How long will it take to feel the effects of strattera (atomoxetine)? Is it fast acting?

Not a stimulant. Strattera (atomoxetine) definitely not fast acting, often taking several weeks to affects adhd symptoms. It must be taken daily, and the dose may need to be raised slowly to minimize se. However, when it does work, it provides 24-hour coverage of adhd symptoms and benefits can continue to build for 6 weeks or longer. Sadly, it does not work as often as stimulants; but, when it does, it can be a real boon.
Strattera (atomoxetine) Agree with my colleague, but add that with gradual increasing of dosage as detailed in the strattera (atomoxetine) pamphlet schedule, noticeable effects are seen after 4-5 weeks of starting the low dose.