Aim: To compare the clinical features of venlafaxine and SSRI in self poisoning in presentations to the Emergency Department at Westmead Hospital, Australia.
Method: A retrospective study of all patients who presented with venlafaxine self poisoning compared with randomly selected patients with SSRI self poisoning to the Emergency Department between 1997 and 2006. Medical records of 36 patients who ingested venlafaxine were reviewed and 44 of SSRIs.
Results: Statistically significant differences between the two groups in clinical outcome measures included: patients with venlafaxine poisoning had a higher proportion of confusion (25% cf 0; p = 0), mydriasis (19.4% cf 2%; p < = 0.02). Serotonin toxicity was seen in 30.6% of patients with venlafaxine poisoning compared with 13.6% of SSRI poisoning (p = < 0.06). Patients with SSRI poisoning were associated with a significantly longer median QT on ECG than those with venlafaxine poisoning (372ms cf 346ms; p < = 0.03). However on further analysis with the QT Interval Nomogram, QT/HR results were not ‘at risk’ for either group. Statistically significant differences in the historical variables were: venlafaxine poisoning was associated with a higher degree of Toxicology referral (78% cf 41.9%; p < = 0.001), and more serious suicide intent (22.2% cf 4.7%; p < = 0.017). Major depressive disorder was diagnosed in 54% of venlafaxine self poisoners compared with 39% of SSRIs. One patient from the venlafaxine group died.
Conclusion: Venlafaxine poisoning was correlated with confusion, mydriasis, higher referral rates to a toxicologist and more serious suicide intent. This has implications for management of severely depressed and suicidal patients.
