Abstract
Objective: To investigate the compatibility of oxytocin and
tranexamic acid injection products when mixed for the purpose of
co-administration by intravenous infusion.
Population or Sample: Oxytocin and tranexamic acid were collected
from hospitals taking part in a multicentre postpartum haemorrhage
treatment (E-MOTIVE) trial in Kenya, Nigeria, Tanzania, and South
Africa.
Methods: The compatibility of two sentinel products of oxytocin
injection and tranexamic acid injection in 200mL infusion bags of both
0.9%w/v saline and Ringer’s Lactate was assessed. We analysed all
tranexamic acid -oxytocin combinations, and each evaluation was
conducted for up to 6hrs. Subsequently, the compatibility of multiple
tranexamic acid products with reference oxytocins products when mixed in
0.9%w/v saline over a period of 1 hour was investigated.
Results: We found a significant interaction between certain
oxytocin and tranexamic acid products after mixing them in vitro and
observing for 1 hour. The interaction substantially impacted oxytocin
content leading to reduction in concentration (14.8% - 29.0%)
immediately on mixing (t=0 minutes). In some combinations, the
concentration continued to decline throughout the stability assessment
period. Oxytocin loss was observed in 7 out of 22 (32%) combinations
tested.
Conclusions: In a clinical setting, mixing oxytocin and
tranexamic acid may result in an underdosing of oxytocin, compromising
care in an emergency life-threatening situation. The mixing of oxytocin
and tranexamic acid injection products for co-administration with IV
infusion fluids should be avoided until the exact nature of the
interaction and its implications are understood.