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The effect of morphine and naloxone administration on plasma oxytocin concentrations in the first stage of labour
Author(s) -
Lindow Stephen W.,
Spuy Zephne M.,
Hendricks M. Salle,
Rosselli Andrew P.,
Lombard Carl,
Leng Gareth
Publication year - 1992
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1992.tb02337.x
Subject(s) - oxytocin , (+) naloxone , opiate , morphine , medicine , endocrinology , antagonist , receptor
OBJECTIVE We Investigated the effect of an oplate (morphine) and an opiate antagonist (naloxone) on the maternal secretion of oxytocin in the first stage of labour. DESIGN Patients were randomized to receive either morphine 5 mg ( n = 9), naloxone 1.2 mg ( n = 10) or sterile water ( n = 9) which was injected intravenously. PATIENTS Healthy women in the first stage of labour between 3 and 6 cm dilated with no prior analgesia or oxytocin administration were recruited for the study. MEASUREMENTS Peripheral maternal oxytocin levels were measured by radloimmunoassay for 15 minutes before and 15 minutes after administration of the assigned substance. Sampling was at 2.5 minute intervals. RESULTS Significant reduction in the mean oxytocin concentration was found in the patients who received morphine (— 2.62 pmol/l/sample) but no change was found in the naloxone group (+ 0.57 pmol/l/sample) when compared with controls (+ 0.64 pmol/l/sample). CONCLUSION Maternal oxytocin secretion is inhibited by exogenous opiates in the first stage of labour while an effect of opiate antagonism was not demonstrated.