Posted by Sunnely on April 16, 2001, at 18:38:58
In reply to Weight gain and SSRIs, posted by Kathy99 on April 15, 2001, at 11:49:03
Hi Kathy,
SSRIs have similarity to the anorectic (appetite-suppressant) drug dexfenfluramine (Redux, now off the market) with regard to their serotonergic effect. Therefore, it would be expected that all SSRIs should exert a similar anorectic action and subsequent weight loss. However, case reports indicate evidence to the contrary. In addition, although the anorectic action of fluoxetine (Prozac) is well recognized, long-term follow-up studies in depressed patients and in obese nondepressed patients reveal that its weight-reducing effects are transient, even leading to a gain in body weight. Similarly, paroxetine (Paxil) and citalopram (Celexa) have also been associated with weight gain. These latter observations are unexpected because Paxil and Celexa are highly potent and selective SSRIs, respectively.
Although SSRIs are termed "selective serotonin reuptake inhibitor" drugs, they actually do not act purely and only on serotonin alone. It appears that the paradoxical weight gain observed with the SSRIs rest on the interaction of serotonin with multiple mechanisms. Aside from the serotonin receptors being involved, it appears other receptors play a role in SSRI-induced weight gain. These include histamine receptor (H1), dopamine (DA) receptors, and norepinephrine (NE) receptors. In addition, the role of glutamate, nitric oxide (NO), and leptins in SSRI action requires further clarification.
Finally, the neurobiology of depressive illness itself, and recovery from it, plays a major contributing factor to individual response to these drugs.
Bottom line is, the exact mechanism as to the SSRI-induced weight gain remains unclear.
Try to get hold of the reference cited below. I believe it will help you immensely with your lecture.
Reference: Harvey BH, Bouwer CD: Neuropharmacology of paradoxic weight gain with selective serotonin reuptake inhibitors. Clinical Neuropharmacology 2000;23(2):90-97.
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> I'm a bit confused by all the discussion of weight gain on SSRIs. It seems that many people attribute their weight gain to effects of the medication.
>
> Since it is well known that the only way to gain weight is to eat more calories than you burn, I wonder what is happening while SSRI users are GAINING weight.
>
> Is your appetite notably increased? Can you tell you are eating more than you used to?
> Do you choose fattier foods, nibble more?
>
> Is your exercise level notably reduced?
>
> Since there HAS to be a change in one of these, and pounds just don't accumulate without reason, I wonder if any of you remember the situation clearly or are going through it now.
>
> I'm interested because I'm taking SSRIs myself, and am also a nutritionist.
poster:Sunnely
thread:59947
URL: http://www.dr-bob.org/babble/20010411/msgs/60110.html