- See Alpha Adrenergic Central Agonist
- See Alpha Adrenergic Receptor
- Central Acting Adrenergic Agonists
- Activates alpha-2 receptors that inhibit CNS preganglionic sympathetic signals, lowering Blood Pressure
- Results in increased parasympathetic effects and side effects (e.g. sedation)
- Peripheral Adrenergic Nerve terminal activity
- Depletes Norepinephrine stores
- Renal and Hepatic Clearance
- Adjust dose for renal or hepatic Impairment
- Guanfacine (Tenex)
- Adults and children age >12 years
- Start 1 mg orally at bedtime
- Most effective dose is 1 mg
- May increase to 2-3 mg at bedtime after 3-4 weeks (as needed)
- Maximum: 3 mg/day
- Guanabenz (Wytensin)
- Listed for historical purposes only (discontinued in U.S. outside of use in horses)
- Adult: 2 to 4 mg orally twice daily (up to 32 mg twice daily)
- Child (over age 12): 0.25 to 1 mg orally twice daily (up to 2 to 12 mg orally twice daily)
- Dry Mouth
- Sedation
- Rebound Hypertension
- Less than with Clonidine
-
Thiazide Diuretics
- Increased Antihypertensive effect (Hypotension risk)
- See Alpha Adrenergic Central Agonist
- Pregnancy Category B (Guanfacine)
- Unknown Safety in Lactation
- Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 64-5
- Hamilton (2010) Tarascon Pocket Pharmacopeia, Jones and Bartlett, p. 76