Selegiline: L-deprenyl; C13H17N
Brand names: Movergan, Antiparkin, Xilopar as well as generic
1. Mechanisms of action of selegiline
Selegiline is an MAO inhibitor used primarily in Parkinson’s disease. At low doses, it is a selective MAO-B inhibitor.
Selegiline irreversibly inhibits MAO-B, reducing dopamine degradation. In the process, selegiline itself is metabolized to amphetamines or methamphetamines.
In higher doses (above 20 mg/day), selegiline additionally inhibits MAO-A, which increases serotonin and norepinephrine levels in the brain.
Furthermore, selegiline acts as a dopamine reuptake inhibitor.
2. Selegiline for ADHD
One study comparing 20 mg and 60 mg selegiline versus placebo found no improvement in self-report ADHD symptomatology in the subjects. Another study of 24 children with ADHD and comorbid Tourette’s found only modest improvements in ADHD symptomatology while maintaining a high dropout rate among participants
An older study found good improvement in ADHD symptoms with selegiline in children with ADHD and comorbid tic disorder over a test period of more than 6 months. Only 2 of the 29 subjects reported worsening of tics. Side effects were mild.
Three smaller studies found no difference in effect between selegiline and methylphenidate in parent report in 15 families, in parent and teacher report in 28 children, and in parent and teacher report in 40 children.
In another small placebo-controlled study, selegiline improved only inattention but not hyperactivity/impulsivity. In animal studies, a significant reduction in impulsivity was found in SHR (animal model of ADHD-C) at as little as 0.25 mg/kg
Selegiline appears to be used at times off-label for ADHD.
3. Selegiline side effects
- Dry mouth
- Movement disorders
- Blood pressure drop
- moderate elevation of liver enzymes
The side effects of
- Loss of appetite
- Sleep problems
were slightly less frequent with selegiline than with methylphenidate, with otherwise comparable amounts of side effects.
4. Contraindications of selegiline
- Extrapyramidal syndromes not due to dopamine deficiency
- Impaired kidney or liver function
- Stomach or intestinal ulcers
- Pregnancy and lactation
Selegiline must not be combined with:
- tricyclic antidepressants
- Serotonin agonists
A study of comedication of stimulants and MAO inhibitors in depression found no problems arising. Another study reported successful comedication of selegiline and lisdexamfetamine (Vyvanse) in ADHD and comorbid depression
Thus, combination medication of selegiline with stimulants may also be considered for ADHD.