• Abdurrahman Ahmed National Postgrduate Medical College of Nigeria (NPMCN)


Background: The pain of labour is normal, but it affects maternal psychology, labour
progress and foetal well-being. Consequently, one of the basic principles of modern
obstetrics is to provide adequate labour analgesia. Ideal labour analgesic should be
efficacious with minimal side effects to both the mother and foetus among other properties.
Parenteral opioids are common analgesic options worldwide, and have been the subject of
research for many years. Epidural analgesia still remains the gold standard, but for reasons
of cost and personnel it is not routinely available. This study was therefore, designed to
compare the effectiveness of tramadol and pentazocine for labour pain relief using Visual
Analogue Scale (VAS) scores.
Method: Following approval from the Ethical Committee of Aminu Kano Teaching Hospital,
Kano, 176 pregnant women at term and in spontaneous active phase of labour at term were
randomized into two groups that either received intramuscular (i.m) tramadol 100 mg or
i.m pentazocine 30 mg. Pain was assessed using VAS score before administration of the trial
drugs and at 30 minutes (min) interval until delivery and immediately after delivery and at
2 and 4 hours (h) after delivery. Presence of side effects were observed and recorded. The
parturients cardiorespiratory parameters; Pulse rate (PR), Systolic blood pressure (SBP),
Diastolic blood pressure (DBP), Mean arterial pressure (MAP), Respiratory rate (RR) and the
Foetal heart rate (FHR) were monitored and recorded at the said times above. Neonates’
APGAR (Appearance, Pulse, Grimace, Activity, and Respiration) scores and need for special
care baby unit (SCBU) admission were observed. Maternal satisfaction was also assessed
after delivery.

Results: A total of 165 parturients, 83 in the tramadol group and 82 in the pentazocine
group, completed the study. Eleven parturients were excluded, 6 of them delivered within
an hour of giving the trial drugs and the remaining 5 had caesarean section due to some
reasons. The mean VAS scores (±SD) of the parturient before administration of the trial drugs
were 6.932 (±0.866) and 6.912 (±0.774) in the tramadol and pentazocine groups
respectively. The VAS scores at 30 and 60 minutes after the trial drug administration were;
4.990 (±0.894) and 4.299(±0.748) in the pentazocine group, and 5.585 (±1.105) and 4.798
(±0.733) in the tramadol group respectively, with a p-value of <0.001 at both times. There
was no statistically significant difference in labour pain relief (mean VAS score) provided in
the two groups beyond 60 minutes (including after delivery) of administering the trial drug.
There were more side effects seen in the pentazocine group than in the tramadol group, 20
parturients (24.4%) compared to 11 parturients (13.3%) respectively (p=0.067). Both drugs
maintained stable cardiorespiratory parameters throughout the study period with no
significant difference between them. There were more neonates with APGAR scores <7 at 1
minute in the pentazocine group compared with the tramadol group, 5 neonates (6.1%)
compared with 3 neonates (3.6%) respectively (p=0.496). There was also no significant
difference between the groups APGAR scores at 5 min after birth, with only one neonate
(1.2%) in the pentazocine group and none (0%) in the tramadol group with APGAR score <7
(p=0.497). This same finding of APGAR scores at 5 min sustained at 10 min after birth. This
was the only newborn admitted to SCBU and none from the tramadol group (p=0.497). Forty
parturients (48.8%) and 19 (22.9%) in the pentazocine and tramadol groups respectively,
rated analgesia with the respective drugs as very good to excellent (p<0.001). Thirty seven

parturients (44.6%) in the tramadol group were not satisfied with the analgesia and rated it
poor to very poor compared to 10 parturients (12.2%) in the pentazocine group (P<0.001).
Conclusion: It was found from this study that i.m pentazocine 30 mg offered superior labour
pain relief than i.m tramadol 100 mg at 30 and 60 minutes after drug administration.
Similarly, maternal satisfaction was demonstrated more with i.m pentazocine 30 mg than
with i.m tramadol 100 mg for labour analgesia. Both drugs maintained stable maternal
cardiorespiratory parameters and FHR. However, higher incidence of maternal side effects
was observed in the pentazocine group than the tramadol group.