I would suggest asking your local pharmasist.

you may just be having difficulty falling asleep on the lexapro regardless, and the caffeine is just one more thing preventing you from falling asleep. how long have you been on the lexapro? i know when i switched from luvox (which does have interactions with caffeine) to lexapro (which i'm pretty sure doesn't) the 50 mg of seroquel i took for sleep didn't cut it anymore. i think it was because lexapro has a longer half-life, so it just never wore off and i never felt sleepy at night. that was the beginning of last year, but i've been off of an ssri for four months, and just stopped the seroquel two weeks ago - but i still have a really hard time falling asleep. it takes me till around 3 or 4 at night to fall asleep, and i sleep until eleven. so falling into a normal sleep pattern on or off the meds can be hard. you may need something else for sleep like seroquel. but if you can stand it, i would cut out the afternoon coffee and see if that helps any. i don't think there's anything special to lexapro when you drink coffee that makes you stay awake, but falling asleep on an ssri is tough regardless and an afternoon shot of caffeine is probably only going to make things worse. btw, you can order low cost generic Lexapro at licensed canadian pharmacy: http://pillca.com/item.php?id=3052