The 2018 European Union (EU) approved weekly and monthly subcutaneous buprenorphine depot injection (BUP-XR), for opioid substitution medication proved to offer some specific treatment benefits. The present study examines the process of switching from buprenorphine sublingual tablets (BUP-SL) to BUP-XR from a patient's point of view. In total, nine patients were surveyed by means of an openanswer questionnaire regarding course and side effects of the medication switch. Six of these patients were surveyed in more detail under BUP-SL, as well as 4 and 16 weeks after the switch to BUP-XR by means of a test battery of questions on socio-demography, withdrawal symptoms, craving, physical well-being, treatment satisfaction and concomitant use of illegal substances. Patients reported significant worse physical well-being and lower treatment satisfaction in 4 weeks compared with 16 weeks after the medication switch to the BUP-XR. Furthermore, they reported significant more frequent co-use of illicit drugs, worse physical well-being, lower treatment satisfaction and more craving experience 4 weeks after the switch compared with the treatment under BUP-SL. Patients 16 weeks under BUP-XR reported significant more illicit co-use and lower treatment satisfaction compared with patients under BUP-SL. Connections between therapy dissatisfaction, physical discomfort, experienced craving and drug co-consumption were discovered. In the first weeks after the medication switch, patients experience potentially distressing symptoms, which, however, seem to diminish over time. Close supervision and comprehensive patient education on possible burdens of the medication switch to the BUP-XR might prevent unfavourable treatment courses and premature therapy dropouts.