SYMPATHOMIMETICS›ALPHA 2 -ADRENOCEPTOR
AGONISTS
Guanfacine 26-May-2016
lINDICATIONS AND DOSE
Attention deficit hyperactivity disorder in children for
whom stimulants are not suitable, not tolerated or
ineffective (initiated under specialist supervision)
▶BY MOUTH
▶Child 6–12 years (body-weight 25 kg and above):Initially
1 mg once daily; adjusted in steps of 1 mg every week if
necessary and if tolerated; maintenance
0. 05 – 0. 12 mg/kg once daily (max. per dose 4 mg), for
optimal weight-adjusted dose titrations, consult
product literature
▶Child 13–17 years (body-weight 34–41.4 kg):Initially 1 mg
once daily; adjusted in steps of 1 mg every week if
necessary and if tolerated; maintenance
0. 05 – 0. 12 mg/kg once daily (max. per dose 4 mg), for
optimal weight-adjusted dose titrations, consult
product literature
▶Child 13–17 years (body-weight 41.5–49.4 kg):Initially
1 mg once daily; adjusted in steps of 1 mg every week if
necessary and if tolerated; maintenance
0. 05 – 0. 12 mg/kg once daily (max. per dose 5 mg), for
optimal weight-adjusted dose titrations, consult
product literature
▶Child 13–17 years (body-weight 49.5–58.4 kg):Initially
1 mg once daily; adjusted in steps of 1 mg every week if
necessary and if tolerated; maintenance
0. 05 – 0. 12 mg/kg once daily (max. per dose 6 mg), for
optimal weight-adjusted dose titrations, consult
product literature
▶Child 13–17 years (body-weight 58.5 kg and above):Initially
1 mg once daily; adjusted in steps of 1 mg every week if
necessary and if tolerated; maintenance
0. 05 – 0. 12 mg/kg once daily (max. per dose 7 mg), for
optimal weight-adjusted dose titrations, consult
product literature
DOSE ADJUSTMENTS DUE TO INTERACTIONS
▶Manufacturer advises reduce dose by half with
concurrent use of moderate and potent inhibitors of
CYP 3 A 4.
▶Manufacturer advises increase dose up to max. 7 mg
daily with concurrent use of potent inducers of
CYP 3 A 4 —no specific recommendation made for
children.lCAUTIONSBradycardia (risk of torsade de pointes).heart
block (risk of torsade de pointes).history of cardiovascular
disease.history of QT-interval prolongation.
hypokalaemia (risk of torsade de pointes)
lINTERACTIONS→Appendix 1 : guanfacine
lSIDE-EFFECTS
▶Common or very commonAnxiety.appetite decreased.
arrhythmias.asthenia.constipation.depression.
diarrhoea.dizziness.drowsiness.dry mouth.
gastrointestinal discomfort.headache.hypotension.
mood altered.nausea.skin reactions.sleep disorders.
urinary disorders.vomiting.weight increased
▶UncommonAsthma.atrioventricular block.chest pain.
hallucination.loss of consciousness.pallor.seizure.
syncope
▶Rare or very rareHypertension.hypertensive
encephalopathy.malaise
▶Frequency not knownErectile dysfunction
SIDE-EFFECTS, FURTHER INFORMATIONSomnolence and
sedation may occur, predominantly during thefirst 2 -
3 weeks of treatment and with dose increases;
manufacturer advises to consider dose reduction ordiscontinuation of treatment if symptoms are clinically
significant or persistent.
Overdose Features may include hypotension, initial
hypertension, bradycardia, lethargy, and respiratory
depression. Manufacturer advises that patients who
develop lethargy should be observed for development of
more serious toxicity for up to 24 hours.
lCONCEPTION AND CONTRACEPTIONManufacturer
recommends effective contraception in females of
childbearing potential.
lPREGNANCYManufacturer advises avoid—toxicity in
animalstudies.
lBREAST FEEDINGManufacturer advises avoid—present in
milk inanimalstudies.
lHEPATIC IMPAIRMENT
Dose adjustmentsManufacturer advises consider dose
reduction.
lRENAL IMPAIRMENT
Dose adjustmentsManufacturer advises consider dose
reduction in severe impairment and end-stage renal
disease.
lMONITORING REQUIREMENTS
▶Manufacturer advises to conduct a baseline evaluation to
identify patients at risk of somnolence, sedation,
hypotension, bradycardia, QT-prolongation, and
arrhythmia; this should include assessment of
cardiovascular status. Monitor for signs of these adverse
effects weekly during dose titration and then every
3 months during thefirst year of treatment, and every
6 months thereafter. Monitor BMI prior to treatment and
then every 3 months for thefirst year of treatment, and
every 6 months thereafter. More frequent monitoring is
advised following dose adjustments.
▶Monitor blood pressure and pulse during dose downward
titration and following discontinuation of treatment.
lTREATMENT CESSATIONManufacturer advises avoid abrupt
withdrawal; consider dose tapering to minimise potential
withdrawal effects.
lDIRECTIONS FOR ADMINISTRATIONManufacturer advises
avoid administration with high fat meals (may increase
absorption).
lPATIENT AND CARER ADVICEPatients or carers should be
counselled on administration of guanfacine modified-
release tablets.
Missed dosesManufacturer advises that patients and
carers should inform their prescriber if more than one dose
is missed; consider dose re-titration.
Driving and skilled tasksManufacturer advises patients and
carers should be counselled about the effects on driving
and performance of skilled tasks—increased risk of
dizziness and syncope.lMEDICINAL FORMS
There can be variation in the licensing of different medicines
containing the same drug.
Modified-release tablet
CAUTIONARY AND ADVISORY LABELS2, 25
▶Intuniv(Shire Pharmaceuticals Ltd)A
Guanfacine (as Guanfacine hydrochloride) 1 mgIntuniv 1 mg
modified-release tablets| 28 tabletP£ 56. 00
Guanfacine (as Guanfacine hydrochloride) 2 mgIntuniv 2 mg
modified-release tablets| 28 tabletP£ 58. 52
Guanfacine (as Guanfacine hydrochloride) 3 mgIntuniv 3 mg
modified-release tablets| 28 tabletP£ 65. 52
Guanfacine (as Guanfacine hydrochloride) 4 mgIntuniv 4 mg
modified-release tablets| 28 tabletP£ 76. 16BNFC 2018 – 2019 Attention deficit hyperactivity disorder 231
Nervous system4