Hello, For knee pain, there are medicines which a physician can prescribe based in the clinical examination. Taking alternatives may not be advised as due to medical reasons. If your parents have knee pain than I suspect they in ageing, and taking medicine without physician advice may not sound good. Because later on the mistake can be put on others head easily. Since the medicine is over, why not trying doing hot water fermentation, using knee brace and exercises. Physical therapy has been effective in knee pains in ageing patients. Sorry to not guide for medicines but I will only be able to mention about exercises here. Hope I have answered your query. Let me know if I can assist you further. Regards, Jay Indravadan Patel, Physical Therapist or Physiotherapist