Posted by ed_uk on November 13, 2004, at 19:14:21
In reply to Re: ed_uk, posted by ed_uk on November 13, 2004, at 18:21:57
Look what I just found...
Question: I have a patient on sertraline who is experiencing memory problems. Is that likely?
Answer: Occasionally, the serotonergic antidepressants have been cited as causing reversible memory difficulties with extended use. Over 10 years ago, Apathy, inattention, and forgetfulness was accompanied by a decrease in frontal lobe functioning after long-term, high-dose fluoxetine treatment, normalizing after withdrawal. (Hoehn-Saric. J Clin Psych 1991) Although the enhancement of serotonin may alleviate anxiety, suicidality and depression, prolonged and excessive serotonin in the synapse may lead a decrease in transmission of dopamine in the frontal lobe. A decrease in dopamine transmission has been associated with a poor working memory and decreased attention span (Kapur S, et al. Biol Psychiatry. 1992;32:1-17).
How may an SSRI decrease the transmission of dopamine? To date, at least 15 different serotonin receptors have been identified; 5 of these receptors affect the transmission of dopamine (Ryan JM. Semin Clin Neuropsychiatry. 2000;5:238-249). Stimulation of the serotonin 2C autoreceptors on the presynaptic dopaminergic neurons in the frontal lobe may lead to a decrease in dopamine release. (Chaundry LB et al. Schizophrenia Res. 2002; 53:17-24). To use an analogy, these autoreceptors act as presynaptic "thermostats" detecting the serotonergic "heat" in the synapse, thereby affecting the firing of the of the dopaminergic "furnace". Stimulating these autoreceptors decrease the firing of the dopaminergic neuron, while blocking the receptors may increase the firing.
With those factors in mind, how may the memory disturbances occasionally associated with the SSRI's be reversed? Consider the following strategies:
1.Decrease the dosage of the SSRI and carefully monitor the patient for depression relapse; Hopefully, the depression will remain in remission while the memory improves
2.Change to a non-serotonergic antidepressant such as bupropion or nortriptyline. However, antidepressant efficacy may be compromised by NOT increasing serotonergic transmission
3.Add bupropion to the SSRI, since it may enhance dopaminergic functioning
4.Add a psychostimulant to the SSRI to enhance dopaminergic transmission
5.Add olanzapine to the SSRI, since olanzapine blocks serotonin 2C receptors and may enhance frontal lobe dopamine transmission (Zhang W, et al. Neuropsychopharmacology. 2000;23(3):250-262)
poster:ed_uk
thread:415568
URL: http://www.dr-bob.org/babble/20041113/msgs/415598.html