Serotonergic syndrome: causes, symptoms and treatment

Excessive use of Antidepressant drugs can trigger this disorder.

Serotonin (5-HT) is a neurotransmitter produced by the body, and is necessary for the proper functioning of the body for a variety of reasons. is necessary for the proper functioning of the body for a number of reasons It is responsible for regulating certain physiological processes. But the excess of serotonin causes the Serotonergic Syndromea set of symptoms of varying severity that affects individuals who take antidepressants.

Its most common cause is overdose or interaction between drugs that have the ability to increase the release of serotonin.

In this article we explain extensively what functions serotonin is responsible for regulating:

• "Serotonin: the 6 effects of this hormone on your body and mind".

The importance of Serotonin for the body

Serotonin is a chemical substance with which neurons communicate, i.e., a neurotransmitter. neurotransmitter. It is synthesized from tryptophan, an essential amino acid provided by the diet because it is not manufactured by the body. Some foods containing tryptophan are: oats, wheat, almonds, eggs or oily fish.

But although many people think that serotonin is only found in the brain (acting as a neurotransmitter), the Central Nervous System (CNS) only contains 5% of 5-HT, as the small intestine produces the rest in the small intestine. the small intestine produces the restThis serotonin never reaches the brain, but has other functions in the body (e.g. it regulates the state of contraction of the smooth muscles of the blood vessels).

Although serotonergic neurons are present in smaller quantities in the brain, their functions in the CNS are very varied, since these neurons are highly branched and carry out a large number of synapses. Some of the most relevant functions of serotonin are: regulating appetite, regulating positive and negative moods, intervening in the filter of sensations (so it is related to concentration), controlling the level of body temperature, etc.

Serotonergic syndrome can be fatal.

The excess of serotonin stimulation on the postsynaptic receptors 5-HT1A and 5-HT2A at central and peripheral level has negative effects for the organism that can be can be very serious and even fatal.. The set of symptoms attributed to an excessive activity of serotonergic neurotransmission on these receptors is known as serotonergic syndrome, and was originally described by Oates in 1960.

In recent years the use of antidepressants has become very fashionable, and this is the main cause of the increase in cases of this syndrome. Antidepressants that inhibit serotonin reuptake are the treatment of choice for depression, anxiety disorders, generalized anxiety, obsessive-compulsive disorder, post-traumatic stress disorder, premenstrual diaphoretic disorder and bulimia nervosa.

Overdose or combination of these drugs can lead an individual to suffer from Serotonergic Syndrome, and since there are many drugs that can cause this condition, below are the most known pharmacological substances that are associated with Serotonergic Syndrome:

Psychiatric Drugs

• Heterocyclic antidepressantsHeterocyclic antidepressants : amitriptyline, imipramine, monoamine oxidase inhibitors (MAOIs)
• Selective serotonin reuptake inhibitors (SSRI)Selective serotonin reuptake inhibitors (SSRIs): citalopram, escitalopram, fluoxetine (prozac), paroxetine, sertraline.
• Selective dopamine and/or norepinephrine reuptake inhibitors (SSRI)bupropion, duloxetine, venlafaxine
• Mood stabilizerscarbamazepine, lithium

Neurological drugs

• Parkinsonian agentslevodopa, amantadine, bromocriptine
• Opioid agonistsmeperidine, fentanyl, hydrocodone, pentazocine
• AmphetaminesMethylphenidate, amphetamines
• Headache medicationsSumatriptan, eletriptan, rizatriptan
• Antiemeticsondansetron, granisetron, metoclopramide
• Antitussives :dextromethorphan

Other drugs

• AntibioticsAntibiotics: linezolid
• Drugs of abuse : cocaine, ecstasy, LSD
• Natural substances: hypericum, caffeine, l-tryptophan, ginseng
• Other anesthetics: tramadol

Symptoms of Serotonergic Syndrome

The symptoms of serotonin syndrome begin within hours of overdose or interaction between serotonin-enhancing drugs, and are characterized by what is known as a triad: autonomic, neuromuscular and neurological dysfunction. If it is not diagnosed in time and appropriate measures are not taken, serotonergic toxicity is associated with high mortality..

The characteristic symptoms are varied and can be mild or severe. The symptomatology of an individual with serotonin syndrome is shown below:

Treatment of serotonergic syndrome.

To treat the serotonin syndrome adequately it is necessary to have a updated pharmacological historyincluding over-the-counter medications or substances and phytopharmaceuticals.

Mild and moderate cases of serotonergic toxicity may resolve within 24 hours after discontinuation of drug treatment, but much depends on the half-life of the substances involved. Severe cases require immediate hospitalization and intensive care, as the patient may suffer severe hyperthermia, rhabdomyolysis or respiratory failure.

For treatment, even in mild cases, benzodiazepines are usually administered to reduce agitation, pseudoconvulsive movements and muscle rigidity. Proper hydration, control of autonomic instability or fever control is common as a supportive measure.

Cyproheptadine (Periactin), an H1 antagonist drug with activity on 5-HT2A in smooth muscle and with anticholinergic and antiserotonergic properties, is beneficial because it reverses the antidepressant effects, and a single dose can block approximately 85-95% of serotonergic receptors.

Bibliographic references:

• González A. R. (2009). The Serotonergic Syndrome. Medical Journal of the University of Costa Rica, 3(3): 16-30.
• Gillman P. Ken. (2006). A review of serotonin toxicity data: implications for the mechanisms of antidepressant drug action. Biol Psychiatry;59:1046-1051.