Thanks for posting the query on XXXXXXX After going through your query, I would like to comment the following:
1. Normally laboratory tests are not indicated in cases of patients on venlafexin.
2. It is from SSRI
group of antidepressent medications.
3. Serotonin toxicity is one of the side effects of this drug though not so common and at present there is no lab test for its confirmation. It depends on the clinical symptoms which are based on presence of the following:
Spontaneous clonus, or
Inducible clonus plus agitation or diaphoresis
Ocular clonus plus agitation or diaphoresis, orTremor
Hypertonism plus temperature > 38 °C (100 °F) plus ocular clonus or inducible clonus.
4. If the clinical adverse effects are not developing then you are probably on a safe dose and physician has titrated your dose correctly.
5. In academic research direct serum levels of the drug are measured at tertiary care advanced laboratories but these are mostly for research purposes.The therapeutic plasma/serum concentration of venlafaxine
is approximately 0.2 mg/L.
6. Remember a golden rule in clinical medicine "treat the patint and not the reports". Thus if you have any symptoms then you need to report it to your doctor rather then trying to base treatment on mere investigations.
7. Also most of these neurotransmitter
changes occur in the CNS and can be picked up by functional scans at higher centers.
I hope I have answered your query. I will be glad to answer follow up queries if any.
Please accept my answer if you have no follow up queries.
Dr. Gyanshankar Mishra
MBBS MD DNB