I have arrhythmia, would ritalin (methylphenidate) or dexedrine be dangerous for me to use? which is safer and in what dosage?

Possibly: Ritalin (methylphenidate) and Dexedrine are stimulants which can aggravate pre-existing arrhythmias. The severity of the adverse effect depends upon the underlying rhythm disorder, and to some extent, the dose of these medications. For some conditions, i recommend avoidance of stimulants in any dose whereas for others I am less strict. You shoul discuss with your doctor.

Possibly: If you have an existing arrhythmia, it is possible that Ritalin (methylphenidate) or Dexedrine will exacerbate the arrhythmia; it really depends on the particular type of arrhythmia. You should consult with your physician before you start either Ritalin (methylphenidate) or Dexedrine so that the appropriate recommendation can be made and your condition monitored.