Washington: Researchers have found that a few drugs used for treating retinal diseases may mix with breast milk, further causing a safety issue for the growing infants.
Ranibizumab and aflibercept are medications used to treat several retinal diseases. They contain an agent called anti-vascular endothelial growth factor (anti-VEGF), which blocks the eye's production of vascular endothelial growth factor (VEGF).
VEGF is a protein that stimulates the development of blood vessels but is associated with retinal diseases in high quantities.
VEGF is present in breast milk and plays an important role in the development of an infant's digestive system. As a result, anti-VEGF drugs in a nursing mother raise concerns about possible adverse events in a developing infant if the drugs were to pass into breast milk and suppress VEGF.
The study published in the journal, 'Ophthalmology' is a first-of-its-kind study led by St. Michael's Hospital in Toronto.
"As retina specialists, we often tell our pregnant or nursing patients that there's a risk of a small amount of these drugs making its way into the breast milk, but we can't be sure," said Dr Rajeev Muni, co-lead author, a vitreoretinal surgeon at St. Michael's and a project investigator at the hospital's Li Ka Shing Knowledge Institute.
"We don't want these patients to lose their vision so we make a decision, despite limited information," added Dr Muni.
Hoping to change this, Dr Muni and Dr Verena Juncal, co-lead author and a retinal fellow at St. Michael's, measured the concentrations of retinal medications in the breast milk of three lactating patients following injection of anti-VEGF therapy.
The team found that the drugs were excreted into the breast milk within the first couple days following injection, with a corresponding reduction in VEGF levels.
They also found that the amount of medication detected in the patient who continued to breastfeed was significantly lower than the other two patients, suggesting that the medication was constantly excreted and ingested by the infant.
"These results definitively show us that the drug reaches the breast milk," said Dr Juncal. "We realise that some readers may question the small sample size, but if the drug reaches the breast milk in three patients, it'll reach in 30 patients because it's the same biological process."
As the first study to evaluate the presence of Health Canada approved anti-VEGF therapy in human breast milk, these results provide a resource for ophthalmologists and retina specialists counselling pregnant and nursing patients.
"I'm comforted knowing that other pregnant or nursing mothers with retinal diseases will have the information needed to make an educated decision about whether to consider nursing while receiving these medications," said Lisa, one of the three study participants, who didn't want to reveal her surname.