Guanfacine (medication): what it is, and characteristics of this drug.

Guanfacine is used in some cases of children with adhd and high blood pressure.

Guanfacine is an antihypertensive drug used for the treatment of ADHD (Attention Deficit Hyperactivity Disorder) and for cases of arterial hypertension. It is a selective adrenergic receptor agonist.

In this article we will learn about the characteristics of this drug (format, administration, mechanism of action...), its indications, adverse effects, studies and precautions to be taken into account for its use.

Guanfacine: general characteristics.

Guanfacine is an antihypertensive drug, with the trade name "Intuniv". At the chemical level, it is derived from phenylacetylguanidine. Its mechanism of action is based on selective adrenergic (adrenaline) agonism for alpha 2A (α2A) receptors.

The effects of guanfacine are to lower blood pressure. How does it do this? By activating the receptors found in the brainstem and inhibiting the activity of the sympathetic system (this system is part of the Autonomic Nervous System (ANS) and is related to the activation and preparation of the organism to fight).

All this translates into a reduction of the nervous impulses of the heart and blood vessels; that is to say, what guanfacine does is to relax the latter, also reducing blood pressure and improving blood flow.

Mechanism of action.

Thus, the mechanism of action of guanfacine consists, as we were saying, in producing a selective agonist effect on alpha 2A-adrenergic receptors..

In the case of guanfacine administration for Attention Deficit Hyperactivity Disorder (ADHD), which we will see below, the exact mechanism that produces the therapeutic effects is unknown; however, preclinical studies suggest actions in the prefrontal cortex and in the basal ganglia. These actions are related to the intervention on noradrenaline in the receptors already mentioned.

Administration

Guanfacine is administered orally (in tablet form).. Generally, its recommended initial dose is once a day; ideally in the morning or in the evening. Guanfacine, like many other drugs, can be taken with or without food. On the other hand, one thing to note is that it is not recommended to take it with high-fat foods or grapefruit juice.

Its tablets are extended release, and correspond to the following amounts: 1 mg, 2 mg, 3 mg or 4 mg.

Indications

Guanfacine's indications include cases of arterial hypertension and Attention Deficit Hyperactivity Disorder (ADHD), and it has been authorized for both types of pathologies. In the case of arterial hypertension, guanfacine is generally used in combination with other drugs to reduce this tension.

On the other hand, in the case of ADHD, a series of specifications are established for the administration of guanfacine: it is to be used only in children and adolescents between the ages of 17 years and older.and in cases where stimulants have been used previously and have not provided good results, not being tolerated or proving ineffective.

In addition, in this second case, it should be used as part of a comprehensive treatment of ADHD that a comprehensive treatment of ADHD that also includes psychological treatment, educational and educational and social measures.

Considerations and precautions

The only contraindication to guanfacine is to manifest hypersensitivity to it. As for precautions, in cases of hepatic insufficiency it will sometimes be necessary to reduce its dose.

On the other hand, in relation to pregnancy and lactationIt is not advisable to take guanfacine when pregnant, nor if you are a woman of childbearing age and are not using any contraceptive method.

It is not known exactly whether guanfacine (or its metabolites) is excreted in breast milk during lactation, but animal studies suggest that it is. Thus, lactating women should evaluate the risks and benefits in their case, and assess the best option (either discontinue breastfeeding or discontinue guanfacine treatment).

Another aspect to bear in mind is that we should not suddenly stop taking guanfacine, as this could cause a rise in blood pressure. Finally, you should avoid taking guanfacine when you have to driveFinally, you should avoid taking guanfacine when you have to drive, or when you have to do any task that requires a high level of alertness.

Use in ADHD

The pharmacological treatment typically used for Attention Deficit Hyperactivity Disorder (ADHD) is stimulants. However, guanfacine has also been used for these cases, although it is not a stimulant. The exact mechanism of action of guanfacine in ADHD is not known, but it is known that it interacts with the brain areas of the brain that are involved in ADHD. it interacts with the brain areas involved in attention and impulses..

Specifically, delayed-release (or extended-release) guanfacine has been used for this purpose, proving to be an effective and well-tolerated treatment option for patients. In fact, it is approved by the FDA for children with ADHD over 6 years of age. The FDA is the U.S. government agency responsible for the regulation of drugs and other types of products (cosmetics, medical devices, biological products...).

1. Adverse effects in ADHD

The adverse effects encountered with the administration of guanfacine for ADHD have been, from most to least frequent: drowsiness, tiredness and/or fatigue (in 40% of the cases), headache (25%), and abdominal pain (less frequent, only in 10% of cases).

On the other hand, the symptom of drowsiness improves when delayed-release guanfacine is administered in conjunction with some type of stimulants, such as methylphenidate (trade name: rubifen, medikinet or concerta) or lisdexamfetamine (elvanse). Thus, guanfacine associated with stimulants provides a better therapeutic response than guanfacine administered alone, since it alleviates the adverse effects of guanfacine.

2. Studies

Although guanfacine has been shown to be effective in some cases of ADHD, there is not enough research to know the effects of long-term extended-release guanfacine use (used for several years) in children aged 6 years and older. Therefore, caution should be exercised.

Side effects

Some of the adverse reactions produced by guanfacine are: sedation, dizziness, hypotension, nightmares, constipation, nausea, vomiting, diarrhea, emotional lability, anxiety, depression, reduced appetite or weight gain, and abdominal pain.decreased appetite or weight gain, and abdominal pain.

In addition, it is known that drinking alcohol while taking guanfacine can lead to an increase in some of these adverse reactions.

Regarding the adverse effects of guanfacine on the heart, we find: low blood pressure, slow heart rate and other heart rhythm disturbances. These effects are serious enough to require medical supervision (and follow-up).