Medical Health Encyclopedia

Alpha-2 Agonists (Clonidine)

Alpha-2 agonists stimulate the neurotransmitter norepinephrine, which appears to be important for concentration. They include clonidine (Catapres) and guanfacine (Tenex). They are used for Tourette's syndrome and may be beneficial when other drugs have failed for ADHD children with tics or those whose primary symptoms are severe impulsivity and aggression.

These drugs have a number of side effects. (Guanfacine may have fewer than clonidine.) Sedation is the most common. A clonidine skin patch, which gradually releases the medication, helps reduce the sedative effect. Because clonidine slows the heart down, it can have adverse effects in some children. Going off too quickly or missing doses can cause rapid heartbeats and other symptoms that may lead to severe problems.

Studies in general report that the drug is safe, including in combination with stimulants. Of concern, however, were reports of five deaths in children taking clonidine with other medications. Experts strongly recommend that no child be given this medication without a preliminary examination for heart problems, and no child with existing heart, kidney, or circulatory problems should take it.

Other Medications Investigated for ADHD

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Selegiline. Selegiline (Eldepryl, Movergan, Zelepar), also known as deprenyl, metabolizes into compounds found in methamphetamine and blocks monoamine oxidase B (MAO-B), an enzyme that degrades dopamine. A well-conducted study in 2003 suggested that it may be as effective as Ritalin with fewer size effects. Selegiline can cause hypertension if combined with drugs that increase serotonin levels--such drugs include nearly every major antidepressant.

Modafinil. Modafinil (Provigil) promotes wakefulness and is used to treat patients with narcolepsy. It is being investigated for adults and children with ADHD, but studies have been mixed on its benefits.