Guanfacine

Chemical structure of Guanfacine.

Guanfacine is a pharmaceutical medication sold under the brand names Tenex for its immediate-release form and Intuniv in its extended-release variant. As a sympatholytic drug, its primary applications are in the treatment of hypertension and attention-deficit hyperactivity disorder (ADHD). Guanfacine works as a selective α2A receptor agonist, predominantly interacting with receptors located in the prefrontal cortex and the locus coeruleus. Such interactions enhance attention span and behavioral self-control while also decreasing both systolic and diastolic blood pressure by triggering the central nervous system's α2A norepinephrine autoreceptors.

Medical Uses

Hypertension

Guanfacine has demonstrated efficacy in managing both acute and chronic hypertension. Research has indicated that patients treated with guanfacine experienced blood pressure stabilization rates of 54% over one year and 66% over two years.

Attention-Deficit Hyperactivity Disorder

The Food and Drug Administration (FDA) has approved the extended-release formulation of guanfacine, labeled as Intuniv, for ADHD treatment in individuals aged 6 to 17 years. The drug's mechanism, which strengthens the prefrontal cortical network connections via its influence on post-synaptic α2A adrenergic receptors, is believed to facilitate better regulation of attention, emotion, and behavior.

Guanfacine, when combined with stimulants, may enhance therapeutic outcomes, offset side effects, diminish rebound effects, and, if consumed at night, promote sleep. Animal studies have underscored its positive impact on cognitive attributes like working memory, attention span, response inhibition, and impulse control. Notably, these benefits are most evident in subjects with cognitive impairments.

Further, guanfacine offers potential therapeutic benefits for patients suffering from various prefrontal cortical disorders, including frontal lobe traumatic brain injuries, cognitive-impacting strokes, and emotional behavior disorders.

Treatment of Withdrawal Syndrome

Guanfacine is currently under investigation as a potential treatment for withdrawal syndromes related to substances such as opioids, alcohol, and nicotine.

Adverse Effects

Incidence of adverse effects: Very common (>10% incidence) adverse effects:

• Abdominal pain
• Constipation
• Dizziness
• Fatigue
• Headache
• Somnolence
• Xerostomia (dry mouth)

Interactions

Certain drugs may interact with guanfacine, affecting its efficacy or causing adverse reactions:

• CYP3A4/5 inhibitors — Exercise caution as these elevate guanfacine's plasma concentration.
• CYP3A4 inducers — An increased guanfacine dose is advised.
• Valproic acid — Increases the plasma concentration of valproic acid; caution is required.
• Antihypertensive drugs — Risk of additive effects, such as hypotension and syncope.
• CNS depressant drugs — Can add to sedative effects, resulting in heightened sedation or somnolence.

See Also

• Sympatholytic drugs
• Attention-deficit hyperactivity disorder
• Hypertension

See Also

• Hypertension
• Attention-deficit hyperactivity disorder

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