The neurochemical 5-HT (5-hydroxytryptamine) is a neurotransmitter called serotonin. It is a hormone found in the brain, pineal gland, blood platelets, and the gastrointestinal tract. It acts as a message carrier between nerve ends and also as vasoconstrictor. Serotonin is produced from L-tryptophan amino acid and its subtypes are found in many organ structures besides central nervous system. Certain cells in gastrointestinal tract contain about ninety percent of total serotonin availability. It occurs naturally in the body, in plants, and animal tissues and venoms.

As serotonin is scattered through out the central nervous system, it has the ability to affect various areas of brain that control and regulate psychological and biological activities of a person. In the brain, it is found in nerve centers that correspond to mood, thoughts, circadian rhythms, violent behavior, sexual behavior, appetite, etc. It influences a person’s mood and as a consequence, depression also.

Serotonin Syndrome – Causative Factors

It is a severe high serotonin condition. The syndrome results from extreme excitation of inner and peripheral serotonin based receptors. It is assumed to be associated with changes in responsiveness in serotonin receptor structures in the central nervous system due to ingestion of certain medications.

Generally, a person does not suffer serotonin syndrome by endogenous reasons alone. This syndrome is almost always caused by concurrent ingestions of serotonin-influencing drugs which cause serotonin levels to increase dangerously. Selective serotonin reuptake inhibitors (SSRIs) are examples of serotonin enhancers. These SSRIs, coupled either with monoamine oxidase inhibitors (MAOIs) or serotonin norepinephrine reuptake inhibitors (SNRIs), will cause serotonin levels to shoot up rapidly, causing a life-endangering situation.

The excess serotonin supply cause systolic blood pressure in a person to rise abruptly and it may cause strokes or cerebral hemorrhage. SSRIs, SNRIs and MAOIs are useful medications for treating depression in persons, as these medications cause serotonin levels in central nervous system to rise substantially. Serotonin syndrome can also occur in combination treatments with natural supplements like St. John’s wort.

It can also occur with overdose of depression medications.

The most popular drug that is known to most people is Prozac, which is a serotonin reuptake inhibitor drug. Treatment with the combination of Prozac with MAOI medications such as Desyral (tradozone), anafranil (clomipramine), etc., will contribute to sudden serotonin level increases and may prove fatal. The concurrent use of lithium and SSRIs will contribute to abrupt serotonin increase with disastrous consequences. The tricyclics, antidepressants, tryptophan, ECT (electric shock treatment), and fenfluramine (serotonin agonists) contribute to drastic increase in serotonergic activity. It is to be kept in mind that Prozac, Paxil, Zoloft, Luvox, Serzone, etc., are not to be used concurrently with each other or any other serotonergic drugs.

Diagnosis:

The diagnosis should include the knowledge of current medication usages for treatment of various mental illnesses or other illnesses. A correct investigation is necessary where an antipsychotic drug administration has commenced or dosage has been increased prior to the onset of serotonin symptoms. The onset may be within hours or it may take days. Diagnose whether the symptoms are related to: anticholinergic (acetylcholine receptor blocking) syndrome, lithium toxicity, infection of central nervous system, carbamazepine (anticonvulsant) toxicity, ethanol withdrawal, heat stroke, hypnotic/sedative withdrawal, opioid withdrawal, sympathomimetic overdose, etc.

Symptoms of Serotonin Syndrome:

The signs or symptoms of this syndrome may be combinations of some of the following:

Psychological changes that include irritability, nervousness, agitation, perplexity,

impatience, hypomania, hallucinations and coma.

Motor function changes include tremors, hyperreflexia, hypertonia, myoclonus, and

incoordination.

Autonomic changes include sweating, nausea, fever, emesis, diarrhea, and hypertension.

Life-endangering extreme complications include seizures, coma, rhabdomyolysis and disseminated intravascular coagulation (DIC).

Prevention and Treatment:

The simple thing to get relief from this syndrome is stop taking the problem medication. When people want to change medication, they are advised to wait for at least two weeks for the effects of previous medication to wear off. This is to avoid the effects of more than one medication in a patient at the same time. Prozac generally takes much time as its traces remain in the body for several weeks.

Alternative combination of medications needs to be explored to replace the original medications. Supportive care, along with altered medication should be explored to get rid of the symptoms of the syndrome. Some mild medications may be administered to provide relief from symptoms like muscle stiffness, diarrhea, fever, emesis, and hypertension etc.