Glaucoma eyedrops

[Alice]

Hi!
I was diagnosed with glaucoma in October 2018 and have been using IOP lowering eyedrops ever since. My treatment plan includes betaxolol (drug name Betoptic S) in both eyes one drop twice a day and brinzolamide (drug name Azopt) in only one eye one drop twice a day. I also practice prolonged nasolacrimal duct occlusion (even up to ten minutes per drop, because as of shortly I've also been breast feeding).
I'm currently 45 years old and 16+ weeks pregnant. A few days ago I learned that my unborn baby has trisomy 13 (Patau syndrome). Naturally I'm now concerned that the medications may have played a role in that. The pregnancy wasn't planned and although both of the eyedrops I'm using are class C medications my opthalmologist deemed the risk to my vision greater if discontinuing the medications than any risk to the baby. And that is why I continued using these eye drops during my pregnancy including the first trimester.
I'm not on any other prescription medication.
I would be very grateful if you could help me understand this situation a little bit better.
Thank you for all the great work you're doing.
Alice

[kaytlin]

Hi Alice,

Thank you for your patience! Typically, the amount of drug absorbed into your body from eyedrops is low. Small amounts of brinzolamide and betaxolol are found in your blood after use, but not a clinically relevant amount (maybe 1/10 to 1/20th compared to an oral dose at most). Nasolacrimal duct occlusion will also limit absorption (good job!). This isn't enough to have clinical effects on you, and the amount to a baby through breastmilk would cut that amount down significantly again. It is highly doubtful this would cause issues in a breastfed baby. With the precautions to limit absorption, even in pregnancy, it is likely your benefit would outweigh the small risk to the baby. I'd just try and stay at the lowest effective dose.

It is entirely natural for you to worry that you might have done something to cause these issues in your baby, but I doubt that they are founded. I hope to give you some peace of mind that your medications were likely not the root of the genetic variations in your baby. I reviewed the toxicology data that we have for animals with these drugs. These studies use oral doses of ~100-600 times what you are using, hoping to encourage problems to become visible. The malformations that were observed were not the same as your child's.

Best,
Kaytlin Krutsch, PharmD