Lurbinectedin is a medication used for the treatment of metastatic small cell lung cancer in patients who have previously received chemotherapy [2]. However, there is limited information on the use of lurbinectedin by breastfeeding mothers. The drug is not recommended for use during breastfeeding as it is unknown whether it is excreted in human milk [2]. Therefore, breastfeeding mothers should consult with their healthcare provider before using lurbinectedin.

According to the drug label, women of reproductive potential should use effective contraception during treatment with lurbinectedin and for at least six months after the last dose of the drug [2]. This is because lurbinectedin can cause fetal harm when administered to a pregnant woman [2].

The Mayo Clinic lists some common side effects of lurbinectedin, including nausea, vomiting, fatigue, decreased appetite, constipation, and diarrhea [3]. However, it is unclear if these side effects can affect breastfeeding mothers or their infants.

In conclusion, breastfeeding mothers should avoid using lurbinectedin unless it is deemed necessary by their healthcare provider. Women of reproductive potential should use effective contraception during treatment with lurbinectedin and for at least six months after the last dose of the drug. Common side effects of lurbinectedin include nausea, vomiting, fatigue, decreased appetite, constipation, and diarrhea [2][3].

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LURBINECTEDIN
[2] https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/213702s000lbl.pdf
[3] https://www.mayoclinic.org/drugs-supplements/lurbinectedin-intravenous-route/side-effects/drg-20490804?p=1