Title: Guanfacine
CAS Registry Number: 29110-47-2
CAS Name: N-(Aminoiminomethyl)-2,6-dichlorobenzeneacetamide
Additional Names: N-amidino-2-(2,6-dichlorophenyl)acetamide; [(2,6-dichlorophenyl)acetyl]guanidine
Molecular Formula: C9H9Cl2N3O
Molecular Weight: 246.09
Percent Composition: C 43.93%, H 3.69%, Cl 28.81%, N 17.08%, O 6.50%
Literature References: Centrally acting a2-adrenoceptor agonist. Prepn: J. B. Bream, C. W. Picard, FR 1584670; eidem, US 3632645 (1969, 1972, both to Wander). Pharmacology: D. M. Coward et al., Arzneim.-Forsch. 27, 2326 (1977); H. F. Oates et al., Arch. Int. Pharmacodyn. Ther. 231, 148 (1978); eidem, Clin. Exp. Pharmacol. Physiol. 6, 61 (1979). Determn in biological fluids: M. Guerrat et al., J. Pharm. Sci. 68, 219 (1979). Kinetics: Y. A. Weiss et al., Clin. Pharmacol. Ther. 25, 283 (1979). Clinical studies: U. C. Dubach et al., Arzneim.-Forsch. 27, 674 (1977); P. MacCarthy et al., Clin. Exp. Pharmacol. Physiol. 5, 187 (1978). Symposium on pharmacology, pharmacokinetics, clinical efficacy and comparison with clonidine: Am. J. Cardiol. 57, 1E-61E (1986). Review: Br. J. Clin. Pharmacol. 10, Suppl. 1, 1S-208S (1980).
Properties: White grains from methanol/ether, mp 225-227°.
Melting point: mp 225-227°
Derivative Type: Hydrochloride
CAS Registry Number: 29110-48-3
Manufacturers' Codes: BS-100-141; LON-798
Trademarks: Estulic (Novartis); Tenex (ESP)
Molecular Formula: C9H9Cl2N3O.HCl
Molecular Weight: 282.55
Percent Composition: C 38.26%, H 3.57%, Cl 37.64%, N 14.87%, O 5.66%
Properties: White needles, mp 213-216°. LD50 in mice: 165 mg/kg orally (Coward).
Melting point: mp 213-216°
Toxicity data: LD50 in mice: 165 mg/kg orally (Coward)
Therap-Cat: Antihypertensive.
Keywords: a-Adrenergic Agonist; Antihypertensive; Guanidine Derivatives.
Guanidine Guanidinium Aluminum Sulfate Hexahydrate Guano Guanochlor Guanosine

Systematic (IUPAC) name
Clinical data
Trade names Tenex, Intuniv
AHFS/ monograph
MedlinePlus a601059
Licence data US Daily Med:link
Pregnancy cat. B (US)
Legal status -only (US)
Routes oral, intravenous
Pharmacokinetic data
Bioavailability 80-100% (IR), 58% (XR)[1][2]
Protein binding 70%[1][2]
Metabolism CYP3A4[1][2]
Half-life 17 hours (IR; range: 10-30 hours), 18 hours (XR), 13-14 hours (Paediatrics)[1][2]
Excretion renal (80%; 50% [range: 40-75%] as unchanged drug)[1][2]
CAS number 29110-47-2 YesY
ATC code C02AC02
PubChem CID 3519
IUPHAR ligand 522
DrugBank DB01018
ChemSpider 3399 YesY
KEGG D08031 N
Chemical data
Formula C9H9Cl2N3O 
Mol. mass 246.093 g/mol
 N (what is this?)  (verify)

Guanfacine (brand name Tenex, and the extended release Intuniv) is a sympatholytic. It is a selective α2A receptor agonist. These receptors are concentrated heavily in the prefrontal cortex and the locus coeruleus, with the potential to improve attention resulting from interaction with receptors in the former.[3] Guanfacine lowers both systolic and diastolic blood pressure by activating the central nervous system α2A norepinephrine autoreceptors, which results in reduced peripheral sympathetic outflow and thus a reduction in peripheral sympathetic tone.[4]