Trip Answers

Question answered:26/09/07 Warning! this question is over two years old.

We found a number of sources of incidence data, but it has been difficult to obtain figures for the UK.  In fact, of the references found, only one has reported basing the data on UK information.  However, we have tried to use sources that are UK-based.

 

Patient Plus (aimed at clinicians!) has a section on serotonin syndrome [1], reporting:

 

“Incidence is unclear due to the extent of under diagnosis.

 

Post-marketing surveillance studies on nefazodone suggest an incidence of 0.4 cases per 1000 patient-months of treatment.”

 

A 1999 article in the BJGP [2] was based in England and this also reported a “incidence = 0.4 cases per 1000 patient-months of treatment with nefazodone”

 

UK Medicines Information have also reported figures for serotonin syndrome [3], stating:

 

“…the incidence of the syndrome during SSRI monotherapy has been estimated to be in the range of 0.5 to 0.9 cases per 1,000 patient-months of treatment”

 

Patient Plus also has a section on Neuroleptic Malignant Syndrome [4], which reports:

 

“The exact incidence is difficult to calculate but is estimated to range from 0.02–2.4% with conventional antipsychotics, and a much lower incidence for atypical antipsychotics. A large Chinese randomised controlled trial showed an incidence of 0.12% of patients taking neuroleptics, and an Indian study gave a similar incidence of 0.14%.”

 

An American website, the Neuroleptic Malignant Syndrome Information Service, discusses incidence [5], stating:

 

“Although NMS is uncommon, the widespread use of neuroleptic drugs suggests that the absolute number of cases is not insignificant. Estimates of the incidence of NMS have varied depending on the population at risk, prescribing practices and methods of assessment. If data from published studies of NMS in patients treated with neuroleptics are combined, the incidence of NMS averages 0.2 percent.”

 

Finally, eMedicine has a chapter on NMS [5], reporting:

 

“Incidence is uncommon, with rates ranging from 0.02-12.2% of patients treated with a neuroleptic medication. Prospective studies and pooled data from the literature report an incidence of 0.07-0.2%. Because of increased awareness of this syndrome and efforts at prevention, the incidence is probably less now than in the past.”

 

References

1) http://www.patient.co.uk/showdoc/40024932
2) http://pmid.us/10818650
3) http://www.nelm.nhs.uk/Documents/QA48%203%20-%20Triptans%20and%20SSRIs.doc?id=547347
4) http://www.patient.co.uk/showdoc/40025090/
5) http://www.nmsis.org/general_information.shtml
6) http://www.emedicine.com/emerg/topic339.htm
 

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