Timolol concentrations in breast milk of a woman treated for glaucoma: calculation of neonatal exposure

J Glaucoma. 2008 Jun-Jul;17(4):329-31. doi: 10.1097/IJG.0b013e31815c3a5b.


A 32-year-old lactating woman with open-angle glaucoma used timolol maleate 0.5% eye drops twice daily to her right eye for 6 months. Four milk samples were collected over a span of 6 days. Timolol maleate milk levels were examined by liquid chromatography tandem mass spectrometry and found to be at a mean of 0.12 ng/mL (range, 0 to 0.37 ng/mL). At this level, the theoretical maximum relative infant dose expressed as a percentage of the weight-adjusted maternal dose was 0.012%. As most glaucoma patients administer drops to both eyes, the dosage was duplicated to reflect the more pertinent calculated theoretical relative infant dose of 0.024%. This dose of timolol is unlikely to cause systemic side effects to the healthy breastfed infant.

MeSH terms

  • Adult
  • Antihypertensive Agents / administration & dosage
  • Antihypertensive Agents / pharmacokinetics*
  • Breast Feeding
  • Drug Therapy, Combination
  • Female
  • Glaucoma, Open-Angle / drug therapy*
  • Glaucoma, Open-Angle / metabolism*
  • Humans
  • Infant, Newborn
  • Maternal Exposure
  • Milk, Human / metabolism*
  • Pregnancy
  • Prenatal Exposure Delayed Effects*
  • Timolol / administration & dosage
  • Timolol / pharmacokinetics*


  • Antihypertensive Agents
  • Timolol