Hello dear
Understand your concern.
Clonidine is alfa 2 agonist.
Clonidine is a medication used to treat 
high blood pressure, attention deficit 
hyperactivity disorder, anxiety disorders, withdrawal from alcohol, opioids, smoking , migraine, menopausal flushing, diarrhea, and certain pain conditions.
It should be stop gradually not abruptly.
Always consult the doctor before stop it.
Clonidine suppresses sympathetic outflow resulting in lower blood pressure, but sudden discontinuation can cause 
rebound hypertension due to a rebound in sympathetic outflow.
Clonidine therapy withdraw can cause rebound hypertension.
Yo can reintroduction of clonidine for mild cases, alpha blockers for more urgent situations. 
Beta blockers never should be used alone to treat clonidine withdrawal as alpha 
vasoconstriction would still continue.
Hope this may help you.
Best regards
Dr. Saagar