AdultPediatricDosage Forms & Strengths tablet (Tenex) 1mg 2mg 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 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 Interaction CheckerEnter a drug name and guanfacineNo Results No Interactions Found Interactions FoundContraindicatedSerious - Use AlternativeSignificant - Monitor CloselyMinorAll Interactions Sort By: SeverityName Contraindicated (0)Serious - Use Alternative (30)abametapirabametapir will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.amitriptylineamitriptyline decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.amoxapineamoxapine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.apalutamideapalutamide will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.ceritinibceritinib will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.chloramphenicolchloramphenicol will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.clomipramineclomipramine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.cobicistatcobicistat will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.desipraminedesipramine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.doxepindoxepin decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.fexinidazolefexinidazole will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.imipramineimipramine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.iobenguane I 131guanfacine will decrease the level or effect of iobenguane I 131 by Other (see comment). Avoid or Use Alternate Drug. Based on the mechanism of action of iobenguane, drugs that reduce catecholamine uptake or that deplete catecholamine stores may interfere with iobenguane uptake into cells, and thus, reduce iobenguane efficacy. Discontinue interfering drugs for at least 5 half-lives before administration of either the dosimetry or an iobenguane dose. Do not administer these drugs until at least 7 days after each iobenguane dose.ivosidenibivosidenib will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.lofepraminelofepramine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.lofexidinelofexidine, guanfacine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that decrease pulse or blood pressure to mitigate risk of excessive bradycardia and hypotension.lorlatiniblorlatinib will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.maprotilinemaprotiline decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.metoclopramide intranasalguanfacine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.mifepristonemifepristone will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.mirtazapinemirtazapine decreases effects of guanfacine by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Risk of hypertensive urgency.nortriptylinenortriptyline decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.olopatadine intranasalguanfacine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. ponesimodponesimod, guanfacine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Consult cardiologist if considering treatment. Coadministration of ponesimod with drugs that decrease HR may have additive effects on decreasing HR and should generally not be initiated in these patients.protriptylineprotriptyline decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.ropeginterferon alfa 2bropeginterferon alfa 2b and guanfacine both increase Other (see comment). Avoid or Use Alternate Drug. Narcotics, hypnotics or sedatives can produce additive neuropsychiatric side effects. Avoid use and monitor patients receiving the combination for effects of excessive CNS toxicity.trazodonetrazodone decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.trimipraminetrimipramine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.tucatinibtucatinib will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.voxelotorvoxelotor will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.Monitor Closely (151)acrivastineacrivastine and guanfacine both increase sedation. Use Caution/Monitor.aldesleukinaldesleukin increases effects of guanfacine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.amifostineamifostine, guanfacine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration with blood pressure lowering agents may increase the risk and severity of hypotension associated with amifostine. When amifostine is used at chemotherapeutic doses, withhold blood pressure lowering medications for 24 hr prior to amifostine; if blood pressure lowering medication cannot be withheld, do not administer amifostine.amiodaroneamiodarone will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.amisulprideamisulpride and guanfacine both increase sedation. Use Caution/Monitor.amobarbitalamobarbital will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate 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.aprepitantaprepitant will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available. aripiprazoleguanfacine, aripiprazole. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.armodafinilarmodafinil will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inducers significantly reduce guanfacine plasma concentrations and elimination half-life. If coadministered, more frequent dosing of the IR product may