What are the possible side effects of Ritalin (methylphenidate)?

If you experience any of the following serious side effects, stop taking Ritalin (methylphenidate) and seek emergency medical attention or contact your doctor immediately:

• an allergic reaction (difficulty breathing; closing of the throat; swelling of the lips, tongue, or face; or hives).
• an irregular or fast heartbeat.
• chest pains or very high blood pressure (blurred vision, severe headache, flushing);
  unusual behavior or confusion.
• or liver damage (yellowing of the skin or eyes, nausea, abdominal pain or discomfort, unusual bleeding or bruising, severe fatigue).

Other, less serious side effects may be more likely to occur. Continue to take Ritalin (methylphenidate) and talk to your doctor if you experience.

• insomnia (difficulty sleeping).
• nervousness.
• drowsiness.
• dizziness.
• headache.
• blurred vision.
• tics (repetitive movements).
• abdominal pain, nausea, or vomiting.
• decreased appetite or weight loss.
• slower weight gain and/or growth.

Ritalin (Methylphenidate) may cause drug dependence.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.