Pharm
Guanabenz
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Guanabenz
, Wytensin, Guanfacine, Tenex
See Also
Alpha Adrenergic Central Agonist
Clonidine
Methyldopa
Indications
Hypertension
Attention Deficit Disorder
Motor
Tic Disorder
Mechanism
See
Alpha Adrenergic Central Agonist
See
Alpha Adrenergic Receptor
Central Acting
Adrenergic Agonist
s
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
Pharmacokinetics
Renal and
Hepatic Clearance
Adjust dose for renal or hepatic
Impairment
Dosing
Guanabenz (Wytensin)
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)
Dosing
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
Adverse Effects
Dry Mouth
Sedation
Rebound
Hypertension
Less than with
Clonidine
Drug Interactions
Thiazide Diuretic
s
Increased antihypertensive effect (
Hypotension
risk)
References
Olson (2020) Clinical
Pharmacology
, MedMaster, Miami, p. 64-5
Hamilton (2010) Tarascon Pocket Pharmacopeia, Jones and Bartlett, p. 76
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