Weight gain through amitriptyline

Taking tricyclic antidepressants such as amitriptyline can lead to increased weight gain depending on the dose. This is one of the very common side effects, one in 10 patients is affected. The side effect often occurs at the beginning of taking amitriptyline and as a result many patients stop taking the drug early and thus act against the advice of their doctor.

Many depressives refuse to even try amitriptyline therapy before, because they are too afraid of the side effects. Both factors make the therapy of depression even more difficult and slow it down. Besides amitriptyline, there are other antidepressants that can be associated with weight gain: These include imipramine, clomipramine, doxepin and trimipramine; like amitriptyline, these drugs belong to the tricyclic antidepressants or NSMRIs (non-selective monoamine reuptake inhibitors).

Mirtazepine is also said to have a weight-increasing effect; the active substance belongs to the NaSSA (noradrenergic and specifically serotonergic antagonists). Amitriptyline spreads its antidepressive effect in different ways. Its main effect is to prevent the reuptake of the important messenger substances noradrenalin and serotonin after they have been released by nerve cells.

Among other things, it also influences histamine and serotonin receptors; these are inhibited. A resulting reduced release of histamine and serotonin can explain the weight-increasing effect of amitriptyline. Histamine is a central transmitter in the brain and is involved in the regulation of the day-night rhythm, heat regulation, the release of hormones via the pituitary gland, brain learning processes and food intake.

If histamine binds centrally (i.e. in the brain) to the H1 receptor, the body is signalled to be satiated and food intake stops. The same applies to serotonin: binding of serotonin to the receptor in the central nervous system leads to a reduction in appetite. If these receptors are inhibited by taking amitriptyline, this can lead to an increase in appetite and food intake.

In most cases an increase in weight is accompanied by an increased calorie intake. Those affected speak of attacks of ravenous hunger and the feeling of insatiable hunger. Sometimes, however, the increase in weight is only noticeable on the scales.

This can be remedied by avoiding high-calorie snacks and keeping a diet diary to keep daily calorie consumption under control. A suitable dietary measure can be discussed with your doctor. If these measures do not help to reduce weight, consideration should be given to switching therapy to another antidepressant.

Drugs with a different active profile have little effect on the organism in terms of weight gain and sometimes even weight reduction. Fluoxetine, sertraline, citalopram or venlafaxine are examples of such drugs. The first three drugs belong to the selective serotonin reuptake inhibitors (SSRI‘s), the clinically most relevant group of antidepressants besides the tricyclic antidepressants. Venlafaxine is one of the serotonin norepinephrine reuptake inhibitors, SNRIs for short.