An alpha2-adrenergic agonist .
Trade names Tenex, and Intuniv.
Administered orally and intravenously.
Has a bioavailability of 99.9%, and a half-life of 14.8-18.3 hours.
Really excreted and metabolized by the CYP3A system.
A sympatholytic agent, and is a selective α2A receptor agonist, which are concentrated in the prefrontal cortex and the locus coeruleus, with the potential to improve attention abilities via modulating post-synaptic α2A receptors.
Lowers both systolic and diastolic blood pressure by activating the central nervous system α2A norepinephrine autoreceptors, which results in reduced peripheral sympathetic outflow and thus a reduction in peripheral sympathetic tone.
Side effects are dose dependent.
It reduces hypertension with normalization of blood pressure of 54% treated over a year and 66% over two years.
1 mg Guanfacine tablets.
An extended-release formulation of guanfacine (Intuniv) has also been approved for the treatment of attention-deficit hyperactivity disorder (ADHD) in people ages 6–17.
Extended-release formulation of guanfacine strengthens prefrontal cortical regulation of attention and behavior.
When used in conjunction with stimulants, augment therapeutic actions, counters side effects, reduces rebound, and when taken at night induces sleep.
Improves regulation of behavior, attention, and emotion through actions at post-synaptic α2A adrenergic receptors on prefrontal cortical neurons.
Performance increases in spatial working memory, and may help with prefrontal cortical disorders, including traumatic brain injury to the frontal lobe, strokes affecting higher cognitive function,and emotional disorders.
Used for treatment of anxiety, such as generalized anxiety disorder and post-traumatic stress disorder symptoms.
It reduce sympathetic arousal, weaken the emotional responses of the amygdala, and strengthen prefrontal cortical regulation of emotion, action and thought.
All of these actions likely contribute to the relief of the hyperarousal, re-experiencing of memory, and impulsivity associated with PTSD.
Improves sleep int2242upted by nightmares in PTSD patients.
Side effects: depression, dizziness, drowsiness, headache, constipation, gas pains, diarrhea, loss of appetite, fatigue, and nasal congestion may occur.
Less common side effects include: chest pain, dyspnea, skin rash, swelling, blurred vision, jaundice, mental/mood changes, tingling sensation, dry mouth, impotence, decreased sexual desire, vision changes, taste changes, tinnitus, and leg cramps.
Cardiovascular side effects include orthostatic hypotension, dizziness, palpitations, and tachycardia upon standing, and bradycardia.
Gradual discontinuation is recommended, as rebound hypertension is a possibility with sudden drug withdrawal.
CYP3A4/5 inhibitors elevate plasma concentrations
Has a bioavailability of nearly 100% and half-life of 17 hours.
Eliminated primarily by renal route.
Can mimic effects of norepinephrine
Used for Tourette’s syndrome, oppositional defiance disorder, and ADHD.
At prefrontal cortex can strengthen networks and protect receptors from stress related damage.
Can improve performance and memory with mild traumatic brain injury.