What side effects may happen if my child goes on fluoxetine?

Varies. Generally, fluoxetine and like antidepressants (ssris) are well tolerated and have no worrisome effects on major body organs. They can cause trouble sleeping, produce agitation and restlessness, and induce mania in someone at risk. Also, rarely, for poorly understood reasons, they can cause suicidal thoughts and even attempts. All these effects are reversible if one decreases or stops the drug.