SSRI: Types, Operation And Effects Of This Antidepressant
Of all the psychoactive drugs, serotonin reuptake inhibitors (SSRIs) are the most prescribed both in Spain and in most industrialized countries. This type of antidepressant is popular for several reasons: it is indicated for the most prevalent disorders such as major depression or anxiety disorders, they are effective and their side effects are almost always well tolerated.
If we understand why depression occurs, we can also understand How are SSRIs effective in treatment and through what mechanism do they act? We will do a brief review of how it works, what its properties and adverse effects are and in what disorders it is most frequently prescribed.
Although it may be cumbersome, it is necessary to understand how neurons work at the cellular level when they communicate with each other through neurotransmitters in order to understand how serotonin reuptake inhibitors modify neuronal activity.
Serotonin release and reuptake
When neurons communicate with each other, the presynaptic neuron (the transmitter of chemical substances that the other will receive) releases neurotransmitters into the synaptic space, which are picked up by receptors on the postsynaptic neuron In the case of the neurotransmitter circuits called serotonin, neurons use this neurotransmitter to communicate. One neuron releases serotonin into space and the other collects it, understanding that it must be activated.
What happens is that not all neurotransmitters are received and sometimes they remain floating in the intersynaptic space. There are pumps that are responsible for cleaning up this excess neurotransmitter and returning it to the presynaptic neuron.
In depression and other disorders, it is hypothesized that there is very little serotonin in this space, so that postsynaptic neurons, hungry for serotonin, create many receptors to receive neurotransmitters but are not activated and do not release anything, as in a state of hibernation. .
SSRIs block reuptake pumps and allow more and more serotonin to accumulate in space. The postsynaptic neurons, as they perceive that the concentration of serotonin in space is greater and there is more neurotransmitter available, begin to reduce the number of receptors because they no longer believe they need as many. The neuron relaxes its strict rule of not releasing anything, and begins to release serotonin and activate the rest of the neurons in the circuit.
Types of SSRIs
Not all SSRIs are the same. Each drug uses a different active ingredient that will have a specific therapeutic dose. Furthermore, as each active ingredient acts on different serotonin receptors , its side effects will also be different. It is this relationship between the efficacy, safety and tolerance of the drug that defines whether it is preferable to use one or the other.
Below you can see a list of the marketed SSRIs. In pharmacies we will find them under different commercial names depending on the country. For example, fluoxetine is more widely known as Prozac or escitalopram under the name Cipralex:
Safety, tolerance and side effects
In general, SSRI psychotropic drugs are safe Contrary to what happens with lithium salts, the toxic dose is difficult to achieve by mistake when we take SSRIs. Likewise, they do not produce the same tolerance as other drugs such as benzodiazepines, so it is not necessary to increase the dose due to the properties of the SSRI.
On the other hand, the side effects it produces are minor They can cause nausea, dry mouth, sweating, anorgasmia, decreased sexual desire and blurred vision, among other much less common ones. The abrupt cessation of SSRI consumption, although it does not cause addiction, can cause withdrawal symptoms, as the brain becomes accustomed to the presence of the substance. For this reason, the withdrawal of the drug is done gradually.
SSRIs They interact with many other medications , so close supervision by the prescribing psychiatrist is necessary. For example, there are some antidepressants that remain in the system for days or weeks after cessation of administration. When someone taking this type of antidepressant switches to an SSRI, the effects of the previous medication that has not yet been excreted and that of the SSRI may overlap. This causes the patient to suffer from serotonin syndrome, an excess of serotonin that causes a confusional state, agitation, headache, nausea, etc. and must be treated urgently.
Uses in psychiatry
Like tricyclic antidepressants, SSRIs are used for a wide variety of disorders. Naturally, the main use is in patients with major depressive episodes or depressive symptoms. The use of SSRIs It is very effective in ending depressive symptoms that can be found in patients with anxiety disorders, personality disorders, gender dysphoria, bulimia nervosa, autism, etc.
Since serotonin is also involved in anxiety, the benefit of SSRIs in anxiety disorders is often twofold. On the one hand, it calms the negative mood, and on the other, it reduces the experience of anxiety Especially in patients who experience chronic levels of anxiety such as generalized anxiety disorder, obsessive-compulsive disorder, post-traumatic stress or acute stress reactions, serotonin reuptake inhibitors will be very useful.
These patients, when taking SSRIs, experience a significant decrease in anxiety levels. This allows them to relax the worries and restlessness that torment them, recovering much of their quality of life and leading a functional life.
