Hi,
Concreta contains 
methylphenidate which is 
central nervous system stimulant that controls impulses and hyperactivities in the brain and nerve is used to treat attention deficit 
hyperactivity disorder in children 6 years of age or older and adults. Long term side effects of concreta are  high potential for abuse, dependency, depression, depression, irregular heartbeat, rash, headache, diarrhea, dizziness, drowsiness, double vision, difficulty in swelling, difficulty in swallowing, blood in urine or stool, chest pain, cough, chills, confusion, inability to speak, inability to move arms, legs or 
facial muscles, loss of interest, loss of concentration, runny nose, irritability, tremors, respiratory difficulties, dryness of mouth, oral ulcer, difficulty in micturition, nausea, vomiting, sweating,  
hallucinations, restlessness, nervousness, anxiety, weight loss etc.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Zubayer Alam, General And Family Physician,