<unk> (rectal) is an analgesic that is FDA approved for the treatment of pain.   Common adverse reactions include anxiety, fear, dysphoria, dizziness, Orthostatic hypotension,urinary retention, nausea, vomiting and pruritus.
Hydromorphone 
Oxymorphone 
Morphine 
Nalorphine
Normorphine
Ropivacaine
Butorphanol 
Meperidine 