Venlafaxine & Desmethylvenlafaxine

General Information

Venlafaxine is a phenethylamine derivative and reuptake inhibitor of serotonin and norepinephrine that has been used clinically since 1994 as an antidepressant. Daily adult doses are normally in the range of 75 - 225 mg being given in 2 - 3 portions for the normal-release form and in a single portion for the extended release form. 

Venlafaxine is known to undergo O- and N-demethylation. The O-desmethyl metabolite (measured in this assay) is believed to exhibit antidepressant activity similar to that of the parent drug, and it has a longer elimination half life.

Adverse effects resulting from Venlafaxine administration include nausea, vomiting, dizziness, nervousness, anxiety, tremor and blurred vision. Hepatitis has been reported after 2 months of therapy. Overdosage may cause hypertension or hypotension, cardiac arrhythmia, seizures and coma. Serotonin syndrome may occur if a patient receives venlafaxine alone or with other drugs such as trazodone or mirtazapine.