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Originally Posted by http://www.eric.vcu.edu/inm/Mire.pdf
Ritalin-Induced Serotonin Syndrome: Overstimulating the Depressed Elderly
Ryan D. Mire, MD
A 72 year old man with a long history of severe depression, chronic obstructive
pulmonary disease, cerebral vascular accident, and hypertension was admitted
to the hospital for dehydration and anorexia. His antidepressant outpatient
medications were paroxetine and trazodone. An extensive workup for failure to
thrive was ultimately negative and his presentation was felt to be secondary to
long-standing, severe depression. Methylphenidate (Ritalin) 5 mg qd was added;
after several days without any improvement, the dose was increased to 5 mg bid.
Soon thereafter developed tachycardia, tachypnea, and fever. Upon transfer to
the intensive care unit, vital signs were temperature 105.20F (rectally), blood
pressure 170/63 mmHg and heart rate 145 beats/minute. Physical exam
revealed lethargy, diaphoresis, mydriasis, wheezing, severe rigidity, hyperreflexia
(4+), and sustained clonus. Laboratory studies revealed rhabdomyolysis,
leukocytosis with left shift, azotemia, and metabolic acidosis. He was intubated
and treated with external cooling, broad-spectrum antibiotics, and midazolam.
Head computed tomography, lumbar puncture, and electroencephalogram were
negative. Although his course was complicated by myocardial infarction and
Citrobacter bloodstream infection, he improved significantly after 72 hours and
his antidepressants were changed to bupropion.
Serotonin syndrome is a diagnosis of exclusion manifested by a classic triad of
abnormal cognitive/behavioral changes, autonomic instability, and
neuromuscular changes. It has increased in frequency since the introduction of
selective serotonin reuptake inhibitors (SSRIs). Symptom onset and intensity are
extremely variable. This patient had multiple potential etiologies for serotonin
syndrome, including paroxetine and trazadone, both of which increase serotonin
neurotransmission. Interestingly, amphetamines not only affect norepinephrine
and dopamine, but also increase serotonin availability in the synaptic space and
have been associated with serotonin syndrome. Methylphenidate, in particular,
can precipitate serotonin syndrome through a direct affect on increasing
serotonin and through the increase of dopamine. In this case, methylphenidate
was the precipitating cause as evidenced by the onset of symptoms with the
rapid increase in dosage. The laboratory findings in this case were non-specific
and consistent with cases reported in the literature. Although there is no
diagnostic laboratory test available, the clinical picture accurately meets the
clinical criteria for serotonin syndrome. Methylphenidate has been documented
as an adjunctive therapy for treatment-resistant depression; however, caution is
recommended in selecting medications to prevent this potentially fatal drug
interaction.
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29-12-2008, 01:34
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