The respiratory effects of codeine and morphine in man.
D000704:Analysis of Variance; D003061:Codeine / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D012119:Respiration / Q000187:drug effects*
D009020:Morphine; D003061:Codeine