Hogerzeil H V, Walker G J
World Health Organization, Action Programme on Essential Drugs, Geneva, Switzerland.
Eur J Obstet Gynecol Reprod Biol. 1996 Oct;69(1):25-9. doi: 10.1016/0301-2115(95)02530-8.
Parenteral ergometrine is widely used for the prevention and treatment of excessive uterine bleeding following birth. Unfortunately, in tropical climates it is often found to contain very little active ingredient: only 32 of 100 field samples from Bangladesh, Gambia, Malawi, Yemen and Zimbabwe contained 90-110% of the amount of active ingredient stated on the label, and 34 contained less than 60%. In this paper the results of nine studies, of which eight were initiated and coordinated by WHO, are reviewed to formulate answers to the following questions: (1) what is the extent of the problem of low potency of ergometrine in tropical climates; (2) is the problem due to instability or low initial quality, or both; (3) which practical measures can assure the quality of injectable ergometrine; and (4) are there any alternative drugs which are more stable? Injectable ergometrine is very unstable under tropical conditions and particularly if stored unrefrigerated and exposed to light, when it may loose up to 20% of its potency per month. However, there are differences between brands. Practical measures to assure the quality of injectable ergometrine therefore include a careful supplier selection and refrigerated storage. Ergometrine injection should always be protected from light until given to the patient. Loss of active ingredient can easily be detected by regular visual checks of the colour of the solution. Any discoloration implies that the solution contains less than 90% of the stated amount of active ingredient, and should not be used. Methylergometrine is no more stable than ergometrine. Parenteral oxytocin is more stable than both ergometrine and methylergometrine injection. Oral and buccal dosage forms are less stable than injections. In view of the better stability in tropical climates, similar cost, fewer side effects and comparative efficacy, parenteral oxytocin, rather than parenteral ergometrine, is the drug of choice in the prevention and treatment of postpartum haemorrhage.
注射用麦角新碱被广泛用于预防和治疗产后子宫出血过多。遗憾的是，在热带气候条件下，人们常常发现其活性成分含量极低：来自孟加拉国、冈比亚、马拉维、也门和津巴布韦的100份现场样本中，只有32份所含活性成分量为标签标注量的90 - 110%，34份所含活性成分量低于60%。本文回顾了9项研究的结果，其中8项由世界卫生组织发起和协调，以回答以下问题：（1）热带气候条件下麦角新碱效力低的问题有多严重；（2）该问题是由于稳定性差还是初始质量低，抑或是两者皆有；（3）哪些实际措施可以确保注射用麦角新碱的质量；（4）是否有更稳定的替代药物？注射用麦角新碱在热带条件下非常不稳定，尤其是在未冷藏且暴露于光线下时，每月其效力可能会损失高达20%。然而，不同品牌之间存在差异。因此，确保注射用麦角新碱质量的实际措施包括谨慎选择供应商和冷藏储存。麦角新碱注射液在给患者使用前应始终避光保存。通过定期目视检查溶液颜色可以很容易地检测到活性成分的损失。溶液变色意味着其所含活性成分量低于标注量的90%，不应使用。甲基麦角新碱的稳定性并不比麦角新碱好。注射用缩宫素比麦角新碱和甲基麦角新碱注射液都更稳定。口服和颊用剂型比注射剂稳定性差。鉴于在热带气候下稳定性更好、成本相似、副作用更少且疗效相当，预防和治疗产后出血的首选药物是注射用缩宫素，而非注射用麦角新碱。
