In that respect, serotonin reuptake inhibitors (SRI) may be considered as a sub class of the antidepressant medication family. SRIs strive to increase the overall concentration of a neurotransmitter called serotonin in the brain. Today, SSRI, a specific class of SRI drugs has become the go-to drug for treating a number of mood based disorders.
SRI, SSRI and the relation between them
For the uninitiated, serotonin is a neurotransmitter (a naturally occurring chemical that conveys special instructions from one nerve cell and the other) that regulates a number of activities like sleep, mood, appetite, learning and memory. So, the chemical setup of an SRI drug is such that it increases the level of serotonin production within the brain and central nervous system when consumed in an ideal quantity.
Enhancement of serotonin levels happen to come naturally to SRI drugs. This is the reason why the term is interchangeably used with SSRI – the main class of drugs used for treating metal disorders like depression, anxiety, OCD etc. But, strictly speaking, there is a marked difference between the two.
For starters, SRI may either be selective in its serotonin enhancement action in which case it is referred to as Selective Serotonin Reuptake Inhibitor or SSRI, or it may be non-selective. A good example of non-selective SRI is cocaine, which not only raises the relative level of serotonin but also affects other neurotransmitters such as dopamine and norepinephrine. To avoid confusion, all further mentions of SRI in this article will mean SSRI unless mentioned otherwise.
Mechanism of action of SRI drugs
Just like any other neurotransmitter, Serotonin too is produced within the brain and after performing its intended function, it is reabsorbed in the brain. As such, SRIs primarily target this reuptake aspect of the neurotransmitter’s cycle and impede the chemical’s re-absorption process. Over time and with regular intake of the medication, a marked increase is seen in serotonin levels.
So, how does the medicine work as an antidepressant? Based on various studies, it was found that depression occurred mainly as a result of reduced serotonin activity in the brain. Thus, researchers predicted that if by some means a medicine could reinstate the neurotransmitter level to its optimal state, then the underlying symptoms of depression would automatically abate - hence, the use of Serotonin reuptake inhibitors.
Safety considerations when using SRIs
Even though SRIs are relatively safe to use, complications can arise if such antidepressants are taken without any consideration. For starters, SRIs are never a good idea if you are planning on having a baby. Taking drugs like Paxil during pregnancy may not only affect the unborn child but also disrupts milk production in the breasts in the later stages.
Then, there are drug interactions which may result in dangerous reactions within the body. For instance, SRIs taken with aspirins or anticoagulants may increase the risk of profuse bleeding from small cuts. So, if you are taking any other medication at the time of being prescribed SRIs, then make it a point to let your doctor know about your entire medical history so that he/she can make an informed decision on the best course of medication.