Sedation is more common with medications that have histamine-blocking or alpha receptor blocking. Although, all SSRIs can cause sedation, the most sedating SSRIs are Luvox (fluvoxamine), Paroxetine (Paxil), and Citalopram (Celexa).
If possible, sedation may be best managed by adjusting the time of dosing to correspond with bedtime. Increasing daytime exercise can also be beneficial. If the SSRI is very effective, it may be worth adding a stimulating medication such as Wellbutrin, Provigil, or Strattera.
If dosing adjustments and augmentation are not beneficial, a switch to a non-sedating antidepressant may be necessary.