Active ingredient: guanfacine hydrochloride · UK brands: Intuniv, Paxneury · Generic available
Guanfacine is a non-stimulant ADHD medication that works through alpha-2A receptors in the prefrontal cortex. Currently UK-licensed for ages 6 to 17, though off-label adult use occurs. Provides around-the-clock coverage and takes two to four weeks to reach full effect.
How guanfacine works in plain English.
Guanfacine works through alpha-2A adrenergic receptors in the prefrontal cortex, the brain region most involved in attention and impulse control. By stimulating these receptors, guanfacine improves the function of the prefrontal cortex without the dopamine-pathway action that stimulants rely on.
This different mechanism makes guanfacine an option for adults who cannot tolerate stimulants, who have co-occurring tic disorders or anxiety, or who have not responded to atomoxetine. It is not a stimulant and is not a controlled substance.
Like atomoxetine, guanfacine takes weeks to reach full therapeutic effect, typically two to four weeks. There is no daily peak-and-trough cycle. The medication provides 24-hour coverage from a single daily dose.
Food matters. Guanfacine should not be taken with a high-fat meal. High-fat foods can increase absorption by up to 75%, which causes higher peak blood levels and increases side-effect risk. Take it consistently with the same kind of meal, or consistently without food.
Guanfacine's close relations.
Other non-stimulant ADHD medications. Different mechanisms but a similar 'weeks-to-effect' framing.
Finding your dose.
Guanfacine titration typically starts at 1mg daily and increases by 1mg per week to a target dose. Maximum daily dose for adolescents is 7mg. Adult dosing is off-label and individualised.
Available doses: 1mg, 2mg, 3mg, 4mg.
Guanfacine is once daily, typically taken at the same time each day. Some prescribers prefer evening dosing because the medication can cause drowsiness initially. Take it consistently at the same time and with the same kind of meal pattern.
Guanfacine takes two to four weeks to reach full therapeutic effect. The first dose may produce drowsiness or dizziness, but the ADHD-related benefit takes weeks to emerge. Patient observation across this window is essential.
Avoid taking guanfacine with a high-fat meal. High-fat foods increase absorption by up to 75%, which raises peak blood levels and increases side-effect risk. Take it consistently with the same meal pattern.
ADHDose does not model a daily concentration curve for guanfacine because there isn't one to track. The app focuses on daily focus, sleep, mood, energy and side effects across the two-to-four-week titration window. The Clinician Summary export pulls that history into a structured PDF for your prescriber.
Steady-state coverage, tracked daily.
Guanfacine has no daily peak. What matters is daily metrics across the weeks it takes to reach steady state. ADHDose makes the logging structured and the patterns visible.
Guanfacine builds up gradually. Daily focus, sleep, mood and side-effect logging gives you and your prescriber the evidence you need to know whether it's working.
Every figure here is taken straight from the prescribing information, with the source on each row.
| Parameter | What the label states | Source |
|---|---|---|
| Active molecule | Guanfacine itself is the active alpha-2A agonist, not a prodrug | SmPC |
| Tmax | Approximately 5 hours (paediatric patients aged 6 to 17); single peak | SmPC |
| Half-life | Approximately 18 hours (parent guanfacine, not a metabolite) | SmPC |
| Food effect | In adults: high-fat meal raises Cmax by approximately 75% and AUC by approximately 40% | SmPC |
This SmPC covers only the licensed UK use, ADHD in children and adolescents aged 6 to 17; guanfacine prolonged-release is not licensed for adults in the UK, so no adult dose range exists to cite.
Not stated in the label: Duration of effect: the SmPC does not state a distinct clinical duration-of-effect figure for guanfacine prolonged-release, only the once-daily dosing regimen, so this row is omitted rather than estim.
Common side effects.
Most people tolerate Guanfacine well, especially after the first few weeks. Here are the patterns worth noticing, and the ones that warrant a call to your prescriber.
Do not stop guanfacine suddenly. Stopping abruptly can cause blood pressure to rebound above where it started, along with a rise in heart rate. Guanfacine is normally reduced gradually, by no more than 1 mg every three to seven days, with blood pressure and pulse checked as the dose comes down. If you want to come off it, or you have run out, speak to your prescriber or pharmacist rather than simply stopping.
Sedation and dizziness are the two most common reasons people struggle early on. Both are dose related and usually ease as your body adjusts. Logging them daily helps you and your prescriber judge whether they are settling or sticking.
Not emergencies, but worth bringing up. ADHDose tags recurring patterns automatically in your daily logs.
Guanfacine lowers blood pressure and heart rate by design, so fainting and a very slow pulse are the signs that matter most. Contact your prescriber rather than stopping on your own.
Titration, week by week.
The first weeks of Guanfacine have a recognisable shape. Knowing what is normal at each stage stops you reading too much into a single bad day.
Non-stimulants do not work like stimulants. The first dose does not produce a noticeable effect. The first week is mostly about managing initial side effects (mild nausea, fatigue, dry mouth) while your body adjusts.
Initial side effects typically settle by week two or three. Still no clinically meaningful effect on attention or impulse control yet; that is the nature of non-stimulants.
Most people start noticing real effect around the four-week mark, sometimes earlier with Qelbree, sometimes later with atomoxetine. The effect tends to feel less dramatic than stimulants and more like a gradual improvement in baseline function.
Guanfacine usually reaches its full effect within two to four weeks at a steady dose, though some people notice it still building through week six. By this point you and your prescriber should have a clear sense of whether the medication is working for you.
Once at steady state, non-stimulants are typically reviewed at three to six month intervals. Daily logging across the first eight weeks gives the prescriber the evidence they need to confirm response.
ADHDose makes the milestone view concrete. Daily logs of focus, sleep, energy and side effects across the titration window show the trajectory clearly, to you, and to your prescriber when review day arrives.