I have restless legs why do I need to take amatriptlene?

As far as I know Amitriptyline isn't usually prescribed to treat Restless Leg Syndrome. Your doctor may have thought the sedative like effect the drug has would calm you down and make you less likely to more or jerk your legs. The main purpose of the drug is to treat depression but that is at higher doses. It can also be prescribed to treat pain over long periods of time. If you feel it isn't working for you then you also always go back to your doctor and request a different type of medication. Depending on the cause of your Restless Leg Syndrome would make a difference to which type of medication is used. If it's pain related then muscle relaxant or opiate based medications may be the better option as they would have a stronger effect than Amitriptyline. The risk is that both types of the medications I mentioned can be addictive and some aren't suitable for long term use. It is important that you emphasize to your doctor that you want to find and treat the underlying cause of your Restless Leg Syndrome rather than solely treating the RLS alone. I hope I've been of some help and good luck with your condition.