Posted by Sunnely on April 12, 2001, at 18:51:45
In reply to Effexor and dilated pupils, posted by AnneL on April 11, 2001, at 10:45:25
Hi AnneL,
Venlafaxine (Effexor) can cause dilatation of the pupils ("mydriasis") but the exact cause is obscure.
Mydriasis is commonly associated with the older antidepressants (tricyclic antidepressants) presumably because of their strong anticholinergic (muscarinic) effect. Even though Effexor does not bind to the muscarinic cholinergic receptors, it has both serotonin (5-HT) and norepinephrine (NE) enhancing effects. Serotonin agents have been reported to cause mydriasis, and raising NE levels might promote mydriasis.
The mydriatic effect of Effexor is not a major concern unless the person also has a form of glaucoma (narrow-angle) which can lead to increased in intraocular pressure and worsening of glaucoma. Slowly increasing the dose and/or reducing the dose of the medication usually avoids or alleviates the problem but the effect is usually transient and the pupils return to normal size in a few days.
Incidentally, FWIW, among the SSRIs (Prozac, Paxil, Zoloft, Luvox, Celexa), mydriasis appears to be more common with Paxil because of its both serotonergic and anticholinergic effects. For that matter, caution should be exercised when using Paxil (and Effexor) in the elderly.
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> My 13 year old daughter is currently hospitalized for depression and has been started on Effexor. Within 7 days she is now up to 112.5 mg. Ever since she started the Effexor, her pupils are huge! Is this normal? She is not on any other psychotropic drugs. I am also on Effexor at 75 mg. daily and did not a slight dilation in my pupils during the first week (thought they looked wierd), but they are back to normal. What causes this? Should I be concerned about my daughter's dilated pupils? Any thoughts? Thanks, AnneL
poster:Sunnely
thread:59419
URL: http://www.dr-bob.org/babble/20010411/msgs/59600.html