Loading
If this is the first time anyone has visited this substance, we may be fetching live data from TGA Product Information, PBS, and state framework sources — that can take up to a minute. Cached substances load in a second or two.
A plain-language summary of the cited sources below. Informational only — not medical advice.
Guanfacine is a medication that works on specific receptors in the brain called alpha 2A-adrenergic receptors. It is approved in Australia for treating attention deficit hyperactivity disorder in children and adolescents aged 6 to 17. Your family member might be prescribed it on its own when stimulant medications aren't suitable, aren't tolerated, or haven't worked well enough, or it might be added to a stimulant medication if that stimulant alone hasn't given enough benefit.
The medication stays in the body for roughly 18 hours after each dose, which means it builds up to steady levels with once-daily dosing. Guanfacine is broken down mainly by an enzyme in the liver called CYP3A, then further processed before leaving the body.
Side effects that occur in a noticeable number of people include drowsiness, headache, abdominal pain, tiredness, and reduced appetite. These are things to watch for, particularly in the first weeks of treatment. More serious but less common effects have been reported and include fainting or loss of consciousness, very high blood pressure that affects the brain, seizures, changes in heart rhythm visible on an ECG, and suicide-related events including completed suicide, suicide attempt, and suicidal ideation. If your family member faints, has a seizure, or you notice any change in their mood or thoughts about self-harm, seek medical help immediately.
Guanfacine should not be used in anyone who has had an allergic or hypersensitivity reaction to guanfacine or any ingredient in the formulation. The prescribing doctor will take a full medical history to check whether it's safe for your family member.
A plain-language summary of the cited sources below. Informational only — not medical advice.
These are practitioner observations, not TGA-approved indications. A use being off-label does not by itself imply a regulated restrictive practice; review the documented purpose against the observed function in context.
Tier 4 · ObservationAttention deficit hyperactivity disorder Clinical criteria: Treatment Phase: Initial treatment Treatment criteria: Must be treated by a paediatrician or psychiatrist. The condition must be or have been diagnosed according to the DSM-5 criteria, AND Patient must have a contraindication to dexamfetamine, methylphenidate or lisdexamfetamine as specified in TGA-approved product information; OR Patient must have a comorbid mood disorder that has developed or worsened as a result of dexamfetamine, methylphenidate or lisdexamfetamine treatment and is of a severity necessitating treatment withdrawal; OR Patient must be at an unacceptable medical risk of a severity necessitating permanent stimulant treatment withdrawal if given a stimulant treatment with another agent; OR Patient must have experienced adverse reactions of a severity necessitating permanent treatment withdrawal following treatment with dexamfetamine, methylphenidate and lisdexamfetamine (not simultaneously). Population criteria: Patient must be or have been diagnosed between the ages of 6 and 17 years inclusive.
“Guanfacine is a selective alpha 2A -adrenergic receptor agonist.”
“The elimination half-life of guanfacine is approximately 18 hours.”
“In vitro studies with human liver microsomes and recombinant CYPs demonstrated that guanfacine is primarily metabolised via CYP3A-mediated oxidation, with subsequent phase II reactions of sulfation and glucuronidation. In pooled human hepatic microsomes, guanfacine did not inhibit the activities of the major cytochrome P450 isoenzymes (CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, or CYP3A5); guanfacine is also not expected to be an inducer of CYP3A, CYP1A2 and CYP2B6.”
A plain-language summary of the cited sources below. Informational only — not medical advice.
Guanfacine is a selective alpha 2A-adrenergic receptor agonist with low affinity for other receptors; it also acts as a serotonin 5-HT2B receptor agonist. It is TGA-approved for the treatment of attention deficit hyperactivity disorder in children and adolescents aged 6–17 years, either as monotherapy when stimulants or atomoxetine are not suitable, not tolerated, or have been shown to be ineffective, or as adjunctive therapy to psychostimulants where there has been a sub-optimal response to psychostimulants alone.
The elimination half-life is approximately 17–18 hours in adolescents and adults, and approximately 14 hours in children. Guanfacine is primarily metabolised via CYP3A-mediated oxidation, with subsequent sulfation and glucuronidation. It does not inhibit major cytochrome P450 isoenzymes and is not expected to induce CYP3A, CYP1A2, or CYP2B6. Common adverse effects include somnolence, headache, abdominal pain, fatigue, and decreased appetite. Serious adverse effects include syncope or loss of consciousness, hypertensive encephalopathy, convulsion, QT prolongation, and suicide-related events including completed suicide, suicide attempt, and suicidal ideation. Guanfacine is contraindicated in patients with a history of hypersensitivity to guanfacine or its excipients.
Working under the parallel aged-care framework? Aged-care equivalent →
Curated subset. The full adverse-effect list is in the TGA Product Information; click any citation above to open it.