CYP3A4 metabolism. Minor/Significance Unknown.agrimonyagrimony increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.anastrozoleanastrozole will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.atenololatenolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.betaxololbetaxolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.bisoprololbisoprolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.brimonidinebrimonidine increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.celiprololceliprolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.chlorpropamideguanfacine decreases effects of chlorpropamide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, chlorpropamide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.cornsilkcornsilk increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.cyclophosphamidecyclophosphamide will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.esmololesmolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.forskolinforskolin increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.glimepirideguanfacine decreases effects of glimepiride by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, glimepiride. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.glipizideguanfacine decreases effects of glipizide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, glipizide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.glyburideguanfacine decreases effects of glyburide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, glyburide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.insulin aspartguanfacine decreases effects of insulin aspart by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, insulin aspart. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.insulin detemirguanfacine, insulin detemir. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.guanfacine decreases effects of insulin detemir by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.insulin glargineguanfacine, insulin glargine. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.guanfacine decreases effects of insulin glargine by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.insulin glulisineguanfacine, insulin glulisine. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.guanfacine decreases effects of insulin glulisine by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.insulin lisproguanfacine decreases effects of insulin lispro by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, insulin lispro. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.insulin NPHguanfacine, insulin NPH. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.guanfacine decreases effects of insulin NPH by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.insulin regular humanguanfacine decreases effects of insulin regular human by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, insulin regular human. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.larotrectiniblarotrectinib will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.maitakemaitake increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.metforminguanfacine decreases effects of metformin by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, metformin. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.metoprololmetoprolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.miglitolguanfacine decreases effects of miglitol by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, miglitol. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.nateglinideguanfacine decreases effects of nateglinide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, nateglinide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.nebivololnebivolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.octacosanoloctacosanol increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.penbutololpenbutolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.pioglitazoneguanfacine decreases effects of pioglitazone by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, pioglitazone. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.reishireishi increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.repaglinideguanfacine decreases effects of repaglinide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, repaglinide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.rosiglitazoneguanfacine decreases effects of rosiglitazone by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, rosiglitazone. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.saxagliptinguanfacine decreases effects of saxagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, saxagliptin. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.shepherd's purseshepherd's purse, guanfacine. Other (see comment). Minor/Significance Unknown. Comment: Theoretically, shepherd's purse may interfere with BP control.sitagliptinguanfacine decreases effects of sitagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, sitagliptin. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.sotalolsotalol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.tizanidinetizanidine increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown. Risk of hypotension.tolazamideguanfacine decreases effects of tolazamide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, tolazamide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.tolbutamideguanfacine decreases effects of tolbutamide by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, tolbutamide. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.treprostiniltreprostinil increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.vildagliptinguanfacine decreases effects of vildagliptin by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia.guanfacine, vildagliptin. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.abametapirSerious - Use Alternative (1)abametapir 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.acarboseMinor (2)guanfacine decreases effects of acarbose by pharmacodynamic antagonism. Minor/Significance Unknown. Diminished symptoms of hypoglycemia. guanfacine, acarbose. Other (see comment). Minor/Significance Unknown. Comment: Decreased symptoms of hypoglycemia. Mechanism: decreased hypoglycemia induced catecholamine production.acebutololMinor (1)acebutolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.acetazolamideMinor (1)acetazolamide will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.acrivastineMonitor Closely (1)acrivastine and guanfacine both increase sedation. Use Caution/Monitor.agrimonyMinor (1)agrimony increases effects of guanfacine by pharmacodynamic synergism. Minor/Significance Unknown.aldesleukinMonitor Closely (1)aldesleukin increases effects of guanfacine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.amifostineMonitor Closely (1)amifostine, 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.amiodaroneMonitor Closely (1)amiodarone 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.amisulprideMonitor Closely (1)amisulpride and guanfacine both increase sedation. Use Caution/Monitor.amitriptylineSerious - Use Alternative (1)amitriptyline decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.amobarbitalMonitor Closely (1)amobarbital 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.amoxapineSerious - Use Alternative (1)amoxapine decreases effects of guanfacine by Other (see comment). Avoid or Use Alternate Drug. Comment: Inhibition of uptake by adrenergic neurons.anastrozoleMinor (1)anastrozole will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apalutamideSerious - Use Alternative (1)apalutamide 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.aprepitantMonitor Closely (1)aprepitant 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. aripiprazoleMonitor Closely (1)guanfacine, aripiprazole. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.armodafinilMonitor Closely (1)armodafinil 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.artemether/lumefantrineMonitor Closely (1)artemether/lumefantrine will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.asenapineMonitor Closely (1)asenapine and guanfacine both increase sedation. Use Caution/Monitor.asenapine transdermalMonitor Closely (1)asenapine transdermal and guanfacine both increase sedation. Use Caution/Monitor.atazanavirMonitor Closely (1)atazanavir 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. atenololMinor (1)atenolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.avanafilMonitor Closely (1)avanafil increases effects of guanfacine by pharmacodynamic synergism. Use Caution/Monitor. Risk of hypotension.avapritinibMonitor Closely (1)avapritinib and guanfacine both increase sedation. Use Caution/Monitor.belzutifanMonitor Closely (1)belzutifan will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information. benperidolMonitor Closely (1)guanfacine, benperidol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.benzhydrocodone/acetaminophenMonitor Closely (1)benzhydrocodone/acetaminophen and guanfacine both increase sedation. Use Caution/Monitor.betaxololMinor (1)betaxolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.bicalutamideMonitor Closely (1)bicalutamide 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.bisoprololMinor (1)bisoprolol, guanfacine. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Selective beta blocker administration during withdrawal from centrally acting alpha agonists may result in rebound hypertension.bosentanMonitor Closely (1)bosentan 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