II. Indications
III. Mechanism
- 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
IV. Pharmacokinetics
- Renal and Hepatic Clearance
- Adjust dose for renal or hepatic Impairment
V. 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
VI. Dosing: 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)
VII. Adverse Effects
- Dry Mouth
- Sedation
- Rebound Hypertension
- Less than with Clonidine
VIII. Drug Interactions
-
Thiazide Diuretics
- Increased Antihypertensive effect (Hypotension risk)
IX. Safety
- See Alpha Adrenergic Central Agonist
- Pregnancy Category B (Guanfacine)
- Unknown Safety in Lactation
X. Resources
XI. References
- Olson (2020) Clinical Pharmacology, MedMaster, Miami, p. 64-5
- Hamilton (2010) Tarascon Pocket Pharmacopeia, Jones and Bartlett, p. 76
Images: Related links to external sites (from Bing)
Related Studies
guanfacine (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
GUANFACINE 1 MG TABLET | Generic | $0.39 each |
GUANFACINE 2 MG TABLET | Generic | $0.56 each |
GUANFACINE HCL ER 1 MG TABLET | Generic | $0.21 each |
GUANFACINE HCL ER 2 MG TABLET | Generic | $0.22 each |
GUANFACINE HCL ER 3 MG TABLET | Generic | $0.22 each |
GUANFACINE HCL ER 4 MG TABLET | Generic | $0.24 each |
Ontology: Guanabenz (C0018312)
Definition (MSH) | An alpha-2 selective adrenergic agonist used as an antihypertensive agent. |
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D006143 |
SnomedCT | 372867002, 82951001 |
English | 2,6-Dichlorobenzylideneaminoguanidine, Guanabenz, 2,6 Dichlorobenzylideneaminoguanidine, Hydrazinecarboximidamide, 2-((2,6-dichlorophenyl)methylene)-, guanabenz, Guanabenz [Chemical/Ingredient], GUANABENZ, Guanabenz (product), Guanabenz (substance) |
Swedish | Guanabenz |
Czech | guanabenz |
Finnish | Guanabentsi |
Russian | GUANABENZ, ГУАНАБЕНЗ |
Japanese | グアナベンツ, グアナベンズ |
Polish | Guanabenz |
Spanish | guanabenz (producto), guanabenz (sustancia), guanabenz, Guanabenzo |
French | Guanabenz |
German | Guanabenz |
Italian | Guanabenzo |
Portuguese | Guanabenzo |
Ontology: Wytensin (C0018313)
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D006143 |
English | Wyeth-Ayerst of Guanabenz Acetate, Wyeth Ayerst of Guanabenz Acetate, Acetate Wyeth-Ayerst, Guanabenz, Guanabenz Acetate Wyeth-Ayerst, Wytensin |
Ontology: Guanfacine (C0079466)
Definition (MSH) | A centrally acting antihypertensive agent with specificity towards ADRENERGIC ALPHA-2 RECEPTORS. |
Definition (NCI) | A centrally acting adrenergic agonist with non-stimulant and antihypertensive property. Guanfacine selectively stimulates alpha-2 adrenergic receptors in the central nervous system, thereby resulting in inhibition of sympathetic nervous system outflow. Used alone or in combination with other drugs, this agent causes reduction of peripheral and renal vascular resistance, and lowers both systolic and diastolic blood pressure and heart rate. |
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D016316 |
SnomedCT | 108553003, 372507007 |
English | Guanfacine, Benzeneacetamide, N-(aminoiminomethyl)-2,6-dichloro-, Guanfacine [Chemical/Ingredient], guanFACINE, GuanFACINE, guanfacine (medication), guanfacine, GUANFACINE, Guanfacine (product), Guanfacine (substance) |
Swedish | Guanfacin |
Czech | guanfacin |
Finnish | Guanfasiini |
Russian | GUANFATSIN, ГУАНФАЦИН |
Japanese | グアンファシン |
Polish | Guanfacyna |
Spanish | guanfacina (producto), guanfacina (sustancia), guanfacina, Guanfacina |
French | Guanfacine |
German | Guanfacin |
Italian | Guanfacina |
Portuguese | Guanfacina |
Ontology: Tenex (C0242580)
Concepts | Pharmacologic Substance (T121) , Organic Chemical (T109) |
MSH | D016316 |
English | tenex, Tenex |