by Jack Newman, MD, FRCPC
When domperidone was being used for babies (and now that cisapride is off the market, it is being used again), it was common for the babies to be on the medication for several months, even longer. Since the amount of domperidone that gets into the milk is very small indeed, from the baby's point of view, there should be no issue in the mother taking it to increase milk supply for several months.
Our experience with this drug is that short-term side effects are very few and almost always very mild. Worldwide experience with domperidone over at least two decades suggests that long-term side effects also are rare. Some of the mothers in our clinic, breastfeeding adopted babies, have been on the medication for 18 months without any apparent side effects. As mentioned in the information sheet Domperidone, Getting Started, patients using domperidone for stomach disorders may be on it for many years. We hope you won't need domperidone for very long, but if it's necessary and helpful, stay on it.
It depends on the situation. In a situation where the mother had had a good milk supply, but it decreased for some reason (e.g. going on the birth control pill, see the information sheet Slow Weight Gain Following Early Good Weight Gain), domperidone often works very rapidly to increase the milk supply. Often, within a day or two the mother is seeing a difference (and so does her baby).
But this is not always so, and in many situations, it may take a week or more for the mother to start getting an effect. On occasion, we have had mothers only starting to get an increase in their milk supplies a month or more after starting to take it. Therefore, we generally recommended that the mother take the domperidone for at least six weeks in order to be sure whether it has worked or not.
It is our impression that domperidone works best after the first few weeks after the mother has given birth (usually after about four weeks). This has not been proved, but there are theoretical reasons why it may be so. For this reason, we have often waited to prescribe it until the baby is at least three weeks, mainly because we did not want the mother to become discouraged if she did not see any rapid increase in her milk supply. If you keep this in mind, taking domperidone before three or four weeks after the birth of the baby is worth a try because sometimes it does work very well early on.
Usually, we ask the mother take it for at least two weeks at a minimum and then re-evaluate the situation. There are several possibilities.