Complex sentence: Risk of overdose is less with buprenorphine/naloxone than with methadone, however, people are more likely to stop treatment on buprenorphine/naloxone than methadone.
Split into simpler sentences: Risk of overdose is less with buprenorphine/naloxone than with methadone. However, people are more likely to stop treatment on buprenorphine/naloxone than methadone.