My 5 year old son just started taking a medication for adhd called methylphenid. he is blinking a million times. is this normal?

No: If new, this is probably a reaction to the medicine.Call the prescribing physiscian.

Tic: This is a "tic" and can be a side effect of stimulant medications used for adhd. You need to promptly notify his prescribing doctor. There are alternative medications.

Options: Usually any side effect of stimulants is gone within 24-48, but stimulant-induced tics may take a little longer. When back to baseline, your child may be put on a trial of the other stimulant medication, which won't necessarily cause the same side effect. If it does, the next step would be a non-stimulant medication. Tics will not hurt your child neurologically, only socially.