• A 34-year-old nursing woman with elevated intraocular pressure voluntarily and without our knowledge applied 0.5% timolol maleate twice daily to her right eye. A milk sample 1.5 hours after administration of drug showed a much higher level of timolol (5.6 ng/mL) than a plasma sample drawn at the same time (0.93 ng/mL). Three control milk specimens showed no measurable levels of timolol. The patient's milk sample 12 hours after her last timolol dose contained 0.5 ng/mL of timolol. On the basis of our calculations, timolol should be used with caution by nursing mothers.
Lustgarten JS, Podos SM. Topical Timolol and the Nursing Mother. Arch Ophthalmol. 1983;101(9):1381-1382. doi:10.1001/archopht.1983.01040020383008