Ritalin should not be used in children under six years, since safety and efficacy in
this age group have not been established.
Sufficient data on safety and efficacy of long-term use of Ritalin in children are
not yet available. 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
Ritalin should not be used for severe depression of either exogenous or endogenous origin.
Clinical experience suggests that in psychotic children, administration of Ritalin may
exacerbate symptoms of behavior disturbance and thought disorder.
Ritalin should not be used for the prevention or treatment of normal fatigue states.
There is some clinical evidence that Ritalin may lower the convulsive threshold in patients
with prior history of seizures, with prior EEG abnormalities in absence of seizures, and,
very rarely, in absence of history of seizures and no prior EEG evidence of seizures. Safe
concomitant use of anticonvulsants and Ritalin has not been established. In the presence of
seizures, the drug should be discontinued.
Use cautiously in patients with hypertension. Blood pressure should be monitored at appropriate
intervals in all patients taking Ritalin, especially those with hypertension.
Symptoms of visual disturbances have been encountered in rare cases. Difficulties with accommodation
and blurring of vision have been reported.
Usage in Pregnancy
Adequate animal reproduction studies to establish safe use of Ritalin during pregnancy have not been
conducted. However, in a recently conducted study, methylphenidate has been shown to have teratogenic
effects in rabbits when given in doses of 200 mg/kg/day, which is approximately 167 times and 78 times
the maximum recommended human dose on a mg/kg and a mg/m basis, respectively. In rats, teratogenic
effects were not seen when the drug was given in doses of 75 mg/kg/day, which is approximately 62.5
and 13.5 times the maximum recommended human dose on a mg/kg and a mg/m basis, respectively. Therefore,
until more information is available, Ritalin should not be prescribed for women of childbearing age
unless, in the opinion of the physician, the potential benefits outweigh the possible risks.
Ritalin may decrease the hypotensive effect of guanethidine. Use cautiously with pressor agents.
Human pharmacologic studies have shown that Ritalin may inhibit the metabolism of coumarin anticoagulants, anticonvulsants (phenobarbital, diphenylhydantoin, primidone), phenylbutazone, and tricyclic drugs (imipramine, clomipramine, desipramine). Downward dosage adjustments of these drugs may be required when given concomitantly with Ritalin.
Serious adverse events have been reported in concomitant use with clonidine, although no causality for the combination has been established. The safety of using methylphenidate in combination with clonidine or other centrally acting alpha-2 agonists has not been systemically evaluated.
Marked anxiety, tension, and agitation are contraindications to Ritalin, since the drug may aggravate these symptoms. Ritalin is contraindicated also in patients known to be hypersensitive to the drug, in patients with glaucoma, and in patients with motor tics or with a family history or diagnosis of Touretteís syndrome.
Ritalin is contraindicated during treatment with monoamine oxidase inhibitors, and also within a minimum of 14 days following discontinuation of a monoamine oxidase inhibitor (hypertensive crises may result).