DRUG SUPPLIED DOSE COMMENTS
GUANFACINE (Paeds)
(Intuniv XR, Non-formulary at BCCH)

Mechanism of action:

In ADHD, guanfacine works by strengthening regulation of attention and behavior by the prefrontal cortex. These enhancing effects on prefrontal cortical functions are believed to be due to drug stimulation of post-synaptic alpha2A adrenoceptors on dendritic spines. Activating alpha2A adrenoceptors within the central nervous system may lead to reduced peripheral sympathetic outflow and thus a reduction in peripheral sympathetic tone, which lowers both systolic and diastolic blood pressure.




Ref: 32, 44, 83, 160, 513




Last update: 2021-08-03
Non-formulary at BCCH

Extended-release tablet: 1 mg, 2 mg, 3 mg, 4 mg
 ADHD:
>=6 years old (adjunct to stimulant) or
6-12 years old (monotherapy):
Initial dose: 1 mg daily; Increase by
1 mg/day at weekly intervals to maximum of 4 mg/day.

>=13 years old (monotherapy):
Initial dose: 1 mg daily; Increase by
1 mg/day at weekly intervals to maximum of 7 mg/day.
Gradually titrate up to target dosage to prevent somnolence, dizziness, hypotension and syncope.

Dose may be taken once daily in the morning or at bedtime. Administration approximately 5 hours before intended bedtime may help promote sleep and minimize daytime sedation.

XR tablet must be swallowed whole; do not break, crush or chew. Doing so increases rate of drug release and may increase adverse effects.

Guanfacine immediate release (IR) tablets are not available in Canada. Published dosing guidelines for the IR formulation are not applicable to the XR formulation.

To discontinue treatment, gradually decrease dose by 1 mg/day every 3-7 days to avoid rebound hypertension.



Standard Prescription:

Guanfacine __ mg daily PO

Swallow whole, do not break, crush or chew tablet.