Mood altering drugs and the serotonin syndrome (Proceedings)
Aug 01, 2009
CVC IN KANSAS CITY PROCEEDINGS
Serotonin and serotonin syndrome
Early psychotropic drugs were non-selective and frequently targeted a variety of areas of the central nervous system (CNS) to exert their effect. Over time, it became apparent that certain neurotransmitters in the CNS were more influential in altering undesirable behaviors, and drugs that more selectively targeted those neurotransmitters were developed. Serotonin is one neurotransmitter that appears to be extremely important in managing these types of behaviors and older drugs that targeted a variety of neurotransmitters (e.g. tricyclic antidepressants) have, in human medicine, largely given way to drugs that more selectively alter CNS serotonin levels, including selective serotonin reuptake inhibitors (SSRIs) and non-selective serotonin reuptake inhibitors (NSSRIs).
Management of serotonin syndrome includes managing any severe CNS effects with diazepam or a phenothiazine; refractory seizures may require general anesthesia. Due to its serotonin-blocking effects, cyproheptadine (1.1. mg/kg PO or rectally q 6 hr prn) may be beneficial in managing the agitation, hyperthermia, and vocalization. Once animals have been stabilized and severe signs managed (or in asymptomatic animals), decontamination should be attempted. If the animal has not already vomited, induction of emesis or gastric lavage might be performed. Administration of activated charcoal is recommended in most cases, and is especially important if extended- or sustained-release products have been ingested. Severe tachycardia may be managed with beta-blockers such as propranolol (0.02 mg/kg slow IV, titrate up as needed). Fluid therapy is important to provide cardiovascular support and protect the kidney from hypotension-related injury. Acid/base status should be monitored and managed as needed. Serotonin syndrome resulting from ingestion of prompt release products generally lasts 12-18 hours; with extended- or sustained-release products, signs might persist up to 48-72 hours.