Guanabenz

Aka: Guanabenz, Wytensin, Guanfacine, Tenex

1. See Also
   1. Alpha Adrenergic Central Agonist
   2. Clonidine
   3. Methyldopa
2. Indications
   1. Hypertension
   2. Attention Deficit Disorder
   3. Motor Tic Disorder
3. Mechanism
   1. See Alpha Adrenergic Central Agonist
   2. See Alpha Adrenergic Receptor
   3. Central Acting Adrenergic Agonists
      1. Activate alpha-2 receptors that inhibit CNS sympathetic signals
      2. Results in increased parasympathetic effects and side effects
   4. Peripheral Adrenergic Nerve terminal activity
      1. Depletes Norepinephrine stores
4. Pharmacokinetics
   1. Renal and hepatic clearance
   2. Adjust dose for renal or hepatic Impairment
5. Dosing: Guanabenz (Wytensin)
   1. Adult: 2 to 4 mg orally twice daily (up to 32 mg twice daily)
   2. Child (over age 12): 0.25 to 1 mg orally twice daily (up to 2 to 12 mg orally twice daily)
6. Dosing: Guanfacine (Tenex)
   1. Adults and children >12 years
      1. Start 1 mg orally at bedtime
      2. Most effective dose is 1 mg
         1. May increase to 2-3 mg at bedtime after 3-4 weeks (as needed)
         2. Maximum: 3 mg/day
7. Adverse Effects
   1. Dry Mouth
   2. Sedation
   3. Rebound Hypertension
      1. Less than with Clonidine
8. Drug Interactions
   1. Thiazide Diuretics
      1. Increased antihypertensive effect (Hypotension risk)
9. References
   1. Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 64-5
   2. Hamilton (2010) Tarascon Pocket Pharmacopeia, Jones and Bartlett, p. 76