Not being able to sleep (also called insomnia) is one of the most common side effects reported by people taking Cymbalta. In some people, this side effect improves after a couple of weeks of taking Cymbalta, but difficulty falling asleep or staying asleep can persist in others. Here are some ways you can improve sleep while taking Cymbalta:
Take your dose of Cymbalta in the morning. Cymbalta may be given once a day or twice a day but for those people experiencing insomnia, it should be taken just once a day in the morning
Swallow Cymbalta capsules whole; do not crush, chew, or open up the capsules and sprinkle them on food because this may cause Cymbalta to be absorbed more quickly than intended, increasing the risk of side effects such as insomnia...