Definition and serotonin
The serotonin syndrome is due to an exaggerated increase in the serotonin signal centrally, resulting from the hyper-stimulation of its receptors. This event can be caused by the abuse of one or more drugs and / or drugs that:
- they increase the synthesis of the hormone serotonin or its precursors
- they reduce degradation or reuptake
- they directly stimulate the receptors, called serotonergics.
What is serotonin?
At the enteric level, serotonin increases intestinal motility and stimulates vomiting; in blood vessels it promotes vasoconstriction, resulting in migraine, and platelet aggregation. Through the stimulation of the sensory endings, the serotonin causes pain and at the nervous level it interacts with different neurons stimulating some and inhibiting others.
Causes
The primary cause of the serotonergic syndrome is hyperstimulation of receptors that capture serotonin in the brain (5-HT1A and 5-HT2 receptors). This anomaly can be the consequence of inappropriate pharmacological use or individual hypersensitivity; more frequently, the serotonin syndrome correlates to the excessive dosage of a serotonergic drug or to the combination of two different but adjuvant drugs.
Among the molecules that, combined together, are able to determine the serotonin syndrome, we highlight above all:
- Serotonin precursors or serotonergic agonists (such as the amino acid tryptophan)
- Agents that increase serotonin release
- SSRI drugs (paroxetine, fluoxetine etc.)
- Non-selective serotonin replacement inhibitors (doxepin, clomipramine, imipramine, dextromethorphan, etc.)
- Non-specific inhibitors of serotonin metabolism (hypericum, MAO)
- Hypericum and hypericin
It is also possible that the serotonin syndrome is manifested by the action of a single pharmacological agent. This can probably be a precursor of serotonin (see above) or a molecule responsible for increasing endogenous release; in practice, among those that increase the endogenous release we remember the extasy, the amphetamines, the cocaine and many other amphetamino-like drugs.
Symptoms
To learn more: Symptoms Serotonin Syndrome
In most established clinical cases, the serotonin syndrome occurs on 3 fronts:
- mental and behavioral changes
- autonomic dysfunctions
- motor alterations
More specifically, the serotonin syndrome is characterized by:
- Abdominal pain
- Diarrhea
- Hot flashes
- Hyperthermia (increase in body temperature)
- Sweating
- Lethargy (continuous sleep)
- Sudden changes in the state of consciousness
- Tremor
- Rhabdomyolysis (muscle cell injury / rupture)
- Kidney failure
- Shock (cardiovascular event that determines the insufficiency of blood supply to the tissues)
- Possible death!
However, only three of the following primary symptoms are sufficient in the clinical diagnosis of serotonergic syndrome: altered mental status, myoclonus (short and involuntary muscle contractions), agitation, hyperreflexia (excessive vivacity of reflexes), chills, tremors, ataxia (progressive loss of muscle coordination), diarrhea and fever. It is also fundamental that the differential diagnosis be carried out from infections, intoxications or metabolic alterations.
NB . In 75% of cases, the symptomatology of serotonin syndrome emerges 24 hours after ingestion or overdose; in the less important cases it is possible to wait 24-72 hours for the spontaneous resolution of the symptoms, while in the more serious ones the pharmacological intervention becomes indispensable.
Bibliography:
- Guidelines for the treatment of psychiatric disorders - M. Clerici, C. Mencacci, S. Scarone - Masson - pag 626
- Phytopharmacovigilance: Supervision on the Safety of Phytotherapeutic Products - F. Capasso, F. Borrelli, S. Castaldo, G. Grandolini - Springer - page 115
- Therapies of Neurological Diseases - A. Sghirlanzoni - Springer - pag 611
- Signs and symptoms of emergency medicine - SR Votey, MA Davis - Elsevier Masson - pag. 154-155
