About guanfacine

Guanfacine is an alpha₂-adrenergic receptor agonist licensed for treating attention deficit hyperactivity disorder (ADHD).

A National Patient Safety Alert was issued on the 27 September 2023 for the shortage of guanfacine prolonged-release tablets.

Avoid abrupt withdrawal

Abrupt withdrawal should be avoided because serious withdrawal effects can occur. Symptoms include:

• confusion
• constipation
• headaches
• increased blood pressure
• nausea
• nervousness or agitation
• rapid heartbeats
• stomach pain
• tremors

In addition to the symptoms listed above, very rare cases of hypertensive encephalopathy have been reported.

Availability

Prescribing available medicines to treat ADHD contains an overview of the current supply position and is regularly updated as the national stock situation continues to evolve.

The SPS Medicines Supply Tool has further information on shortage of guanfacine (Intuniv) modified-release tablets including details on specialist importers.

New patients

Do not initiate prescribing of medication that is listed in short supply for any new patient, unless they have been recruited to the SATURN clinical trial.

Seek specialist advice for alternative treatment options.

Existing patients

Identify patients taking guanfacine as a priority. Contact them to confirm their remaining supply, and ensure patients and carers are aware of the risks with abrupt withdrawal.

In line with NICE guidance, discuss using the current medicine supply disruption as an opportunity for a management plan to trial a period of stopping the medicine or reducing the dose. This can be considered when an assessment of the overall balance of benefits and harms suggests it may be appropriate.

Continuing guanfacine

If the patient wants to continue guanfacine, check availability of the licensed product and supply accordingly.

If supplies are unavailable to continue treatment, consider generic prescribing in collaboration with specialists and endorse prescription with “special order” to enable pharmacy to import through specialist wholesalers if possible. Take into account of national guidance related to the prescribing of unlicensed medicines or prescribing outside of the product licence.

Stopping guanfacine

If the patient wishes to stop treatment with guanfacine, seek urgent specialist advice to ensure a management plan is in place to avoid abrupt withdrawal.

Dose tapering

Dose tapering may be advised by the specialist.

Intuniv SPC and risk materials provides further information if dose tapering and subsequent monitoring is needed. An example of a dose tapering schedule is reducing guanfacine by 1mg every 3 to 7 days until stop. Monitor for changes in blood pressure and pulse.

Unable to taper dose

In exceptional cases where it is not possible to slowly reduce guanfacine, suggested actions after stopping guanfacine are:

• monitor blood pressure and pulse on day 2 and day 4
• if blood pressure is raised at day 4, continue measuring blood pressure and pulse once a week until it reaches baseline

The hypotensive effects of guanfacine may take around 2 to 4 days to resolve. However, there are a few reports of increased blood pressure persisting. If there are signs of clinically significant rebound hypertension, seek further medical advice as clinically appropriate.

Useful resources

The following links signpost to national guidance for healthcare professionals:

• GMC – Prescribing unlicensed medicines 
• MHRA – The supply of unlicensed medicines products (“specials”)
• RPS – Professional guidance for procurement and supply of specials

Using unlicensed medicines is a resource produced by SPS that may be helpful.

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