Guanfacine

GUANFACINE- guanfacine hydrochloride tablet, extended release
Bryant Ranch Prepack

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1 INDICATIONS AND USAGE

Guanfacine extended-release tablets are indicated for the treatment of Attention Deficit Hyperactivity Disorder (ADHD) as monotherapy and as adjunctive therapy to stimulant medications [see Clinical Studies (14)].

2 DOSAGE AND ADMINISTRATION

2.1 General Instruction for Use

Swallow tablets whole. Do not crush, chew, or break tablets because this will increase the rate of guanfacine release. Do not administer with high fat meals, due to increased exposure.

2.2 Dose Selection

Take guanfacine extended-release tablets orally once daily, either in the morning or evening, at approximately the same time each day. Begin at a dose of 1 mg/day, and adjust in increments of no more than 1 mg/week.

In monotherapy clinical trials, there was dose- and exposure-related clinical improvement as well as risks for several clinically significant adverse reactions (hypotension, bradycardia, sedative events). To balance the exposure-related potential benefits and risks, the recommended target dose range depending on clinical response and tolerability for guanfacine extended-release tablets is 0.05 to 0.12 mg/kg/day (total daily dose between 1 to 7 mg) (See Table 1).

Table 1: Recommended Target Dose Range for Therapy with guanfacine extended-release tablets

Weight

Target dose range (0.05 to 0.12 mg/kg/day)

25 to 33.9 kg

2 to 3 mg/day

34 to 41.4 kg

2 to 4 mg/day

41.5 to 49.4 kg

3 to 5 mg/day

49.5 to 58.4 kg

3 to 6 mg/day

58.5 to 91 kg

4 to 7 mg/day

>91 kg

5 to 7 mg/day

Doses above 4 mg/day have not been evaluated in children (ages 6 to 12 years) and doses above 7 mg/day have not been evaluated in adolescents (ages 13 to 17 years)

In the adjunctive trial which evaluated guanfacine extended-release tablets treatment with psychostimulants, the majority of patients reached optimal doses in the 0.05 to 0.12 mg/kg/day range. Doses above 4 mg/day have not been studied in adjunctive trials.

2.3 Switching from Immediate-Release Guanfacine to Guanfacine Extended-Release Tablets

If switching from immediate-release guanfacine, discontinue that treatment, and titrate with guanfacine extended-release tablets following above recommended schedule.

Do not substitute for immediate-release guanfacine tablets on a milligram-per-milligram basis, because of differing pharmacokinetic profiles. Guanfacine extended-release tablets has significantly reduced Cmax (60% lower), bioavailability (43% lower), and a delayed Tmax (3 hours later) compared to those of the same dose of immediate-release guanfacine [see Clinical Pharmacology (12.3)].

2.4 Maintenance Treatment

Pharmacological treatment of ADHD may be needed for extended periods. Healthcare providers should periodically re-evaluate the long-term use of guanfacine extended-release tablets, and adjust weight-based dosage as needed. The majority of children and adolescents reach optimal doses in the 0.05 to 0.12 mg/kg/day range. Doses above 4 mg/day have not been evaluated in children (ages 6-12 years) and above 7 mg/day have not been evaluated in adolescents (ages 13-17 years) [see Clinical Studies (14)].

2.5 Discontinuation of Treatment

Following discontinuation of guanfacine extended-release tablets, patients may experience increases in blood pressure and heart rate [see Warnings and Precautions (5.4) and Adverse Reactions (6)]. Patients/caregivers should be instructed not to discontinue guanfacine extended-release tablets without consulting their health care provider. Monitor blood pressure and pulse when reducing the dose or discontinuing the drug. Taper the daily dose in decrements of no more than 1 mg every 3 to 7 days to minimize the risk of rebound hypertension.

2.6 Missed Doses

When reinitiating patients to the previous maintenance dose after two or more missed consecutive doses, consider titration based on patient tolerability.

2.7 Dosage Adjustment with Concomitant Use of Strong and Moderate CYP3A4 Inhibitors or Inducers

Dosage adjustments for guanfacine extended-release tablets are recommended with concomitant use of strong and moderate CYP3A4 inhibitors (e.g., ketoconazole), or CYP3A4 inducers (e.g., carbamazepine) (Table 2) [see Drug Interactions (7)].

Table 2: Guanfacine Extended-Release Tablets Dosage Adjustments for Patients Taking Concomitant CYP3A4 Inhibitors or Inducers

Clinical Scenarios

Starting guanfacine extended-release tablets while currently on a CYP3A4 modulator

Continuing guanfacine extended-release tablets while adding a CYP3A4 modulator

Continuing guanfacine extended-release tablets while stopping a CYP3A4 modulator

CYP3A4 Strong and moderate Inhibitors

Decrease guanfacine extended-release tablets dosage to half the recommended level. (see Table 1)

Decrease guanfacine extended-release tablets dosage to half the recommended level. (see Table 1)

Increase guanfacine extended-release tablets dosage to recommended level. (see Table 1)

CYP3A4 Strong and moderate Inducers

Consider increasing guanfacine extended-release tablets dosage up to double the recommended level. (see Table 1)

Consider increasing guanfacine extended-release tablets dosage up to double the recommended level over 1 to 2 weeks. (see Table 1)

Decrease guanfacine extended-release tablets dosage to recommended level over 1 to 2 weeks. (see Table 1)

3 DOSAGE FORMS AND STRENGTHS

1 mg, 2 mg, 3 mg and 4 mg extended-release tablets

4 CONTRAINDICATIONS

Guanfacine is contraindicated in patients with a history of a hypersensitivity reaction to guanfacine extended-release tablets or its inactive ingredients, or other products containing guanfacine. Rash and pruritus have been reported.

5 WARNINGS AND PRECAUTIONS

5.1 Hypotension, Bradycardia, and Syncope

Treatment with guanfacine extended-release tablets 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 guanfacine 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.

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