II. Indications
III. Mechanism
- See Alpha Adrenergic Central Agonist
- See Alpha Adrenergic Receptor
- Central Acting Adrenergic Agonists
- Activate alpha-2 receptors that inhibit CNS sympathetic signals
- Results in increased parasympathetic effects and side effects
- Peripheral Adrenergic Nerve terminal activity
- Depletes Norepinephrine stores
IV. Pharmacokinetics
- Renal and hepatic clearance
- Adjust dose for renal or hepatic Impairment
V. 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)
VI. Dosing: Guanfacine (Tenex)
- Adults and children >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
VII. Adverse Effects
- Dry Mouth
- Sedation
- Rebound Hypertension
- Less than with Clonidine
VIII. Drug Interactions
-
Thiazide Diuretics
- Increased antihypertensive effect (Hypotension risk)
IX. 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)
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| Guanfacine (on 6/18/2017 at Walmart.com) | ||
| Guanfacine 1mg | #30 tablets for $4.00 | $0.13 each |
| Guanfacine 1mg | #90 tablets for $10.00 | $0.11 each |
| guanfacine (on 5/17/2017 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| GUANFACINE 1 MG TABLET | Generic | $0.07 each |
| GUANFACINE 2 MG TABLET | Generic | $0.10 each |
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| GUANFACINE HCL ER 4 MG TABLET | Generic | $0.63 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 |
