Non-stimulant ADHD medication - atomoxetine and guanfacine

Most adults with ADHD respond well to stimulant medication, but a meaningful minority do not. Some patients cannot tolerate the side effect profile, others have co-existing conditions that make stimulants clinically inappropriate, and a few simply do not get useful benefit from either lisdexamfetamine or methylphenidate after proper titration.

For these patients the non-stimulant options in the UK are atomoxetine (Strattera) and guanfacine extended-release (Intuniv). Both are licensed and both can be effective. This article explains what they do, how they differ from stimulants, and when we use them.

Atomoxetine

Atomoxetine is a selective noradrenaline reuptake inhibitor. It is not a controlled drug, it does not produce the felt alertness that stimulants do, and it works through the noradrenaline pathway rather than dopamine. Unlike stimulants, which work within an hour of each dose, atomoxetine has to build up in your system over four to six weeks before its full effect is apparent.

The benefit profile is real but typically less dramatic than stimulants. Patients on a well-titrated dose of atomoxetine usually describe a quieter mind, less impulsivity, and improved task persistence, without the clear "it kicked in" moment that stimulants produce.

Starting dose for adults is 40mg daily for a week, then 80mg daily as the target dose. Some patients need 100mg. It can be taken once daily or split into morning and evening doses if the morning dose makes you sleepy, which is a common early side effect.

Common side effects: nausea and reduced appetite in the first two to four weeks (usually settles), tiredness, dry mouth, and occasionally low mood or irritability. A rare but important side effect is an increase in suicidal thinking, particularly in young adults, so we monitor mood carefully during the first twelve weeks.

Guanfacine extended-release

Guanfacine is an alpha-2A adrenergic agonist. It works through a different pathway again, stabilising prefrontal cortex function by modulating how neurons respond to noradrenaline. It is particularly useful for patients whose ADHD presentation has a strong emotional-regulation component or where anxiety sits alongside the inattention and impulsivity.

Starting dose is 1mg daily, titrated up by 1mg every week to a target dose of 4mg to 7mg daily depending on body weight and response. The titration is slower than for stimulants because the main side effect, sedation, is dose-related and builds gradually.

Common side effects: tiredness, low blood pressure, dizziness (particularly on standing), and dry mouth. The sedation often settles over two to four weeks but can persist enough to require a lower dose than optimal. Guanfacine is usually taken at night to let the sedation work in your favour rather than against you.

Guanfacine is officially licensed for children and adolescents in the UK. Its use in adults is off-label but is supported by clinical experience and a reasonable evidence base. We discuss this openly with patients when we are considering it.

When we use atomoxetine first

We reach for atomoxetine ahead of stimulants in specific situations.

You have a clear personal or family history that makes stimulants contraindicated. Cardiac history in particular, including a recent myocardial infarction, uncontrolled hypertension, or certain arrhythmias.

You have a history of amphetamine or methamphetamine use disorder.

You have tried both stimulants and either not responded or had significant side effects that limited the dose.

You have severe anxiety that has worsened on stimulants in the past.

You prefer a non-controlled-drug option for practical reasons (for example, frequent international travel to countries where stimulant prescriptions are hard to carry).

When we use guanfacine

Guanfacine is typically our third-line choice, used when stimulants and atomoxetine have both been insufficient or when the clinical picture has specific features that favour it.

You have ADHD with prominent emotional dysregulation, such as frequent intense frustration or anger.

You have anxiety or difficulty with sleep that guanfacine may help with as well as the ADHD.

You have not tolerated either stimulants or atomoxetine well.

Guanfacine is sometimes added alongside a stimulant rather than used as a sole treatment. This is more common in paediatric practice but we do use it in adults where a stimulant is doing most of the work but a residual piece of the presentation, particularly emotional reactivity or sleep, is not being touched.

What treatment with non-stimulants looks like

The main practical difference from stimulants is that non-stimulants need weeks to build up, so the titration timeline is slower and the sense of "is it working?" takes longer to resolve. We typically give atomoxetine six to eight weeks at target dose before concluding whether it is helping, and guanfacine four to six weeks at the top of the titration.

Monitoring is similar to stimulants: blood pressure, heart rate, weight, mood. The only real difference is that atomoxetine is not a controlled drug, so the shared-care process (if you move to NHS prescribing) is often easier and some GPs are more willing to accept it.

Honest summary

Non-stimulants are real medications with real effects. They do not work for everyone, but they work well for some patients whose lives would otherwise not be much helped. If a stimulant is not the right choice for you, you still have options.

Ready to start?

If this article has made you think it is time to find out, the next step is a short consultation with one of our ADHD-trained GPs.

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