Guanfacine

How it works

It stimulates postsynaptic alpha-2A adrenoceptors in the prefrontal cortex, strengthening regulation of attention and behaviour; this central sympathetic modulation also lowers blood pressure.

Prescribing in practice

• It can cause hypotension, bradycardia and sedation, and abrupt withdrawal may produce rebound hypertension, so it must be tapered rather than stopped suddenly.
• Blood pressure, heart rate and weight should be assessed before and during treatment, with caution where there is cardiovascular disease.
• Sedation and effects on blood pressure are increased by other CNS depressants and antihypertensives; dosing for children should follow a children's formulary.

Monitoring

Monitor blood pressure, heart rate, weight and somnolence at baseline and periodically during treatment and on dose change.

Counselling the patient

• May cause drowsiness, especially when starting; take care with activities needing alertness.
• Do not stop the medicine suddenly as blood pressure can rise; reduce gradually as advised.
• Report fainting, dizziness or a very slow heartbeat.

Evidence & guidelines

Guanfacine is recommended by NICE as a non-stimulant option for ADHD in children and young people where stimulants are unsuitable or ineffective.