Safety in Lactation: Protein kinase inhibitors

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

Protein kinase inhibitors, whether used as monotherapy or in combination with other antineoplastics, are contra-indicated in breastfeeding because of their effects on dividing cells and their varied and high toxicity in normal therapeutic use.
The risks associated with their use will be additive with other antineoplastic agents when used in combination.
In most cases it will not be possible to suggest an alternative. Choice of drug will depend on a number of disease and treatment protocol parameters.
There is no evidence-based, definitive time period after treatment when breastfeeding can be safely resumed, especially when drugs are used in combination. Therefore, if use of a protein kinase inhibitor is deemed clinically necessary, breastfeeding should be discontinued.