Trade names of clonidine are:
- Catapresan (A, D, CH)
- Haemiton (D)
- Isoglaucon (A, D)
- Paracefan (D)
Clonidine is a rather atypical medication for ADHD.
The stated effect size of 0.71 appears to be too high and due to an insufficient number of ascertaining studies
Clonidine is commonly used in autism spectrum disorders and may be helpful in comorbid ASD + ADHD in young children.
1. Mechanisms of action of clonidine
Clonidine is an alpha 2-adrenoceptor agonist.
Agonist of the σ-2A-adrenoreceptor
Agonist of the σ-2B-adrenoreceptor
Agonist of the σ-2C-adrenoreceptor
In addition, clonidine is an imidazoline receptor agonist.
If the dosage is too high too quickly (injected), clonidine may also act as a σ-1-adrenoreceptor agonist.
Clonidine attenuates the effect of epinephrine.
Alpha-2 adrenoreceptors are activated by the neurotransmitters adrenaline and noradrenaline. They are thus responsible for the effects mediated by adrenaline and noradrenaline.
Alpha 2-A receptor agonists such as clonidine and guanfacine are thought to enhance phasic norepinephrine release in the nucleus coeruleus, which improves attention as well as working memory and visuomotor-associated learning (in contrast to long-term tonic NE release, which worsens performance).
Clonidine thus has a noradrenergic effect.
As an alpha-2 adrenoceptor agonist, clonidine (like guanfacine) significantly reduces dopamine release in the nucleus accumbens in the laboratory.
Clonidine and guanfacine are reported to be helpful in Rejection Sensitivity in ADHD according to the field report of an American ADHD specialist.
A 2019 study from India reported that clonidine was the most commonly used medication for ADHD there in a group of children 3 to 6 years old with ADHD:
- Clonidine: 44, 6 %
- Risperidone: 28.7
- Methylphenidate: 10.7 %
- Atomoxetine: 10.7
2. Side effects
Side effects of clonidine have not yet been incorporated.
Clonidine has higher side effects than methylphenidate and atomoxetine.
In older individuals, endothelial damage (damage to the inner layer of blood vessels) may be more common. In these, clonidine could increase the risk of vascular damage and thrombosis.