Safety in Lactation: Neuromuscular blocking drugs

Sarah Fenner, Acting Co-Director, Midlands and East Medicines Advice Service (Midlands site) & UK Drugs in Lactation Advisory ServicePublished

Neuromuscular blocking drugs are used to induce muscle relaxation prior to surgery. With the exception of suxamethonium, they are all nearly completely ionised at physiological pH which inhibits the transfer of the drug into breast milk. Only the proportion of unionised drug remaining can pass into breast milk and this is too small to pose a risk to the infant.
Suxamethonium is rapidly inactivated in maternal plasma and therefore poses no risk to the breastfed infant.
It is therefore considered that breastfeeding can be resumed as soon as the mother has recovered sufficiently from the effects of general anaesthesia.