This pilot study will last a total of 8 weeks. Recently detoxified opiate dependent participants who are eligible for naltrexone treatment will enter a 4-week single-blind dose tolerability phase, during which participants will receive naltrexone and 1 of 3 twice-daily lofexidine induction schedules. All participants will be required to remain in the clinic for 2 hours immediately following dosing in order to monitor vital signs and side effects. Study visits will occur three times each week, at which time naltrexone medication for self-administration will be handed out and participants will be evaluated in terms of tolerability to treatment. After the 4 weeks of treatment, a double-blind lofexidine detoxification phase using a 5-day taper will occur. Participants will be randomly assigned to one of two maintenance-taper schedules. The first group will undergo a 5-day tapering, followed by a placebo for three weeks, followed by a 5-day tapering during Week 4. Withdrawal symptoms and side effects will be evaluated.