In general, it takes 4 to 8 weeks to see an improvement in ADHD symptoms with Strattera. Some people see changes earlier, but the response is typically gradual and builds over time.

Strattera (atomoxetine) is a brand-name oral capsule. The Food and Drug Administration (FDA) has approved Strattera to treat attention deficit hyperactivity disorder (ADHD) in adults and children ages 6 years and older.

ADHD symptoms vary but can include:

  • inattention
  • difficulty following instructions
  • impulsive behavior
  • difficulty sitting or standing still

This article explores how long Strattera takes to work, its mechanism of action, and what to expect with continued treatment.

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Strattera starts to work after the first dose, but it takes time for ADHD symptoms to change. According to the National Alliance on Mental Illness, this is 4 to 8 weeks for most people. Strattera’s effects on ADHD are gradual and appear to build with continued treatment.

Study results

Strattera was shown to be effective for ADHD in clinical trials of 6, 8, or 9 weeks. However, many people taking Strattera notice that symptoms begin to improve within 4 weeks.

According to one study in a 2015 review, the median response to treatment in children ages 6 to 18 years was 23 days. This means that half the participants reported symptom improvement earlier than 23 days, and the other half reported improvement after 23 days. (“Response” is a clinical term for describing a person’s reaction to treatment.)

You may see anecdotal stories about Strattera working on the first day of treatment. However, clinical evidence reports responses within 1 to 2 weeks of starting Strattera. On the other end of the range, it may take 12 weeks (3 months) or longer to reach the full benefit of atomoxetine (Strattera’s active ingredient).

Part of the reason for the gradual and variable response is that it takes time to determine the right dosage of Strattera. (See below.) Also, the response to any drug varies from person to person.

How Strattera works for ADHD is not completely understood. Atomoxetine belongs to a class of drugs called selective norepinephrine reuptake inhibitors.

Atomoxetine is thought to work by increasing the levels of certain neurotransmitters (chemical messengers) in the brain. Specifically, the drug raises the levels of norepinephrine and, in certain parts of the brain, dopamine. This helps improve attention in people with ADHD.

If you’d like to know more about how Strattera works for ADHD, talk with your doctor.

Typically, doctors start by prescribing a low dose of Strattera and increase it over time. They may prescribe it as a single dose taken once per day in the morning or as equally divided doses twice per day. With divided doses, you’ll likely take half your daily dose in the morning and the other half in the late afternoon or early evening.

Strattera is effective for ADHD with either dosing schedule (once daily or divided doses). In fact, a clinical trial shows that once-daily Strattera in the morning has beneficial effects that last into the evening and the following morning. This may be because the neurotransmitter effect of Strattera can last up to 24 hours.

Are there benefits to taking Strattera at night?

It depends. A clinical trial comparing morning to evening dosing found that taking Strattera at night decreased ADHD symptoms. On some ADHD measures, morning dosing was more effective than evening dosing. However, taking Strattera at night may cause fewer side effects.

Since Strattera is not a stimulant medication for ADHD, you can take it in the evening. It may require a bit of trial and error to figure out what dosing schedule works best for you. It also depends on how Strattera makes you feel.

If you experience sedation or sleepiness from Strattera, taking the dose in the evening or closer to bedtime can be helpful. Also, if nighttime dosing works better for your schedule, it’s OK to take it at night.

If you have questions about the best time to take your dose, talk with your doctor or pharmacist.

Strattera is meant to be a long-term treatment to help manage ADHD symptoms.

An 8-month clinical trial found that symptoms continued to be well-managed during the full trial period. There were also fewer relapses in children taking Strattera compared with those taking placebo. (In the study, a relapse involved scoring higher on the ADHD rating scale used. A placebo is a treatment that contains no active ingredients.)

Talk with your doctor about how long you can expect to take Strattera.

Certain factors may affect how quickly Strattera works. For example, some people need to take a lower starting dose than is typically recommended. In these situations, it may take longer for ADHD symptoms to ease.

If you’re taking a lower starting dose and your ADHD symptoms don’t improve within 4 weeks, talk with your doctor. They’ll likely increase your dosage.

Before starting Strattera, your doctor will tell you whether you’ll need a lower starting dose.

Strattera is a brand-name medication prescribed to decrease symptoms of ADHD. Symptoms may improve within 2 weeks of starting the medication, but it usually takes 4 to 8 weeks for Strattera to work.

Experts don’t completely understand how Strattera works, but its effects seem to build with continued use.

You’ll likely have regular visits with your doctor when you start taking Strattera. They’ll monitor you during treatment to check whether the drug is working for your condition.

If you don’t see a decrease in your ADHD symptoms after 4 weeks, talk with your doctor. They can evaluate your situation and recommend next steps.