Serotonin Syndrome:
Many of these drugs act upon Serotonin or
5-hydroxytryptamine (5-HT) which is a neurotransmitter. It is found in
the gastrointestinal tract, in blood cells (platelets) and in the brain and
spinal cord (central nervous system). It is known to affect the feel of
well-being and happiness and can affect mood, appetite and sleep.
Serotonin has an effect on memory and learning. Serotonin is a
neurotransmitter that affects the brain and plays a role in aggression, pain,
sleep, appetite, anxiety, depression, migraine, and vomiting.
Several different classes of psychiatric drugs like anti-depressants,
anti-psychotics, anti-anxiety drugs, anti- migraine drugs and psychedelic drugs
affect the level of this neurotransmitter inside the neuro-synapses of the
brain. SSRIs act on the brain to raise levels of the neurotransmitter
serotonin without raising the levels of norepinephrine. This was thought to be
a benefit in treatment of depression, and later anxiety, panic, social phobia,
obsessive- compulsive disorder (OCD) , and many other conditions.
However when considering risk vs benefit of these drugs,
reasearch has shown that these SSRI drugs do not produce clinically significant
improvements in depression in patients who initially show moderate or even
severe depression. They show statistically significant but clinically
minor effects only in the most severely depressed patients.
Drugs such as tricyclic antidepressants (TCA’s) and
selective serotonin reuptake inhibitors (SSRIs) inhibit the reuptake of
serotonin, making it stay in the synapse longer. The benefits derived by
these drugs may decrease in selected patients after a long-term treatment.
Serotonin syndrome is a medical consequence of these kinds of psychiatric
drugs. Serotonin syndrome which can also be called serotonin toxicity is
really a poisoning and is the predictable consequence of excess serotonin
activity in the brain and elsewhere in the body which can be caused by
therapeutic use of these medications. No laboratory tests can currently
confirm the diagnosis and it is usually diagnosed base on the patient’s
symptoms and clinical history. Serotonin syndrome may be mistaken for a
viral illness, anxiety, neurological disorder, various kinds of poisonings, or
a worsening psychiatric condition. The Serotonin syndrome presents
characteristic clinical signs but can be mistaken for the more dangerous and
life threatening neuroleptic malignant syndrome. This presents as twitching,
tremors, rigidity, fever, confusion, or agitation.
Serotonin/norepinephrine reuptake inhibitors (SNRIs) also
may cause serotonin syndrome by interactions. Most tricyclic depressants do not
have these interactions, with the exception of amitriptyline.
The symptoms of Serotonin Syndrome are:
Cognitive effects: headache, agitation, hypomania, mental
confusion, hallucinations, coma
Autonomic effects: shivering, sweating, hyperthermia
(temperature as high as 104o F and even go as high as 106oF,
hypertension (high blood pressure), tachycardia, nausea, diarrhea.
Somatic effects: myoclonus (muscle twitching), hyperreflexia
(manifested by clonus), tremor.