guanfacine (Rx)

Brand and Other Names:Intuniv, Tenex
  • Print

Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet (Tenex)

  • 1mg
  • 2mg
more...

Hypertension

Tenex: 1 mg PO qHS; may increase to 2 mg after 3-4 weeks

Usual range 0.5-2 mg/day

Do not exceed 3 mg qDay due to increased risk of adverse effects

Heroin Withdrawal (Off-label)

0.03-1.75 mg/day PO for 5-15 days

Migraine Prophylaxis (Off-label)

Initial: 1 mg/day; do not exceed 3 mg/day

Fragile X Syndrome (Orphan)

Orphan sponsor

  • Watson Laboratories, Inc; 311 Bonnie Circle, PO Box 1900; Corona, CA 91718-1900

Dosage Modifications

Strong or moderate CYP3A4 inhibitors

  • Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations
  • FDA-labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the reommended dose; specific recommendations for immediate-release (IR) guanfacine are not available
  • Starting therapy while currently taking CYP3A4 inhibitor: Decrease dose to half the recommended level
  • Continuing therapy while adding CYP3A4 inhibitor: Decrease dose to half the recommended level
  • Continuing therapy while stopping CYP3A4 inhibitor: Increase dose to recommended level

Strong or moderate CYP3A4 inducers

  • CYP3A4 inducers significantly reduce guanfacine plasma concentrations and elimination half-life
  • If coadministered, more frequent dosing of the IR product may be required to achieve or maintain the desired hypotensive response
  • For patients with ADHD, FDA-approved labeling for ER guanfacine recommends that, if coadministered, doubling the recommended dose of guanfacine should be considered
  • Starting therapy while currently taking CYP3A4 inducer: Increase dose up to double the recommended level
  • Continuing therapy while adding CYP3A4 inducer: Increase dose up to double the recommended level over 1-2 weeks
  • Continuing therapy while stopping CYP3A4 inducer: Increase dose to recommended level

Discontinuation of therapy

  • To minimize risk of rebound hypertension upon discontinuation, taper total daily dose in decrements of no more than 1 mg every 3 to 7 days; blood pressure and heart rate should be monitored when reducing dose or discontinuing therapy; follow patients closely for rebound hypertension if abrupt discontinuation occurs (especially with concomitant stimulant use)

Dosage Forms & Strengths

tablet (Tenex)

  • 1mg
  • 2mg

tablet, extended-release (Intuniv)

  • 1mg
  • 2mg
  • 3mg
  • 4mg
more...

Hypertension

<12 years

  • Safety and efficacy not established

≥12 years

  • Tenex: 1 mg PO qHS; may increase to 2-3 mg after 3-4 weeks
  • Usual range: 0.5-2 mg/day

Attention Deficit Hyperactivity Disorder

Intuniv only

Monotherapy for ADHD or adjunct to stimulants

<6 years: Safety and efficacy not established

6-18 years

  • Intuniv: 1 mg/day PO initially; may adjust dose using increasing increments (not exceeding 1 mg/wk)
  • To balance the exposure-related potential benefits and risks, recommended target dose range depending on clinical response and tolerability is 0.05-0.12 mg/kg/day PO initially 
  • Aged 6-12 years: Doses >4 mg/day not evaluated
  • Aged 13-17 years: Doses >7 mg/day not evaluated
  • Adjunctive trials with psychostimulants: Doses >4 mg/day not evaluated

Target dose range by weight

  • 25-33.9 kg: 2-3 mg/day
  • 34-41.4 kg: 2-4 mg/day
  • 41.5-49.4 kg: 3-5 mg/day
  • 49.5-58.4 kg: 3-6 mg/day
  • 58.5-91 kg: 4-7 mg/day
  • >91 kg: 5-7 mg/day

Dosage Modifications

Extended-release tablets

  • Renal impairment: Dose reduction may be necessary in patients with significant impairment of renal function
  • Hepatic impairment: Dose reduction may be necessary in patients with significant impairment of hepatic function

Strong or moderate CYP3A4 inhibitors

  • Strong or moderate CYP3A4 inhibitors (eg, ketoconazole) significantly increase guanfacine plasma concentrations
  • Starting therapy while currently taking CYP3A4 inhibitor: Decrease dose to half the recommended level
  • Continuing therapy while adding CYP3A4 inhibitor: Decrease dose to half the recommended level
  • Continuing therapy while stopping CYP3A4 inhibitor: Increase dose to recommended level

Strong or moderate CYP3A4 inducers

  • CYP3A4 inducers (eg, carbamazepine) significantly reduce guanfacine plasma concentrations and elimination half-life
  • If coadministered, more frequent dosing of the IR product may be required to achieve or maintain the desired hypotensive response
  • Extended-release tablets
    • Starting therapy while currently taking CYP3A4 inducer: Increase dose up to double the recommended level
    • Continuing therapy while adding CYP3A4 inducer: Increase dose up to double the recommended level over 1-2 weeks
    • Continuing therapy while stopping CYP3A4 inducer: Decrease dose to recommended level over 1-2 weeks

Dosing Considerations

Immediate-release and extended-release formulations are not interchangeable due to differences in bioavailability

If switching from immediate-release guanfacine, discontinue treatment; titrate with extended-release tablets following recommended schedule

Discontinuation of extended-release guanfacine

  • Following discontinuation of extended-release tablets, patients may experience increases in blood pressure and heart rate
  • Monitor blood pressure and pulse when reducing dose or discontinuing treatment
  • Taper daily dose in decrements of ≤1 mg q3-7d to minimize the risk of rebound hypertension

Tourette Syndrome (Orphan)

Orphan designation for combination of guanfacine and amphetamine to treatment Tourette syndrome

Sponsor

  • Genco Sciences, LLC; 1011 Greenwood Avenue; Willmette, Illinois 60091
Next:

Interactions

Interaction Checker

and guanfacine

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

            All Interactions Sort By:
             activity indicator 
            Previous
            Next:

            Adverse Effects

            >10%

            Xerostomia (10-60%)

            Somnolence (5-39%)

            Headache (0.2-26%)

            Dizziness (2-15%)

            Constipation (2-16%)

            Fatigue (2-15%)

            Abdominal pain (11%)

            Extended-release tablets

            • Somnolence (6-38%)
            • Headache (23%)
            • Dizziness (6-16%)
            • Decreased appetite (6-15%)
            • Fatigue (2-14%)
            • Abdominal pain (11%)

            1-10%

            Hypotension (7%)

            Asthenia (2-7%)

            Impotence (0-7%)

            Lethargy (6%)

            Dizziness (6%)

            Irritability (6%)

            Nausea (3-6%)

            Decreased appetite (5%)

            Weakness (1-5%)

            Insomnia (3-4%)

            Bradycardia (3%)

            Palpitations (3%)

            Confusion (3%)

            Depression (3%)

            Dyspnea (3%)

            Alopecia (3%)

            Dermatitis (3%)

            Diaphoresis (3%)

            Pruritus (3%)

            Dyspepsia (3%)

            Dysphagia (3%)

            Hypokinesia (3%)

            Leg cramps (3%)

            Extended-release tablets

            • Hypotension (7%)
            • Insomnia (7%)
            • Irritability (6%)
            • Lethargy (6%)
            • Nausea (6%)
            • Postural dizziness (5%)
            • Bradycardia (5%)
            • Diarrhea (5%)
            • Anxiety (5%)
            • Dry mouth (3-4%)
            • Constipation (3%)
            • Increased weight (3%)
            • Rash (3%)
            • Nightmare (2%)
            • Enuresis (2%)

            Frequency Not Defined

            Orthostatic hypotension

            Exfoliation

            Rash

            Arthralgia

            Myalgia

            Extended-release tablets

            • Atrioventricular block
            • Asthenia
            • Chest pain
            • Hypersensitivity
            • Increased alanine aminotransferase
            • Convulsion Increased urinary frequency
            • Hypertension
            • Pallor

            Postmarketing Reports

            Cardiovascular: Bradycardia, palpitations, syncope, tachycardia, rebound hypertension, hypertensive encephalopathy

            CNS: Paresthesias, vertigo

            GI: Abdominal pain, constipation, diarrhea, dyspepsia

            Liver/biliary: Abnormal LFTs

            Musculoskeletal: Arthralgia, leg cramps, leg pain, myalgia

            Psychiatric: Agitation, anxiety, confusion, depression, hallucinations, insomnia, nervousness

            Reproductive: Impotence

            Respiratory: Dyspnea

            Skin: Alopecia, dermatitis, exfoliative dermatitis, pruritus, rash

            Sensory: Blurred vision, alterations in taste

            Urinary: Nocturia, urinary frequency

            Other: Asthenia, chest pain, edema, malaise, tremor

            Extended-release tablets

            • General: Edema, malaise, tremor
            • Cardiovascular: Palpitations, tachycardia, rebound hypertension, hypertensive encephalopathy
            • Central nervous system: Paresthesias, vertigo
            • Eye disorders: blurred vision
            • Musculoskeletal System: Arthralgia, leg cramps, leg pain, myalgia
            • Psychiatric: Confusion, hallucinations
            • Reproductive system, male: Erectile dysfunction
            • Respiratory System: Dyspnea
            • Skin and appendages: Alopecia, dermatitis, exfoliative dermatitis, pruritus, rash
            • Special senses: Alterations in taste
            Previous
            Next:

            Warnings

            Contraindications

            Hypersensitivity

            Cautions

            Avoid abrupt withdrawal (can result in anxiety, nervousness, and rebound hypertension)

            May cause hypotension, orthostasis, bradycardia, and syncope, use with caution in history of cerebrovascular disease, recent MI, severe coronary insufficiency, or syncope

            Chronic renal/hepatic failure

            May cause sedation, especially at start; avoid operating heavy machinery

            Skin rash with exfoliation reported

            Avoid concomitant use with other CNS depressants (eg, alcohol) as they may potentiate CNS effects

            Risk of cardiovascular effects may increase when administered concurrently with antihypertensive medications or drugs that affect heart rate

            In post marketing experience, abrupt discontinuation of the extended-release tablets has resulted in clinically significant and persistent rebound hypertension above baseline levels and increases in heart rate; hypertensive encephalopathy reported in association with rebound hypertension with guanfacine

            ADHD

            • Hypotension is dose-limiting
            • Do not substitute extended-release tablet for immediate-release guanfacine on a mg/mg basis, because of differing pharmacokinetic profiles
            • May cause dose-dependent hypotension, bradycardia, and syncope
            • Hallucinations reported in children with ADHD treated with guanfacine

            Geriatric patients

            • May cause adverse CNS effects
            • May cause bradycardia and orthostatic hypotension
            • Not recommended as routine treatment for hypertension (Beers criteria)
            Previous
            Next:

            Pregnancy & Lactation

            Pregnancy

            There are no adequate and well-controlled studies of extended-release guanfacine in pregnant women

            No fetal harm observed in rats and rabbits with administration of guanfacine at 4 and 2.7 times, respectively, the maximum recommended human dose; owing to animal studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed

            Lactation

            It is not known whether guanfacine is excreted in human milk; however, guanfacine is excreted in rat milk

            Exercise caution when extended-release guanfacine is administered to a nursing woman

            Observe human milk-fed infants for sedation and somnolence

            Pregnancy Categories

            A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA:Information not available.

            more...
            Previous
            Next:

            Pharmacology

            Mechanism of Action

            Selective alpha2-adrenergic receptor agonist causing decreased sympathetic outflow and subsequent decrease in vasomotor tone and heart rate; may preferentially bind postsynaptic alpha2A adrenoreceptors in the prefrontal cortex, which may improve delay-related firing of prefrontal cortex neurons (as a result, behavioral inhibition may be affected); mechanism of action in ADHD is not known

            Absorption

            AUC: 56 ng·hr/mL (immediate release tablets); 32 ng·hr/mL (extended release tablets)

            Peak plasma concentration: 2.5 ng/mL (Immediate release tablets); 1 ng/mL (extended release tablets)

            Peak plasma time: 3 hr (immediate release tablets); 6 hr (extended release tablets)

            Bioavailability: 80-100% (immediate release tablets); 58% (extended release tablets)

            Onset: Initial effect (2 hr); maximum effect (6 hr)

            Duration: 24 hr

            Distribution

            Protein bound: 70%

            Vd: 6.3 L/kg

            Metabolism

            Via CYP3A4 (hepatic)

            Metabolites: Glucuronide and sulfate of 3-hydroxy guanfacine, oxidized mercapturic acid derivatives (inactive)

            Elimination

            Half-life: 16 hr (immediate release tablets); 18 hr (extended release tablets)

            Dialyzable: HD (No)

            Excretion: Urine 80% (unchanged)

            Previous
            Next:

            Administration

            Oral Administration

            Administer orally once a day

            Extended-release tablets

            • Do not administer with high-fat meals due to potential for increased serum levels
            • Swallow tablets whole; do not crush, chew, or break tablets because this will increase the rate of guanfacine release
            • Missed dose: Repeat dosage titration based on patient tolerability

            Storage

            Immediate-release tablets: at 20-25°C (68-77°F); dispense in a tight, light-resistant container

            Extended-release tablets: Store at 20-25°C (68-77°F); excursions permitted to 15-30°C (59-86°F)

            Previous
            Next:

            Images

            Previous
            Next:

            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
            • Manage and view all your plans together – even plans in different states.
            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
            Additional Offers
            Email to Patient

            From:

            To:

            The recipient will receive more details and instructions to access this offer.

            By clicking send, you acknowledge that you have permission to email the recipient with this information.

            Email Forms to Patient

            From:

            To:

            The recipient will receive more details and instructions to access this offer.

            By clicking send, you acknowledge that you have permission to email the recipient with this information.

            Previous
            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.