Guanfacine

GUANFACINE- guanfacine hydrochloride tablet, extended release
AvKARE, Inc.

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 is 0.05 to 0.12 mg/kg/day (total daily dose between 1 mg to 4 mg).

In the adjunctive trial which evaluated guanfacine extended-release 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.

Additional pediatric use information for patients ages 6 to 17 years is approved for Shire US Inc.’s INTUNIV ® (guanfacine) extended-release tablet product. However, due to Shire US Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.

2.3 Switching from Immediate-Release Guanfacine to Guanfacine E xtended- R elease

If switching from immediate-release guanfacine, discontinue that treatment, and titrate with guanfacine extended-release 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 has significantly reduced C max (60% lower), bioavailability (43% lower), and a delayed T max (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, 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.

Additional pediatric use information for patients ages 6 to 17 years is approved for Shire US Inc.’s INTUNIV ® (guanfacine) extended-release tablet product. However, due to Shire US Inc.’s marketing exclusivity rights, this drug product is not labeled with that pediatric information.

2.5 Discontinuation of Treatment

Following discontinuation of guanfacine extended-release, patients may experience increases in blood pressure and heart rate [see Warnings and Precautions (5.4) and Adverse Reaction s (6) ]. Patients/caregivers should be instructed not to discontinue guanfacine extended-release 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 avoid 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 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 Dosage Adjustments for Patients Taking Concomitant CYP3A4 Inhibitors or Inducers
Clinical Scenarios
Starting guanfacine extended-release while currently on a CYP3A4 modulator Continuing guanfacine extended- release while adding a CYP3A4 modulator Continuing guanfacine extended-release while stopping a CYP3A4 modulator
CYP3A4 Strong and M oderate Inhibitors Decrease guanfacine extended-release dosage to half the recommended level. Decrease guanfacine extended-release dosage to half the recommended level. Increase guanfacine extended-release dosage to recommended level.
CYP3A4 Strong and M oderate Inducers Consider increasing guanfacine extended- release dosage up to double the recommended level. Consider increasing guanfacine extended-release dosage up to double the recommended level over 1 to 2 weeks. Decrease guanfacine extended-release dosage to recommended level over 1 to 2 weeks.

3 DOSAGE FORMS AND STRENGTHS

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

4 CONTRAINDICATIONS

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

5 WARNINGS AND PRECAUTIONS

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