Compared to certain other plants, peace lilies don't need to be pruned very frequently. However, if, for whatever reason, one or more of your lily's limbs or leaves become brown or wilted, you may want to prune the leaves to keep the plant from wasting energy on the dying appendage.
Accutane is a retinoid, and not related to anti-biotics so the side effects are different. However, the list of potential rare side effects of accutane is long and includes headaches, nausea, muscle pain and depression.
You can see that caffeine also causes the brain's blood vessels to constrict, because it blocks adenosine's ability to open them up. This effect is why some headache medicines, like Anacin, contain caffeine -- if you have a vascular headache, the caffeine will close down the blood vessels and relieve it. With caffeine blocking the adenosine, you have increased neuron firing in the brain.