Naltrexone is a very safe medication that has been used for many years. The implants are generally very well tolerated. Beside the side-effects mentioned above, program participants can report itching, tenderness, swelling, pain, irritation, inflammation, or infection around the surgical site. The majority of cases of irritation or inflammation resolve with time. Often, antihistamines and topical and/or oral steroids are used to help treat the local inflammation. In cases of infection, antibiotics may be needed. In the very unlikely case of severe infection or inflammation, a doctor may recommend removal of the implant. The implant is contraindicated in individuals with acute hepatitis, advanced liver disease, or kidney failure. Pregnant or breastfeeding women should consult with their physician before beginning Naltrexone treatment. The implant is surgically placed, and there will be a small linear surgical scar. Each individual scars differently. In some cases, a small nodule of fibrous tissue may remain palpable under the skin. Although very unlikely, as with any foreign body there is a risk of rejection, tissue breakdown, and necrosis.