Drug reference

Guanfacine

Alpha-2 Agonist · Agent for Attention Deficit Hyperactivity Disorder

Also known as Intuniv, Tenex, Guanfacine hydrochloride

Alpha-2 AgonistAgent for Attention Deficit Hyperactivity DisorderATC C02AC02

CDSCO approvedSchedule HATC C02AC02

EXCRETION

—

not curated

INTERACTIONS

12 major

SEVERE in our sources

PREGNANCY

Manufacturer advises avoid unless potential

FDA category + note

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Mechanism

Guanfacine is a selective alpha-2 receptor agonist. It lowers blood pressure by activating brainstem receptors, leading to suppression of sympathetic activity and a reduction in sympathetic tone in the CNS. This sympatholytic action is responsible for its therapeutic effects in conditions like hypertension and ADHD.

Indications

ADHD (children aged 6-17 years)HypertensionTourette's syndrome (off-label)Hyperhidrosis (off-label)Mania (off-label)Posthepatic neuralgia (off-label)Psychosis (off-label)Restless leg syndrome (off-label)Ulcerative colitis (off-label)Allergy-induced inflammatory reactions in patients with extrinsic asthma (off-label)attention-deficit/hyperactivity disorder (ADHD)

Dosing

Adult: with guanfacine p. 370 treatment, the dose should be reduced or an alternative treatment offered. h Other treatment options such as bupropion hydrochloride p. 521, modaﬁnil p. 514, tricyclic antidepressants, and venlafaxine p. 386 [all unlicensed] have been used in the management of ADHD, but due to limited evidence their use is not recommended without specialist advice.…

Pharmacokinetics

Half-life

12-24 hours

Bioavailability

Well absorbed after oral administration

Metabolism

The rest is metabolized

Excretion

About 50% appears unchanged in the urine

Contraindications

abrupt discontinuation (withdrawal syndrome)

Side effects

Common

DizzinessSyncopeSedationdry mouthBradycardiaFatigueConstipationOrthostatic hypotension

Serious

Withdrawal syndrome (upon abrupt discontinuation)
Hypotension
Cardiovascular adverse effects
Hypertensive crisis following abrupt withdrawal

Pregnancy & lactation

Pregnancy

Manufacturer advises avoid unless potential