What to know about guanfacine for the treatment of ADHD
Treatment for ADHD typically involves a combination of behavioral therapy and stimulant medications. However, doctors sometimes also prescribe nonstimulant medications, such as guanfacine.
Attention deficit and hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that typically develops in children but can also occur in adults.
According to the Centers for Disease Control and Prevention (CDC), in the United States, doctors had diagnosed about 6.1 million children with ADHD by 2016. The CDC also reports that 62% of these children were taking medications to treat their symptoms that year.
Doctors typically prescribe stimulant medications, such as methylphenidate (Ritalin), for people with ADHD. However, they may recommend trying a nonstimulant drug if other medications are ineffective or cause unwanted side effects.
Other reasons why they might try to avoid prescribing stimulant medications include a history of substance use disorder or the concern that this may occur in the future.
In this article, we discuss the use and effectiveness of guanfacine for the treatment of ADHD. We also cover dosage and side effects, as well as risks and considerations.
What is guanfacine?
Guanfacine is a type of medication called an alpha-2A adrenergic receptor agonist. Doctors prescribe it under the brand name Tenex to help lower blood pressure in people with hypertension.
Guanfacine works by relaxing the blood vessels in the body, which improves blood flow and lowers a person’s heart rate and blood pressure.
Guanfacine also comes in the form of extended release tablets under the brand name Intuniv, which the Food and Drug Administration (FDA) has approved for the treatment of ADHD in children and adolescents aged 6–17 years.
Doctors may prescribe Intuniv by itself or in combination with other stimulant medications.
How does it work?
In addition to lowering blood pressure, guanfacine affects the prefrontal cortex, the area of the brain that controls impulsivity and attention span. However, guanfacine acts on the brain in a different way than stimulants.
Doctors usually recommend that people start at a low dosage and slowly build up to a safe and effective dosage to allow them to adjust to any side effects. Due to this approach, it may take a few weeks for a person to experience the full benefits of this treatment.
It is important to continue taking the medication as the doctor directs, even if the symptoms start to improve. People typically see an improvement in their ADHD symptoms within about 2 weeks of starting treatment, although some individuals may experience the benefit of the medication more quickly.
Is it effective?
According to a 2011 drug review, although guanfacine has approval for the short-term treatment of ADHD in children aged 6–17 years, it appears to be most effective in those up to the age of 12 years.
Research showed that children who took 1–4 milligrams (mg) of guanfacine had an average score decrease on the ADHD Rating Scale-IV of 17–21 points, compared with a reduction of 9–12 points in those who took a placebo.
However, these results were only statistically significant in children aged 6–12 years.
The ADHD Rating Scale-IV measures ADHD symptoms and behaviors, such as hyperactivity, impulsivity, and attention difficulties. A lower score indicates less severe symptoms.
The FDA has approved Intuniv only for the treatment of ADHD. Intuniv is available as 1-mg, 2-mg, 3-mg, and 4-mg extended release tablets. The extended release form has a slower absorption rate and longer half-life, which means that people do not need to take more than one dose per day and makes it more suitable for children.
The appropriate dosage of Intuniv depends on the child’s age, weight, symptoms, response to the medication, and tolerance of side effects.
When prescribing Intuniv, the doctor will typically begin with the lowest dosage and then gradually increase this until the child’s symptoms are under control.
The manufacturer recommends starting at a dosage of 1 mg per day and increasing this incrementally by no more than 1 mg per week. The maximum recommended dosage is 4 mg per day.
As Intuniv is an extended release tablet, it is important never to crush or chew the pill. The child should swallow the tablet whole with a glass of water.
It is also important to take the pill at the same time every day, such as in the morning or evening, even on weekends and holidays. Missing doses may cause unpleasant side effects.
If a child misses two or more doses, the doctor may suggest restarting at the original 1-mg-per-day dosage and gradually increasing this to reach their regular dosage.
Stopping the medication abruptly can also cause potentially dangerous side effects, including transient hypertension. The manufacturer advises slowly reducing the dosage by 1 mg every 3–7 days.
As with all medications, guanfacine can cause side effects. The most common side effects include:
- sedation, which is dose-dependent and temporary
Other side effects, many of which are dose-dependent, include:
- low blood pressure
- abdominal pain
- decreased appetite
- dry mouth
It is important to discuss any unpleasant or concerning side effects with a doctor, who may recommend lowering the dosage or switching to an alternative treatment.
Risks and considerations
Guanfacine may not be suitable for children with liver or kidney problems or those with a history of cardiovascular issues, such as low blood pressure or heart disease.
Doctors may regularly monitor the blood pressure and pulse of some children taking guanfacine to make sure that everything is normal.
Guanfacine can interact with some other medications, including:
- ketoconazole (Nizoral)
- clonidine (Catapres)
- rifampin (Rifadin)
- carbamazepine (Tegretol)
- phenytoin (Dilantin)
- valproic acid (Depakote)
Guanfacine can also interact with antihypertensive medications, potentially causing low blood pressure or fainting. Also, guanfacine may interact with alcohol or depressant medications — including benzodiazepines, barbiturates, and antipsychotics — leading to an increased sedative effect.
Parents or caregivers can minimize the risk of drug interactions with guanfacine by informing the doctor about any medications or supplements that the child is currently taking.
Guanfacine is a nonstimulant drug option for the treatment of children with ADHD. A doctor may prescribe guanfacine if stimulant medications have proven ineffective or if parents or caregivers are concerned that they will cause harmful or unpleasant side effects.
It is vital that children take guanfacine as the doctor directs to maximize its effectiveness and reduce the risk of side effects. Parents or caregivers should discuss any side effects or other concerns with the child’s doctor.
Category: adhd awareness