Weight gain!

[Bonnibelle]

I have been on mirtazapine for 4 months now. I have always been very underweight so to gain weight has been lovely, I am really enjoying the curves and nice comments from everyone :-) I was 6 stone 4lbs last year (I am only 5ft tall) and by May I had gone up to 7 stone, my appetite was quite good despite being agoraphobic and suffering from PTSD. Since being on Mirt I have gained 16lbs in 16 weeks. My GP today weighed me and said I am a good weight now and my BMI is perfect but he is concerned if this trend continues.

He wants me to watch what I am eating. I don't eat fatty fried meals but since being on Mirt I have liked the odd cake or two I am to cut cakes out and try to stick to low calorie snacks and meals. In 4 weeks he wants to weigh me again and if I have still gained weight then he said he will be concerned and we may have to look at me coming off the medication. I am only on 7.5mg. He said that it may just be the increase in calories and for the first time in my life I have to watch my weight or it could just be that Mirtazapine causes weight gain. Is this possible? Surely it will be due to increased calories? but I wouldn't say I am eating excessively at all.

A typical day for me is

Breakfast - Fruit smoothie and Strawberry oat crunch cereal.
Mid morning snack - Banana.
Lunch - Jacket potato or rice cakes with philly cheese and a yoghurt.
Afternoon snack - Cereal bar. few times a week I may have a cream cake.
Dinner - Spag bol, tuna and salad, chips with chicken and salad.....
Supper - cake or ice cream but I would say only 3 nights a week.

So I don't eat alot. Some days maybe a bit more. I just hope I don't have to come off it as it has really helped me get over the PTSD and get me out again and I have won my Agoraphobia battle pretty much, I am doing so well.

[Mark13]

I've been on mirt for over 6 years, recently upped it to 30mg and I'm dieting and losing weight just fine. In fact I'm a lower weight now than when I started mirt in May 2007.

The drug does give you the munchies for a while, so you eat more, but it soon settles down. Unless you have a weight problem like me, then the munchies become more of a habit than an actual compulsion.

I'm not aware of any chemical reason why this drug would promote weight gain, it just increases your appetite.

So you just have to have a bit of self control, that's all, the "cravings" soon subside when you don't feed them

Good luck, hope it all goes well for you.

[hanshan]

Hi Pearl,

That could be a lot if you eat ever so little more, and mirtazapine changes your perception of how much you eat. I always tell myself that weight gain is just a sandwich a day away. The only way I have been able to lose and / or maintain weight while taking mirtazapine is to keep a list of everything I have eaten during the day (I do it now in a file on the computer, so I can copy and paste when I eat the same things) along with approximate calorie equivalents and add it all up each day. If I stop doing that, the weight starts going on, so it is calories for me.

On the good side, I just trimmed two inches off one of my belts, because it had gotten too long, and I've been punching extra holes!

[Bonnibelle]

Hopefully it is just calories. I haven't gained anything in the last week x

[hanshan]

Actually, I don't know exactly what it is that causes weight gain with mirtazapine (but neither does anyone else, at least scientists willing to bet their reputations).

That mirtazapine is associated with weight gain seems clear. I can't quote the study here (because I don't have it at my fingertips, but I could probably dredge it up, if anyone is interested), but a review of several academic studies found an average gain of (if memory serves me correctly) around a pound a week in the first few weeks of taking it. To me, that's a massive gain if continued over time.

There are various theories. One is that mirtazapine plays around with the normal hunger/satiation response to food. That is, we are either more hungry before or less satisfied after eating, or both. Another theory is the metabolism theory, that it slows the body's metabolism, so we need less food, but we still keep eating the same amount. There are even more complicated theories relating to changes in how certain food groups are processed by the body.

So what can you do? Just give in? I say no. It doesn't matter by what mechanism mirtazapine causes weight gain. There are only two ways to fight it. What we eat and how much we exercise. (But that's another post).