Guanfacine

INTUNIV ® is indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) as monotherapy and as adjunctive therapy to stimulant medications [see Clinical Studies (14) ]. INTUNIV is a central alpha 2A -adrenergic receptor agonist indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) as monotherapy and as adjunctive therapy to stimulant medications ( 1 , 14 ).

1 mg, 2 mg, 3 mg, and 4 mg extended-release tablets Extended-release tablets: 1 mg, 2 mg, 3 mg, and 4 mg ( 3 )

INTUNIV is contraindicated in patients with a history of a hypersensitivity reaction to INTUNIV or its inactive ingredients, or other products containing guanfacine. Rash and pruritus have been reported. History of hypersensitivity to INTUNIV , its inactive ingredients, or other products containing guanfacine ( 4 ).

Hypotension, bradycardia, syncope: Titrate slowly and monitor vital signs frequently in patients at risk for hypotension, heart block, bradycardia, syncope, cardiovascular disease, vascular disease, cerebrovascular disease or chronic renal failure. Measure heart rate and blood pressure prior to initiation of therapy, following dose increases, and periodically while on therapy. Avoid concomitant use of drugs with additive effects unless clinically indicated. Advise patients to avoid becoming dehydrated or overheated ( 5.1 ). Sedation and somnolence: Occur commonly with INTUNIV . Consider the potential for additive sedative effects with CNS depressant drugs. Caution patients against operating heavy equipment or driving until they know how they respond to INTUNIV ( 5.2 ). Cardiac Conduction Abnormalities: May worsen sinus node dysfunction and atrioventricular (AV) block, especially in patients taking other sympatholytic drugs. Titrate slowly and monitor vital signs frequently ( 5.3 ). Rebound Hypertension: Abrupt discontinuation of INTUNIV can lead to clinically significant and persistent rebound hypertension. Subsequent hypertensive encephalopathy was also reported. To minimize the risk of rebound hypertension upon discontinuation, the total daily dose of INTUNIV should be tapered in decrements of no more than 1 mg every 3 to 7 days ( 5.4 ).

5.1 Hypotension, Bradycardia, and Syncope Treatment with INTUNIV can cause dose-dependent decreases in blood pressure and heart rate. Decreases were less pronounced over time of treatment. Orthostatic hypotension and syncope have been reported [see Adverse Reactions (6.1) ] . Measure heart rate and blood pressure prior to initiation of therapy, following dose increases, and periodically while on therapy. Titrate INTUNIV slowly in patients with a history of hypotension, and those with underlying conditions that may be worsened by hypotension and bradycardia; e.g., heart block, bradycardia, cardiovascular disease, vascular disease, cerebrovascular disease, or chronic renal failure. In patients who have a history of syncope or may have a condition that predisposes them to syncope, such as hypotension, orthostatic hypotension, bradycardia, or dehydration, advise patients to avoid becoming dehydrated or overheated. Monitor blood pressure and heart rate, and adjust dosages accordingly in patients treated concomitantly with antihypertensives or other drugs that can reduce blood pressure or heart rate or increase the risk of syncope.

5.2 Sedation and Somnolence Somnolence and sedation were commonly reported adverse reactions in clinical studies [see Adverse Reactions (6.1) ] . Before using INTUNIV with other centrally active depressants, consider the potential for additive sedative effects. Caution patients against operating heavy equipment or driving until they know how they respond to treatment with INTUNIV . Advise patients to avoid use with alcohol.

5.3 Cardiac Conduction Abnormalities The sympatholytic action of INTUNIV may worsen sinus node dysfunction and atrioventricular (AV) block, especially in patients taking other sympatholytic drugs. Titrate INTUNIV slowly and monitor vital signs frequently in patients with cardiac conduction abnormalities or patients concomitantly treated with other sympatholytic drugs.

5.4 Rebound Hypertension In post marketing experience, abrupt discontinuation of INTUNIV has resulted in clinically significant and persistent rebound hypertension above baseline levels and increases in heart rate. Hypertensive encephalopathy has also been reported in association with rebound hypertension with both INTUNIV and immediate release guanfacine [see Adverse Reactions (6.2) ] . In these cases, high-dosage guanfacine was discontinued; concomitant stimulant use was also reported, which may potentially increase hypertensive response upon abrupt discontinuation of guanfacine. Children commonly have gastrointestinal illnesses that lead to vomiting, and a resulting inability to take medications, so they may be especially at risk for rebound hypertension. To minimize the risk of rebound hypertension upon discontinuation, the total daily dose of INTUNIV should be tapered in decrements of no more than 1 mg every 3 to 7 days [see Dosage and Administration (2.5) ] . Blood pressure and heart rate should be monitored when reducing the dose or discontinuing INTUNIV. If abrupt discontinuation occurs (especially with concomitant stimulant use), patients should be closely followed for rebound hypertension.

The following serious adverse reactions are described elsewhere in the labeling: Hypotension, bradycardia, and syncope [see Warnings and Precautions (5.1) ] Sedation and somnolence [see Warnings and Precautions (5.2) ] Cardiac conduction abnormalities [see Warnings and Precautions (5.3) ] Rebound Hypertension [see Warnings and Precautions (5.4) ] Most common adverse reactions (≥5% and at least twice placebo rate) in fixed-dose monotherapy ADHD trials in children and adolescents (6 to 17 years): hypotension, somnolence, fatigue, nausea, and lethargy ( 6.1 ) Flexible dose-optimization ADHD trials in children (6 to 12 years) and adolescents (13 to 17 years): somnolence, hypotension, abdominal pain, insomnia, fatigue, dizziness, dry mouth, irritability, nausea, vomiting, and bradycardia ( 6.1 ). Adjunctive treatment to psychostimulant ADHD trial in children and adolescents (6 to 17 years): somnolence, fatigue, insomnia, dizziness, and abdominal pain ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Takeda Pharmaceuticals at 1-877-TAKEDA-7 (1-877-825-3327) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The data described below reflect clinical trial exposure to INTUNIV in 2,825 patients. This includes 2,330 patients from completed studies in children and adolescents, ages 6 to 17 years and 495 patients in completed studies in adult healthy volunteers. The mean duration of exposure of 446 patients that previously participated in two 2-year, open-label long-term studies was approximately 10 months. Fixed Dose Trials Table 3: Percentage of Patients Experiencing Most Common (≥5% and at least twice the rate for placebo) Adverse Reactions in Fixed Dose Studies 1 and 2 INTUNIV (mg) Adverse Reaction Term Placebo (N=149) 1 mg The lowest dose of 1 mg used in Study 2 was not randomized to patients weighing more than 50 kg. (N=61) 2 mg (N=150) 3 mg (N=151) 4 mg (N=151) All Doses of INTUNIV (N=513) Somnolence The somnolence term includes somnolence, sedation, and hypersomnia. 11% 28% 30% 38% 51% 38% Fatigue 3% 10% 13% 17% 15% 14% Hypotension The hypotension term includes hypotension, diastolic hypotension, orthostatic hypotension, blood pressure decreased, blood pressure diastolic decreased, blood pressure systolic decreased). 3% 8% 5% 7% 8% 7% Dizziness 4% 5% 3% 7% 10% 6% Lethargy 3% 2% 3% 8% 7% 6% Nausea 2% 7% 5% 5% 6% 6% Dry mouth 1% 0% 1% 6% 7% 4% Table 4: Adverse Reactions Leading to Discontinuation (≥2% for all doses of INTUNIV and >rate than in placebo) in Fixed Dose Studies 1 and 2 INTUNIV (mg) Adverse Reaction Term Placebo (N=149) 1 mg The lowest dose of 1 mg used in Study 2 was not randomized to patients weighing more than 50 kg. (N=61) 2 mg (N=150) 3 mg (N=151) 4 mg (N=151) All Doses of INTUNIV (N=513) n (%) n (%) n (%) n (%) n (%) n (%) Adverse reactions leading to discontinuation in ≥2% in any dose group but did not meet this criteria in all doses combined: hypotension (hypotension, diastolic hypotension, orthostatic hypotension, blood pressure decreased, blood pressure diastolic decreased, blood pressure systolic decreased), headache, and dizziness. Total patients 4 (3%) 2 (3%) 10 (7%) 15 (10%) 27 (18%) 54 (11%) Somnolence The somnolence term includes somnolence, sedation, and hypersomnia. 1 (1%) 2 (3%) 5 (3%) 6 (4%) 17 (11%) 30 (6%) Fatigue 0 (0%) 0 (0%) 2 (1%) 2 (1%) 4 (3%) 8 (2%) Table 5: Other Common Adverse Reactions (≥2% for all doses of INTUNIV and >rate than in placebo) in Fixed Dose Studies 1 and 2 INTUNIV (mg) Adverse Reaction Term Placebo (N=149) 1 mg The lowest dose of 1 mg used in Study 2 was not randomized to patients weighing more than 50 kg. (N=61) 2 mg (N=150) 3 mg (N=151) 4 mg (N=151) All Doses of INTUNIV (N=513) Adverse reactions ≥2% for all doses of INTUNIV and >rate in placebo in any dose group but did not meet this criteria in all doses combined: insomnia (insomnia, initial insomnia, middle insomnia, terminal insomnia, sleep disorder), vomiting, diarrhea, abdominal/stomach discomfort (abdominal discomfort, epigastric discomfort, stomach discomfort), rash (rash, rash generalized, rash papular), dyspepsia, increased weight, bradycardia (bradycardia, sinus bradycardia), asthma (asthma, bronchospasm, wheezing), agitation, anxiety (anxiety, nervousness), sinus arrhythmia, blood pressure increased (blood pressure increased, blood pressure diastolic increased), and first degree atrioventricular block. Headache 19% 26% 25% 16% 28% 23% Abdominal Pain The abdominal pain term includes abdominal pain, abdominal pain lower, abdominal pain upper, and abdominal tenderness. 9% 10% 7% 11% 15% 11% Decreased Appetite 4% 5% 4% 9% 6% 6% Irritability 4% 5% 8% 3% 7% 6% Constipation 1% 2% 2% 3% 4% 3% Nightmare The nightmare term includes abnormal dreams, nightmare, and sleep terror. 0% 0% 0% 3% 4% 2% Enuresis The enuresis term includes enuresis, nocturia, and urinary incontinence. 1% 0% 1% 3% 2% 2% Affect Lability The affect lability term includes affect lability and mood swings. 1% 2% 1% 3% 1% 2% Monotherapy Flexible Dose Trials Table 6: Percentage of Patients Experiencing Most Common (≥5% and at least twice the rate for placebo) Adverse Reactions in the Monotherapy Flexible Dose Study 4 INTUNIV Adverse Reaction Term Placebo (N=112) AM (N=107) PM (N=114) All Doses of INTUNIV (N=221) Somnolence The somnolence term includes somnolence, sedation, and hypersomnia. 15% 57% 54% 56% Abdominal Pain The abdominal pain term includes abdominal pain, abdominal pain lower, abdominal pain upper, and abdominal tenderness 7% 8% 19% 14% Fatigue 3% 10% 11% 11% Irritability 3% 7% 7% 7% Nausea 1% 6% 5% 5% Dizziness 3% 6% 4% 5% Vomiting 2% 7% 4% 5% Hypotension The hypotension term includes hypotension, diastolic hypotension, orthostatic hypotension, blood pressure decreased, blood pressure diastolic decreased, blood pressure systolic decreased). 0% 6% 4% 5% Decreased Appetite 3% 6% 3% 4% Enuresis The enuresis term includes enuresis, nocturia, and urinary incontinence. 1% 2% 5% 4% Table 7: Adverse Reactions Leading to Discontinuation (≥2% for all doses of INTUNIV and >rate than in placebo) in Monotherapy Flexible Dose Study 4 INTUNIV Adverse Reaction Term Placebo (N=112) AM (N=107) PM (N=114) All Doses of INTUNIV (N=221) n (%) n (%) n (%) n (%) Adverse reactions leading to discontinuation in ≥2% in any dose group but did not meet this criteria in all doses combined: fatigue Total patients 0 (0%) 8 (7%) 7 (6%) 15 (7%) Somnolence The somnolence term includes somnolence, sedation, and hypersomnia. 0 (0%) 4 (4%) 3 (3%) 7 (3%) Table 8: Other Common Adverse Reactions (≥2% for all doses of INTUNIV and >rate than in placebo) in the Monotherapy Flexible Dose Study 4 INTUNIV Adverse Reaction Term Placebo (N=112) AM (N=107) PM (N=114) All Doses of INTUNIV (N=221) Adverse reactions ≥2% for all doses of INTUNIV and >rate in placebo in any dose group but did not meet this criteria in all doses combined: affect lability (affect lability, mood swings), increased weight, syncope/loss of consciousness (loss of consciousness, presyncope, syncope), dyspepsia, tachycardia (tachycardia, sinus tachycardia), and bradycardia (bradycardia, sinus bradycardia). Headache 11% 18% 16% 17% Insomnia The insomnia term includes insomnia, initial insomnia, middle insomnia, terminal insomnia, and sleep disorder. […]

Table 14 contains clinically important drug interactions with INTUNIV [see Clinical Pharmacology (12.3) ]. Table 14: Clinically Important Drug Interactions: Effect of other Drugs on INTUNIV Concomitant Drug Name or Drug Class Clinical Rationale and Magnitude of Drug Interaction Clinical Recommendation Strong and moderate CYP3A4 inhibitors, e.g., ketoconazole, fluconazole Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in an increase in exposure Consider dose reduction [see Dosage and administration (2.7) ] Strong and moderate CYP3A4 inducers, e.g., rifampin, efavirenz Guanfacine is primarily metabolized by CYP3A4 and its plasma concentrations can be significantly affected resulting in a decrease in exposure Consider dose increase [see Dosage and administration (2.7) ] Strong and moderate CYP3A4 inhibitors increase guanfacine exposure. Decrease INTUNIV to 50% of target dosage when coadministered with strong and moderate CYP3A4 inhibitors ( 2.7 ). Strong and moderate CYP3A4 inducers decrease guanfacine exposure. Based on patient response, consider titrating INTUNIV dosage up to double the target dosage over 1 to 2 weeks ( 2.7 ).

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to ADHD medications, including INTUNIV, during pregnancy. Healthcare providers are encouraged to register patients by calling the National Pregnancy Registry for ADHD Medications at 1-866-961-2388. Risk Summary Available data with guanfacine over decades of use in pregnant women have not identified a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. However, use of guanfacine in pregnant women over this time has been infrequent. In animal reproduction studies, rabbits and rats exposed to 3 and 4 times the maximum recommended human dose (MRHD), respectively, showed no adverse outcomes. However, higher doses were associated with reduced fetal survival and maternal toxicity ( see Data ). The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data Reproduction studies conducted in rats have shown that guanfacine crosses the placenta. However, administration of guanfacine to rabbits and rats during organogenesis at 3 (rabbit) and 4 (rat) times the MRHD of 0.12 mg/kg/day on a mg/m 2 basis resulted in no evidence of harm to the fetus. Higher doses (13.5 times the MRHD in both rabbits and rats) were associated with reduced fetal survival and maternal toxicity.

8.2 Lactation Risk Summary There are no data on the presence of guanfacine in human milk or the effects on the breastfed infant. The effects on milk production are also unknown. Guanfacine is present in the milk of lactating rats (see Data ) . If a drug is present in animal milk, it is likely that the drug will be present in human milk. If an infant is exposed to guanfacine through breastmilk, monitor for symptoms of hypotension and bradycardia such as sedation, lethargy, and poor feeding (see Clinical Considerations ). The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for INTUNIV and any potential adverse effects on the breastfed child from INTUNIV or from the underlying maternal condition. Clinical Considerations Monitor breastfeeding infants exposed to guanfacine through breastmilk for sedation, lethargy, and poor feeding. Data Guanfacine was excreted in breast milk of lactating rats at a concentration comparable to that observed in blood, but slightly less than the concentration in plasma when administered following a single oral dose of 5 mg/kg. The concentration of drug in animal milk does not necessarily predict the concentration of drug in human milk.

8.4 Pediatric Use Safety and efficacy of INTUNIV in pediatric patients less than 6 years of age have not been established. The efficacy of INTUNIV was studied for the treatment of ADHD in five controlled monotherapy clinical trials (up to 15 weeks in duration), one randomized withdrawal study and one controlled adjunctive trial with psychostimulants (8 weeks in duration) in children and adolescents ages 6 to 17 who met DSM-IV ® criteria for ADHD [see Adverse Reactions (6) and Clinical Studies (14) ]. Animal Data In studies in juvenile rats, guanfacine alone produced a slight delay in sexual maturation in males and females at 2 to 3 times the maximum recommended human dose (MRHD). Guanfacine in combination with methylphenidate produced a slight delay in sexual maturation and decreased growth as measured by a decrease in bone length in males at a dose of guanfacine comparable to the MRHD and a dose of methylphenidate approximately 4 times the MRHD. In a study where juvenile rats were treated with guanfacine alone from 7 to 59 days of age, development was delayed as indicated by a slight delay in sexual maturation and decreased body weight gain in males at 2 mg/kg/day and in females at 3 mg/kg/day. The No Adverse Effect Level (NOAEL) for delayed sexual maturation was 1 mg/kg/day, which is equivalent to the MRHD of 4 mg/day, on a mg/m 2 basis. The effects on fertility were not evaluated in this study. In a study where juvenile rats were treated with guanfacine in combination with methylphenidate from 7 to 59 days of age, a decrease in ulna bone length and a slight delay in sexual maturation were observed in males given 1 mg/kg/day of guanfacine in combination with 50 mg/kg/day of methylphenidate. The NOAELs for these findings were 0.3 mg/kg of guanfacine in combination with 16 mg/kg/day of methylphenidate, which are equivalent to 0.3 and 1.4 times the MRHD of 4 mg/day and 54 mg/day for guanfacine and methylphenidate, respectively, on a mg/m 2 basis. These findings were not observed with guanfacine alone at 1 mg/kg/day or methylphenidate alone at 50 mg/kg/day.

8.5 Geriatric Use The safety and efficacy of INTUNIV in geriatric patients have not been established.

8.6 Renal Impairment It may be necessary to reduce the dosage in patients with significant impairment of renal function [see Clinical Pharmacology (12.3) ].

8.7 Hepatic Impairment It may be necessary to reduce the dosage in patients with significant impairment of hepatic function [see Clinical Pharmacology (12.3) ].

Guanfacine is a central alpha 2A -adrenergic receptor agonist. Guanfacine is not a central nervous system (CNS) stimulant. The mechanism of action of guanfacine in ADHD is not known.