Guanfacine (Extended-Release)

How it works

As a selective alpha-2A adrenergic agonist it modulates noradrenergic signalling in the prefrontal cortex, strengthening regulation of attention, impulse control and behaviour rather than acting as a stimulant.

Prescribing in practice

• In this paediatric ADHD population it can cause dose-related sedation, hypotension and bradycardia, so titrate slowly, monitor blood pressure, heart rate and weight, and assess cardiovascular history before starting.
• The extended-release tablets must be swallowed whole and not crushed, split or given with high-fat meals, and must not be interchanged on a milligram basis with immediate-release guanfacine.
• Avoid abrupt discontinuation because of the risk of rebound hypertension; the dose should be tapered, and caution is needed with other sedating or hypotensive agents.

Monitoring

Monitor heart rate, blood pressure, weight, sedation and for syncope during titration, maintenance and after any dose change or discontinuation.

Counselling the patient

• Swallow the tablet whole and never with a fatty meal.
• Do not stop suddenly, as blood pressure can rebound; report fainting or marked drowsiness.
• Drowsiness is common at first and can affect school activities until the dose settles.

Evidence & guidelines

NICE ADHD guidance positions guanfacine as a non-stimulant option for children and young people when stimulants are not tolerated or effective.