of these ingredients: pseudoephedrine, acetaminophen, dextromethorphan?”

The combination of Prozac and the OTC cough suppressant dextromethorphan could have triggered her unpleasant symptoms.
Other interactions are potentially more dangerous:

“My son was taking Xanax (alprazolam), Neurontin (gabapentin) and Zoloft (sertraline) for anxiety and depression. On February 4, the physician who was prescribing these medications also prescribed Imitrex (sumatriptan) for a headache. On February 9, my son had two strokes, went into a coma, and was declared brain-dead. He died on February 18.
“Before this tragedy he was in very good physical condition at 53 years old, with no history of heart or vascular disease. Four doctors involved in his care called the case bizarre and had never seen anything like this before.
“I have been told that Imitrex should not have been prescribed for a patient who was taking Zoloft.”

This grieving mother is correct. The migraine medicine Imitrex should not be combined with sertraline, fluoxetine or similar antidepressants because of the risk of serotonin syndrome.
We lost someone very dear to us from a serotonin syndrome adverse reaction. Joe’s mother Helen was in the hospital for angioplasty of one coronary artery. Even though the medical staff had been warned that Helen could not tolerate narcotic drugs of any kind, a resident injected Demerol (meperidine) into her intravenous line while she was sleeping. It interacted with another medication she had been taking (selegiline). The resulting muscle contractions caused severe thrashing about for hours. The nurses tried tying her legs to the foot of the bed to keep her still after angioplasty. Helen died the next morning from a hemorrhage and a fall on the way to the bathroom.
The bottom line is that patients must be extremely vigilant to avoid these kinds of life-threatening combinations. To protect yourself and those you love we suggest reading our chapter titled “Drug Interactions Can Be Deadly” in our book Top Screw-Ups Doctors Make and How to Avoid Them. You will also learn about the most dangerous drugs in the drugstore and what to do before filling and accepting a prescription from a pharmacy.
Antidepressants such as Wellbutrin (bupropion), Celexa (citalopram), Pristiq (desvenlafaxine), Cymbalta (duloxetine), Lexapro (escitalopram), Prozac (fluoxetine), Serzone (nefazodone), Paxil (paroxetine), Zoloft (sertraline), and Effexor (venlafaxine) can be helpful. But people taking such drugs must be informed about potential interactions so they will know what dangerous mixes to avoid. Do not assume your doctor or pharmacist will check out every combination for safety. You are your own best advocate. Here are some tools to help you in that quest.

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  1. BrianW

    I’ve been living with severe Rheumatoid Arthritis for about 30 years now. I also suffer from anxiety or depression so I’ve been taking Citalopram 20mg once a day. For the last 5 years I’ve been unusually sick with symptoms of…
    forgetfulness (at night I actually couldn’t remember what I did in the day)
    overheating and sweating (especially at night)
    fluctuating high blood pressure
    leg spasms
    tendons in the legs pulling
    severe fatigue
    feeling like I’m not present
    a dry itchy (metallic tasting) hack (cough) that won’t go away
    blacking out when I laugh too hard
    sinus problems

    Since my doctor put me on high blood pressure medicine I thought that was the reason for most of these side effects so we spent about 4 years trying to find one I could tolerate.
    Since he’s had no problems with other patients on HBP medicine he thought these symptoms were all in my mind.

    Anyways, up here in Canada drug interactions have been in the news lately as an elderly woman died from two medications that are lethal when used together.
    The doctor blamed the pharmacist and the pharmacist blamed the doctor for this major blunder.

    Since the report there’s been kind of an “awakening” of some pharmacists and I guess mine was one as I’ve been taking Citalopram along with a anti-nausea pill for about 8 years and only recently got the warning the two can cause Serotonin Syndrome.
    I looked up the symptoms and DAMN!.. a lot on my list above are there!

    So I immediately stopped the anti-nausea pill and saw my Doc.
    He dismissed my findings (as he usually does) but “humored” me with letting me come off the Antidepressant at my request.
    So after a month of being off both drugs my dizziness and vision cleared and I stopped my all-night hacking. (it was my brother who pointed out I was no longer coughing)

    However shortly after I was off the antidepressant I was having mood swings and nightmares.
    Well after an argument with the Doc on one visit he recommended I go back on Citalopram to which I did because I missed its benefits.
    I actually felt better at first because withdrawing from Citalopram gave me severe upset stomach/diarrhea and triggered a painful flareup with my Arthritis.
    But after about a month of being back on it the hacking and most if not all the symptoms above came back so I stopped the Citalopram recently again to which my Doc doesn’t know yet.

    The side-effects haven’t gone away yet (it’s been about 3 weeks since I last stopped)
    But now something strange happens when I take just one regular Tylenol
    (It actually happens every-time I’ve taken it for the past few years)

    The persistent, dry, keep me up all night hacking is back.
    The extreme fatigue is back.
    My internal clock doesn’t seem to work as there’s no point in the day I feel awake and have to nap about every fourth hour. (it’s 9:pm right now and I have to lay down now only to get back up around 11:00pm)
    I get sores on my gums
    My left eye is wateryagain
    In short I have basically most of the symptoms above from ONE Tylenol I took 5 days ago.

    So I googled “Tylenol and Serotonin Syndrome” tonight and found this site.
    Now I’m wondering if I should see a toxicologist.
    I can already hear my doctor dismissing my concerns so I’m thinking how I could go about getting a recommendation from him or someone else?

    Someone posted this above and… boy…do I relate.
    “I now have: chronic sinusitis, pressure behind eyes, runny eyes, emptiness, confusion, forgetfulness, tired all the time, lose interest easily, say inappropriate words, obsess,
    over all I do not feel well, I feel like I am living in a fog and can’t find my way out
    Also weight gain”

  2. Mark

    Well, this article is a little bit ridiculous. The writer is taking some of the most extreme situations and possibilities and making it as if death or near death experiences are a sure thing. I am currently on Prozac 40mg, Lamictal 200mg, Klonopin 2x Daily .125mg, and have absolutely no issues with cold medicines whatsoever. Although I agree there is always the possibility of having issues with the combinations of these medicines, this goes for all medications. It all depends on the individual themselves as well as the dosage, which neither specifics were shared in this article. Quite unfortunate to see such articles as this flood the internet these days. I merely suggest that those who believe drug interactions may be dangerous or even fatal, to take their time and at least attempt finding scholarly articles or concrete proof before making rash conclusions. Just a thought!

  3. Betty P.

    Just trying to stay alive, with your help

  4. Cindy
    ontario canada

    I have been suffering with major depression for some time now. I believe I suffer from Borderline Personality Disorder. There is a shortage of Psychiatric help in the area where I live. I have been taking 150 mg of Zoloft daily. The only way I can take it without having severe pain or feeling sick, is to eat yogurt before and after.
    The very first night taking Zoloft 50 mg, my head felt like it was going to explode, the pain was so bad, I was afraid I was going to die.
    At the time I was seriously depressed, cried day and night, with total fear of doom.

    Since then, I don’t cry or feel a sense of doom.
    I now have: chronic sinusitis, pressure behind eyes, runny eyes, emptiness, confusion, forgetfulness, tired all the time, loose interest easily, say inappropriate words, obsess,
    over all I do not feel well, I feel like I am living in a fog and can’t find my way out

    Also weight gain

  5. Lori
    Denver, CO

    I started taking prozac approx. 3 mos. ago for an anxiety preventative. I already take xanax for alot of anxiety and 2 inhalers for breathing condition, I quit smoking this past January and I have almost 7 yrs. Clean and sober. I feel tired alot of the time, confused, I forget words, names, I get angry over stupid things and sometimes I just have bad thoughts. What does anyone think ? Thank you for your help.

    • Mark

      I have had similar issues in the past. I suggest trying out different benzodiazapines, if that is what works for you. In place of Xanax, I suggest Klonopin. I have been taking it for a couple of months now, and it does the trick even with taking the lowest dosage. I use the wafers, which act within 10 minutes of consumption, roughly 3-4 times as fast as Xanax. They also have a much faster half-life, meaning the effects will stay in your system several hours longer than Xanax.

      Regarding Prozac, I suggest staying on this drug and trying different shorter acting anxiety medications such as Klonopin before resorting to different types of longer acting medications such as this one. Good luck!


  6. D.M

    I was prescribed Imitrex and decided against it when I read the side effects. What I cannot find out is IF Imitrex is in the antidepressant family OR better said, if you are allergic to antidepressants, can you take Imitrex?
    Thanks so much.

  7. as

    Can you take lexapro at the same time as Zoloft without experiencing negative side effects or ss?

  8. T

    I took zoloft and imitrex well the generics for both together and almost died.
    People’s Pharmacy response: This is a very dangerous combination that could trigger serotonin syndrome. It can be life threatening.

  9. KJ

    I have been on Luvox and it has helped with OCD and depression. I am on a low dose if Vyvanse which has helped tremendously with ADHD and concentration. My job became nearly unbearably stressful and my blood pressure would go up with the increased stress at work. I have been on Altace and a atenolol for years but my psychiatrist put me on an anti-anxiety drug, Tranxene (a small dose). I had advised my doctor that I had seen to many people become addicted to Xanax and klonopin so he agreed. I have had migraines since the sixth grade and my family doctor put me on Imetrex. Although Imetrex takes care of the migraines, I don’t like taking it as I become terribly irritable after taking it.
    I just saw a neurologist who started me on Topamax. In a four week period, I only had one migraine, however, my cognitive skills disappeared. I could not add 2+2. I could not think of words. I took myself on the Topamax and, after reading about Serotonin syndrome, I am scared to death to take Imetrex! I am also on Asplendin–since the generic Wellbutrin did absolutely nothing and my insurance required me to take the worthless generic.
    With what I am on now, I have nausea and numbness in my feet and hands. I drop things constantly. However, my depression has improved in that I am not crying all the time. My doctor placed me on FMLA due to work-related high blood pressure (my blood pressure is fine at home where there is little stress), however, I am still worried about Seratonin Syndrome. At night, I take regular claritan and flonase for allergies. Do I need to have my meds re-evaluated?

  10. drisde

    My son was prescribed Zoloft. He had a convulsion at work 4 weeks after. He also took Xanax and Redbull the morning of his convulsion. We thought it was the combination of the 3 that caused the convulsion. However 2 years ago, another son also had a convulsion and lost consciousness while at the mall 4 weeks after taking Welbutrin.
    Our doctor said he never heard of anyone having a reaction to SSRI’s. SSRI’s are prescribed like candies as soon as the patient tells the physician he is depressed, could be for any reason..

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