Extradural morphine for the relief of pain following caesarean section. 
Thirty patients took part in a double-blind trial to compare morphine 10 mg i.m.  with morphine 5 mg into the extradural space for pain relief following Caesarean section.  With the extradural route the mean time to first analgesia was 7.95 h compared with 4.75 h for the i.m.  route.  The mean number of further doses of diamorphine 7.5 mg required for pain relief in the first 24 h was 1.93 (+/- 0.30) in the i.m.  group and 1.46 (+/- 0.31) in the extradural group.  There was a small but definite advantage in the use of the extradural route for the initial dose of morphine.  No serious side-effects were noted in either group.