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Brain fog and exhaustion

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Hi everyone,

I'm new here, however have been suffering with depression since around the age of ten (I'm now forty).

I've been on medication all of my adult life, for depression. Past drugs have included Lustral (which left me feeling suicidal at worst and numb at best), Citalopram, Fluoxetine and Mirtazapine.

For the past four years I've been taking 150mg (slow release) per day of Venlafaxine.

In terms of depression, it's very good. I have some very low periods, but they're relatively short and my suicidal thoughts are nearly gone.

However the brain fog is now becoming unbearable. I can't focus on anything that takes more than may be three minutes. Even my vision and ears seem 'fogged' (I've had sight and hearing tests and they're fine). 

I have to nap for 30mins to an hour every day, due to terrible exhaustion, although my job isn't particularly mentally or physically taxing.

This is now ruining my life. I can't play with my young children as I have no mental energy whatsoever, so I live in a perpetual state of guilt.

I'm wondering if this is because of the Venlafaxine, or could this just be my mental state?

I'd be very grateful for anyone's thoughts on this. Because of previous bad experiences with anti-depressants, I don't want to go to the doctor to try something new unnecessarily. 
Thank you.


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Hi and welcome to the Forums, SeahorseSubmarine.

I am so sorry that you are struggling with debilitating brain fog and loss of energy as well as depression.  That is a whole lot to deal with. 

Since I do not have any personal experience with Venlafaxine, I am hoping that some of the members here who are on that medication will be able to offer something of use to you.

In the mean time, I hope you will make yourself at home here on the Forums.  I have had depression since I was 15 and am now 63.  Brain fog and lack of energy was something I experienced on an early antidepressant called Tofranil.   It was brutal.    Depression by itself is so brutal too.

Wishing you the best!  - epictetus


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Hi, I am 22 and have had depression since i was 11 years old and crippling anxiety for about 8 years now. About 3 months ago i started Venlafaxine and i have experienced what you are going through and im currently struggling with extreme fatigue even though my work isn't super demanding. The brain fog usually only lasts about a week and a half after having my dosages increased and for about a week after that is when i become SUPER tired thoughout the day. I wake up around 6:45 in the morning for work and around 2pm i get so tired that ive even passed out in my chair at work and have had co-workers wake me up. It is super emberrasing, job threating, and is just frustrating to have to deal with. I've tried drinking coffee or energy drinks (dont mix the two in the same day. not a good idea) later than i usually would have before getting on venlafaxine, to try to combat the fatigue when it normally comes around. The only way ive found that helps is if i'm constantly doing something. I plan on talking to my dr when i go back for my next appointment. Take care. x

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Welcome. While not on the same meds as you, I experience the brain fog and exhaustion too. I don't know how to tell if it's the meds (though I've been on the same for a long time) or the disease. I've also wondered if it's something unrelated to either. I keep meaning to go to my family doctor to for an exam, including blood work, to try to rule out any other causes. But I'm too tired and I don't have a lot of faith in my doctor. I do hope someone here can offer some advice. I just wanted to let you know that you're not alone. Best wishes.  

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I’ve been on same meds and dose as you are on and the tiredness/brain fog were early side affects for me and thankfully lifted by 4-6 weeks.  I wonder if your meds need adjusting?  Brain fog and exhaustion are awful, hope you feel clearer soon. 

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I used to feel this. I would get dizzy and would make mistakes in work and couldn't think straight. I had brain fog and everyone in work said I looked confused. 

The tablet at different doses effect different chemicals. When I was on 75mg and 150mg I remember the TV or PC monitor would make me feel dizzy like my eyes couldn't handle bright lights, or I was that drowsy I had to take a nap away from the computer and couldn't focus on a certain task for more than 30 mins. 

I went from 150mg to 225 and it has helped. I have trouble with memory and I have ED but the brain fog seems alot less.

try going to 225 or 300mg for a few month and see how it goes. 


If nothing changes or is worse when you have tried the higher dose then try a different tablet. 

Everyone is different and everyone wont get the same results from the same medication. 


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Hello there, 

Well, this definitly sucks.  Especially since I've been going through pretty much the same thing.  My dosage of venlafaxine has just been increased but for two years it has been slightly lower (112,5mg).  

I experience the brain fog and exhaustion.  I tend to sleep up to 14/15 hours a night and will wake up with what indeed feels like fog into my brain, not very much able to think or concentrate and my motivation is at a very low point.  

Grayson above has sugested caffeine or energy drinks, personnally I find I need to be more careful as they tend to increase my anxiety, don't know about you... in any case they are not usually a very long term solution and are not the best thing for your heart anyways.  

I've been talking to my doctor about this and he remarked that most of us with depression have a tendency to not move too much and he has advised sport.  Note that Grayson here also makes a very interesting point : he feels it goes away when he is constantly doing something, and in my opinion that goes in the same direction than my doctor's advice.  Activity, any activity does something, whatever it is to your brain and "wakes it up".  

I've been diagnosed with depression for seven years now, during which I went through some pretty intense stuff so obviously I'm not in my best mood and motivation is often hard to gather.  BUT, the days when I manage to muster the necessary motivation to exercise, I DO notice a difference in my state of awakeness and concentration.  I am not a neurologist obviously but I believe the release of (endorphines? adrenaline?) that is caused by physical activity probably acts like some sort of natural psychostimulant and will also cause your sleep quality to improve.  Also the more you manage to get yourself on the move the more you might feel motivated to do it again.  I believe depression is often made worse by staying sort of motionless... not that I'm more capable than others to escape it but I'm trying !  

The idea is to get your heart rate up a bit.  You might go for just a five, ten minutes run outside, or dance while tidying up, or even jog in one place while doing the dishes or watching TV.  I can't promise it's going to work for you but as I said it does help me when I can get myself to do it and obviously it can't do you harm to give it a shot ! :)
Finally, I understand you don't want to switch meds for no reason on first try, but it is NEVER useless to question your doctor about the effects of your medication and possible solutions.  Sometimes it's about dosage, sometimes another med might help.  I don't know how the health system works in your corner of the world, but here every pharmacist I've encountered was very helpful and nice so perhaps you could have a chat with yours about your issues !!

Best day to you ! xx :)


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The brain fog is likely a side-affect of Venlafaxine directly "increasing" your serotonin levels... SNRI's are theorized to work by slowing the reuptake of circulating serotonin (mainly) and also norepinephrine - in other words, the drug causes these neurochemicals to "pool" in your brain rather than "flow" betweeen neurons too quickly. Norepinephrine is an adrenalin-like compound, however Venlfaxine seems to only raise norepinephrine at doses of 225mg+

For doses of 150mg or less, serotonin will be more dominant, which can cause sleepiness itself (and also the complete opposite when in sharp bursts). The shift in balance will reduce the overall proportional balance of the other neurotransmitters, especially dopamine and acetylcholine. These are both stimulatory, assisting in memory formation, cognition and overall brain energy / functioning efficiency.

You can boost dopamine levels using the amino acids l-tyrosine and D,L-Phenylalanine (DLPA); from health food stores.

If you're prone to anxiety or psychosis, it might be best looking at boosting acetycholine instead. Eggs are high in choline, the other option is choline supplements - such as lecithin (sunflower oil or soya based like 'Lecigran') and CDP Choline. IANAD, however, amino acid intake has to be done in a measured fashion guided by results/symptoms and recommended dosages.

The other thing to consider is whether either/both of you taking the Instant Release (IR) or Extended Release (XR).

IR is a tablet, XR is a usually a bead-filled capsule.

Venlafaxine IR has a "half-life" (the time it takes for the peak concentration of the drug to be halved) of 5 hours (+/- 2 hrs), compared to XR (15 hours; +/- 6 hours). The attached graph shows the difference in the drug concentrations between the two verisons - IR peaks 6-7 hours after swallowing, XR is around 10 hours. IR drops off much sooner and quicker than XR (which is why IR is a pig to withdraw from). This sharp drop may explain your brain fog, especially if it happens consistently in the late afternoons.





Venflafaxine Dose Curves.png

Edited by Whostolemyfunny
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" I live in a perpetual state of guilt" first off my friend you need to get this dealt with by understanding that it is not your fault. Guilt just adds to the mental anguish of depression. Like you I was diagnosed with severe depression along with OCD and PTSD at a very young age of 12. You know, I'm sure, that depression does c cause severe exhaustion both mentally and physically. I read some on the medication you're on and it does look like the fog and visual disturbances are side effects. I've been on just about every antidepressant there is but I don't think this one. My only advice is maybe you need an add on to this medication such as Rexulti or the like. Just talk to your doctor about this. I was on Trintellix and after a while I was getting depressed and tired and was put on the Rexulti and it seemed to do the trick for me. I'm sure you love your children very much and I know there are things you can do with them that aren't really mentally exhausting or anything but just know your limitations and like I said be completely honest with your doctor and if he is a good one, then I'm sure something can be figured out. Remember guilt is something we all deal with but need to work on because it just makes things worse. Be good to yourself my friend...

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  • 1 month later...

I get the brain fog and lack of motivation too.  The lack of motivation was worse at a higher dose (225 mg) and now I am at 75 mg so the lack of motivation is a little better.  However, I can't go any lower or I get really upset about things.

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  • 2 weeks later...
  • 3 months later...

SeahorseSubmarine, how are you feeling now? Can you update us? 

I just quit my Effexor cold turkey about a week ago because I was experiencing the same things you mentioned plus some more side effects. Took me a while but i figured out that it’s because of the Effexor. I was always yawning 24/7 and had this awful craving for coffee to be more alert but it only increased my anxiety. I couldn’t sleep, constant pigged out (I think my brain was trying to offset the fatigue by eating), weight gain, AWFUL brain fog, slow reaction to everything etc etc. I can’t afford that because I’m in school full time double major and work full time as a flight attendant. I’m always on the move and having fatigue and brain fog is a huge no go. 

I do not recommend going cold turkey but I’m stubborn and although this past week has been hell from the withdrawal symptoms, I feel a lot of mental clarity. My psychiatrist is great but when it came to how I felt on Effexor, she kept dismissing me or trying to increase the dose. Or suggested exercise. I lift, and even that didn’t help! 

Hope you are doing better. Please update us if you can! 🙂 

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