This drug, Lodosyn, is manufactured by Merck, Sharp and Dohme (MSD). It is not sold in any store because it is free. All your doctor has to do is ask the MSD representative to ship a few boxes of the pills. Your doctor than can give these out to the patients free. They come in bottles of 100 pills of 25 mg of carbidopa per pill. It is generally thought that someone taking Carbidopa / Levodopa (sinemet) should take at least 75 mg of carbidopa and not more than 200 mg of carbidopa per day. It is thought that large amounts of caribidopa may inhibit the production of serotonin outside of the blood brain barrier. Regards, Alan Bonander ([log in to unmask])