Methylphenidate (Brand name: Ritalin)

- Feburary 1999 Molecule of the Month

Methylphenidate is a mild Central Neverous System stimulant.

The mode of action in man is not completely understood, but methylphenidate presumably activates the brain stem arousal system and cortex to produce its stimulant effect. There is neither specific evidence which clearly establishes the mechanism where by methylphenidate produces its mental and behavioral effects in children, nor conclusive evidence regarding how these effects relate to the condition of the Central Neverous System.

Methylphenidate is used for Attention-Deficit Hyperactivity Disorder (ADHD) as an integral part of a total treatment program. This typically includes other remedial measures (psychological, educational, social) for a stabilizing effect in children with a behavioral syndrome characterized by the following group of developmentally inappropriate symptoms: moderate-to-severe distractibility, short attention span, hyperactivity, emotional lability, and impulsivity.

Figure. 3D Structure of Ritalin (click on this image to view it's interactive 3D sturucture)

Methylphenidate should not be used in children under 6 years of age, since safety and efficacy in this age group have not been established.

Drug treatment is not used for all children with this syndrome. Stimulants are not intended for use in the child who exhibits symptoms secondary to environmental factors and/or primary psychiatric disorders, including psychosis. Appropriate educational placement is essential and psychosocial intervention is generally necessary. When remedial measures alone are insufficient, the decision to prescribe stimulant medication will depend upon the physician's assessment of the chronicity and severity of the child's symptoms.

Although a causal relationship has not been established, suppression of growth (i.e. weight gain and/or height) has been reported with the long-term use of stimulants in children. Therefore, patients requiring long-term therapy should be carefully monitored. In addition, the use of "Drug Holidays" is recommended, that is, withholding the drug on weekends and during school holidays in as much as the clinical situation permits.

Nervousness and insomnia are the most common adverse reactions reported with methylphenidate but are usually controlled by reducing dosage and omitting the drug in the afternoon or evening. Decreased appetite is also common but usually transient.

Dizziness, drowsiness, headache, and dyskinesia may occur. Isolated cases of the following have been reported: hyperactivity, convulsions, muscle cramps, choreo-athetoid movements, tics, or exacerbation of pre-existing tics, Tourette's syndrome, and psychotic episodes including hallucinations which subsided when methylphenidate was discontinued. Psychic dependence in emotionally unstable persons has occurred rarely with chronic treatment. Although a definite causal relationship has not been established, isolated cases of transient depressed mood have been reported.

Ritalin should be periodically discontinued to assess the child's condition. Improvement may be sustained when the drug is either temporarily or permanently discontinued. Drug treatment should not and need not be indefinite and usually may be discontinued after puberty.