Immediate release Ritalin reaches peak levels in the blood in
about 2 hours and the half-life of this form of Ritalin is between
1-3 hours. The extended release version of Ritalin (Ritalin SR) is meant to work throughout the day, but lasts for
about 8 hours. The half-life of Ritalin SR is an average of 3.5 hours.May 31, 2012
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