Pentazo IM/IV/SC Pentazocine Morphine Sulfate
MajorDo not give pentazocine to a patient who has already been treated with morphine, a pure opioid. Buprenorphine and nalbuphine come under the same warning.
These medicines can affect each other in a serious way. Do not start taking them together unless your doctor has said it is OK. If you already take both, do not stop either one on your own: speak to your doctor or pharmacist soon.