The principal adverse effects of<unk>  are sedation, dry mouth, and hypotension (low blood pressure). By frequency Very common (>10% frequency): * Dizziness * Orthostatic hypotension * Somnolence (dose-dependent) * Dry mouth * Headache (dose-dependent) * Fatigue * Skin reactions (if given transdermally) * Hypotension Common (1-10% frequency): * Anxiety * Constipation * Sedation (dose-dependent) * Nausea/vomiting * Malaise * Abnormal LFTs * Rash * Weight gain/loss * Pain below the ear (from salivary gland) * Erectile dysfunction Uncommon (0.1-1% frequency): * Delusional perception * Hallucination * Nightmare * Paresthesia * Sinus bradycardia * Raynaud's phenomenon * Pruritus * Urticaria Rare (<0.1% frequency): * Gynaecomastia * Impaired ability to cry * Atrioventricular block * Nasal dryness * Colonic pseudo-obstruction * Alopecia * Hyperglycemia Withdrawal Because<unk>  suppresses sympathetic outflow, resulting in lower blood pressure, sudden discontinuation can result in acute hypertension due to a rebound in sympathetic outflow. In extreme cases, this can result in a hypertensive crisis, which is a medical emergency.<unk>  therapy should generally be gradually tapered when discontinuing therapy to avoid rebound effects from occurring. Treatment of<unk>  withdrawal hypertension depends on the severity of the condition. Reintroduction of<unk>  for mild cases, alpha and beta blockers for more urgent situations. Beta blockers never should be used alone to treat<unk>  withdrawal as alpha vasoconstriction would still continue.
Clonidine
Brimonidine
Phenylephrine
Metergoline
Acebutolol
Prazosin
Drospirenone
Avacopan