Guanfacine: Uses, Dosage, and How It Works

What Is Guanfacine?

Guanfacine is a non-stimulant drug used for the treatment of attention-deficit hyperactivity disorder (ADHD) in people between the ages of six and 17 years. Guanfacine is used to treat high blood pressure in children and adults. Guanfacine tablets should be taken once or twice a day. Guanfacine may be taken with or without food. However, Guanfacine may be taken with a high-fat meal to increase its absorption. If you change the brand, strength, or form of this medication, you may need to adjust your dosage. Use only the medication in the form and strength your doctor prescribed to prevent medication errors.

What Is Guanfacine Used For?

1. Hypertension - Guanfacine is used to treat high blood pressure (hypertension). High blood pressure increases the work that the heart and arteries do. If this problem is allowed to continue, the heart and arteries may not work properly. This may result in a stroke, heart failure, or kidney failure due to issues with the blood vessels around the brain, heart, and kidneys. Heart attacks can also be made more likely by high blood pressure. These problems can be prevented or reduced if blood pressure can be controlled.

It acts by regulating the nerve impulses traveling through some nerve pathways.  As a result, the blood vessels relax, making it easier for blood to pass through them. This resulted in a decrease in blood pressure.

2. Attention Deficit Hyperactivity Disorder - Guanfacine extended-release tablets can also be used alone or in conjunction with other drugs to treat children and teenagers with attention deficit hyperactivity disorder (ADHD). It helps children and adults with ADHD who are overactive, have trouble focusing for extended periods of time, or are easily distracted and impulsive by improving attention and reducing restlessness. This medication is used in conjunction with social, educational, and psychological therapies as part of a comprehensive treatment plan.

When Should You Take Guanfacine?

You should always swallow extended-release tablets whole and avoid high-fat meals because timing and form greatly affect absorption and side effects. You should take Guanfacine at the same time every day, usually at bedtime, to help with sleepiness, but you can take it morning or night, depending on your doctor's advice and how it affects you. 

How Does Guanfacine Work? 

Guanfacine has been found to stimulate alpha-2A adrenergic receptors in the nervous system and the brain. This receptor has been found to react to norepinephrine, a chemical in the nervous system, which controls the rate of heartbeat and blood pressure. The stimulation of this alpha-2A receptor has been found to slow the heart rate and lower the blood pressure since the sympathetic nervous system, also known as the fight or flight response, is calmed.

Guanfacine has been shown to decrease cyclic adenosine monophosphate activity in nerve cells, which stabilizes electrical activity in brain regions that regulate behavior, planning, and attention. This helps to calm the nervous system, reducing impulsiveness, distractibility, and behavioral overactivity, which is important for those suffering from attention deficit hyperactivity disorder.

Dosage and Administration

Available Dosage Forms

• An oral tablet that releases right away.

• Oral tablet with extended release.

Common strengths:

• 1 mg (milligrams).

• 2 mg.

• 3 mg (long-acting).

• 4 mg (long-acting).

You can only get Guanfacine in tablet form for oral use, and there are both short-acting and long-acting versions.

Adult Dosage      

For high blood pressure:

• The first dose is one milligram once a day, usually at bedtime.

•  If necessary, the dose can be slowly raised.

• The usual dose for maintenance is one to three milligrams once a day.

A doctor should always help you change your dose, especially if you have liver or kidney problems.

Children's Dosage for Guanfacine

For attention-deficit hyperactivity disorder:

• First Dose: one milligram once a day.

• The dose may go up by one milligram a week, depending on how well the patient responds and how well they can handle it.

• The usual dose range is one to four milligrams once a day.

• The most you can take in a day is four milligrams.

The dose may be adjusted based on how much you weigh. It would be best to take your tablet whole and avoid crushing or chewing it.

Missed Dose

• If a dose of the drug is missed, the missed dose should be taken as soon as the person remembers.

• However, the missed dose should be skipped if the time to take the next dose is almost near.

• It should not be taken twice the dose to compensate for the missed dose.

• In case a person misses more than one dose, they should seek the advice of a doctor because the dose should be slowly increased.

Overdose

• Symptoms of overdosing on the drug include excessive sleepiness, dizziness, low blood pressure, slow heart rate, weakness, and even fainting.

• Severe overdosing symptoms affect the breathing rate and the level of alertness.

What Are the Side Effects of Guanfacine?

Common Side Effects:

• Dry mouth.

• Tiredness and weakness.

• Headache.

• Less sexual ability.

• Less appetite.

• Pain in the stomach.

Serious Side Effects:

• Fainting.

• Blurred vision.

• Rash.

• Slow heart rate.

Warnings and Precautions

Who Should Not Take Guanfacine?

• People allergic to Guanfacine or its ingredients.

• People with a history of severe low blood pressure.

• People with a very slow heart rate or heart rhythm problems, except when advised by a doctor.

• People with fainting spells that result from low blood pressure.

• People with severe liver disease should not be treated except when under close monitoring.

Guanfacine should be taken with caution by people with heart disease, kidney disease, and a history of depression. Before taking the medication, go over your whole medical history with your doctor.

What Should You Know Before Taking Guanfacine?

• Inform your doctor if you are suffering from heart conditions, low blood pressure, a slow heart rate, or a history of fainting spells.

• Inform your doctor if you are suffering from any liver or kidney disorders.

• Inform your doctor if you are taking other medications that cause drowsiness or low blood pressure.

• Alcohol must be avoided as it increases drowsiness and lowers blood pressure.

• The medicine must not be stopped suddenly, as this increases blood pressure.

• The dosage must be reduced gradually.

• The drug must not be taken if you are pregnant or breastfeeding.

What Interactions Can Occur With Guanfacine?

Drug Interactions

• Other blood pressure medicines may increase the risk of low blood pressure or dizziness.

• Heart rate-slowing medicines increase the risk of bradycardia.

• Sedatives, sleeping aids, anti-anxiety agents, or alcohol increase the risk of drowsiness.

• Certain types of antidepressant or antipsychotic medicines may increase the effects of Guanfacine.

• Potent liver enzyme inhibitors or inducers have a potential impact on Guanfacine levels in the body.

You must tell your doctor about all prescription and over-the-counter medicines and supplements you are taking.

Food Interaction

• Guanfacine can be taken with or without food. However, it is best to take the drug the same way each time. 

• A high-fat meal may increase the absorption of the extended-release formulation. 

• Avoid alcohol because it makes dizziness and drowsiness worse.

Guanfacine Use During Pregnancy and Breastfeeding

Is Guanfacine Safe During Pregnancy?

There are no sufficient studies of Guanfacine in pregnant women to determine whether it is safe for use during pregnancy. 

• The drug should be used during pregnancy only if the benefits to the patient outweigh the risks to the unborn child.

• If you are pregnant, planning to become pregnant, or think that you may be pregnant, talk to your healthcare provider before taking the medicine.

• Do not stop taking Guanfacine suddenly, as it may lead to high blood pressure.

Can You Take Guanfacine While Breastfeeding?

• Caution is advised as there is limited information available.

• There is a possibility that the child may experience excessive sleepiness, lack of appetite, and low blood pressure.

• If the medicine is to be taken, it is possible that the child may have to be observed for unusual symptoms.

• There may be other alternative medicines that your health care provider may consider in some cases.

How Should You Store Guanfacine?

• Keep the tablets at room temperature, away from excess heat and moisture.

• Store the tablets in a dry place, away from the bathroom and the kitchen sink.

• Store the medicine in the original container with the lid tightly closed.

• Store the tablets away from direct light.

• Store the tablets out of the reach of children and pets.

• Do not use the tablets after the expiration date.

• Dispose of the tablets according to the local pharmacy waste disposal guidelines.

Conclusion

Guanfacine and Guanfacine extended-release tablets are used along with other drugs to treat high blood pressure. Guanfacine extended-release tablets, a long-acting form of Guanfacine, are part of a treatment program that helps control ADHD symptoms (more trouble focusing, controlling actions, and staying still or quiet than other people the same age) in children. Guanfacine belongs to a group of medicines called centrally acting alpha2-adrenergic receptor agonists. For detailed information and personalized advice, you can consult a medical specialist.

Key Takeaways

• Guanfacine is used to treat high blood pressure in adults and ADHD in children.

• Take Guanfacine precisely as prescribed by your doctor. Never adjust the dosage on your own.

• Do not discontinue the drug abruptly, as this may cause a sudden increase in blood pressure.

• Blood pressure and pulse rate should be regularly monitored. Sleepiness, tiredness, or dizziness may occur, especially during the initial stages of taking the drug.

• Alcohol must be avoided as it may increase the risk of side effects such as sleepiness.

• Regular follow-ups must be made with your doctor to adjust the dosage if necessary.