https://medixway.com/guanfacine-vs-clonidine/

Guanfacine and clonidine are both alpha-2 adrenergic agonists primarily used to treat high blood pressure, but they have differing profiles and additional indications. Guanfacine is more selective for the alpha-2A receptor subtype, which is believed to contribute to its cognitive and behavioral effects. It is commonly prescribed for Attention Deficit Hyperactivity Disorder (ADHD), particularly the extended-release form (Intuniv). Clonidine, although less selective, has broader applications including ADHD, opioid withdrawal, and sleep disorders.In terms of side effects, both can cause sedation, dry mouth, and hypotension. However, clonidine tends to have a shorter half-life, requiring more frequent dosing, and may cause more rebound hypertension if abruptly discontinued. Guanfacine's longer half-life allows for once-daily dosing and potentially fewer withdrawal effects.