What is the recommended dosing for Intuniv (guanfacine) when used in combination with Concerta (methylphenidate) in a child?

Dosing of Intuniv (Guanfacine) in Combination with Concerta (Methylphenidate) in Children

When using guanfacine extended-release (Intuniv) in combination with methylphenidate extended-release (Concerta) in children, start with Intuniv at 1 mg once daily and titrate by 1 mg weekly to a target dose range of 0.05-0.12 mg/kg/day or 1-7 mg/day, while maintaining the established effective dose of Concerta. 1

Guanfacine (Intuniv) Dosing Guidelines

Initial Dosing

• Start with 1 mg once daily
• Administer at the same time each day for consistent blood levels

Titration Schedule

• Increase by 1 mg weekly based on response and tolerability
• Target dose range: 0.05-0.12 mg/kg/day or 1-7 mg total daily dose
• Allow adequate time between dose adjustments to assess clinical response

Combination Therapy Considerations

• No significant pharmacokinetic interactions occur between guanfacine and methylphenidate when coadministered 2
• The combination does not require dose adjustments of either medication due to drug-drug interactions
• The 90% confidence intervals for maximum plasma concentration (Cmax) and area under the curve (AUC) values meet bioequivalence criteria when the medications are given together 2

Monitoring During Combination Therapy

Vital Signs

• Monitor blood pressure and pulse regularly
• Both medications can affect cardiovascular parameters
• Most changes in blood pressure, pulse rate, and ECG readings are modest and not clinically significant 3

Common Side Effects to Monitor

• Somnolence (50.7%)
• Headache (22.1%)
• Sedation (13.2%)
• Upper abdominal pain (11.8%)
• Fatigue (11.0%) 3

Important Considerations

• Sedation, somnolence, or hypersomnia occur in approximately 62.5% of children taking guanfacine
• These effects are most common during dose titration but typically resolve (63.5% of cases) prior to treatment completion 3
• No unique adverse events have been observed with coadministration compared to either medication alone 2

Clinical Efficacy of Combination Therapy

The combination of methylphenidate and guanfacine has shown benefits beyond monotherapy:

• Combined treatment has demonstrated significant improvements in spatial working memory tasks compared to either medication alone 4
• The combination may be particularly beneficial for children who have inadequate response to stimulant monotherapy
• Guanfacine can help address both ADHD symptoms and oppositional symptoms, with an effect size of 0.59 for oppositional symptoms and 0.92 for ADHD symptoms 3

Common Pitfalls to Avoid

1. Rapid Titration: Increasing guanfacine dose too quickly can lead to excessive sedation and hypotension
2. Abrupt Discontinuation: Always taper guanfacine gradually to avoid rebound hypertension
3. Overlooking Drug Interactions: While methylphenidate and guanfacine don't significantly interact pharmacokinetically, be cautious with other medications that affect blood pressure
4. Ignoring Weight-Based Dosing: Children may require different doses based on body weight (target 0.05-0.12 mg/kg/day)
5. Missing Side Effect Patterns: Sedation typically peaks during titration and often improves with continued treatment

By following these dosing guidelines and monitoring parameters, the combination of Intuniv and Concerta can be safely and effectively administered to children with ADHD who require combination therapy.