The Basics
What is Timolol?
Used to treat glaucoma by decreasing the pressure in the eye.
Brand names for Timolol
Blocadren
How Timolol is classified
Antihypertensive Agents, Adrenergic Beta-Antagonists, Antiarrhythmics, Antiglaucoma Agents
Timolol During Pregnancy
Timolol pregnancy category
Category CNote that the FDA has deprecated the use of pregnancy categories, so for some medications, this information isn’t available. We still think it’s useful to list historical info, however, given what a common proxy this has been in the past.
What we know about taking Timolol while pregnant
Teratogenicity studies with timolol in mice, rats and rabbits at doses up to 50 mg/kg/day (approximately 40 times** the maximum recommended daily human dose) showed no evidence of fetal malformations. Although delayed fetal ossification was observed at this dose in rats, there were no adverse effects on postnatal development of offspring. Doses of 1000 mg/kg/day (approximately 830 times** the maximum recommended daily human dose) were maternotoxic in mice and resulted in an increased number of fetal resorptions. Increased fetal resorptions were also seen in rabbits at doses of approximately 40 times** the maximum recommended daily human dose, in this case without apparent maternotoxicity. There are no adequate and well-controlled studies in pregnant women. BLOCADREN (timolol) should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Taking Timolol While Breastfeeding
What are recommendations for lactation if you're taking Timolol?
Because of the variability in excretion of timolol into breastmilk and minimal reported experience during breastfeeding, other agents may be preferred, especially while nursing a newborn or preterm infant. Ophthalmic use of timolol by the mother should pose little risk to the breastfed infant. To substantially diminish the amount of drug that reaches the breastmilk after using eye drops, place pressure over the tear duct by the corner of the eye for 1 minute or more, then remove the excess solution with an absorbent tissue.
Maternal / infant drug levels
Because of the variability in excretion of timolol into breastmilk and minimal reported experience during breastfeeding, other agents may be preferred, especially while nursing a newborn or preterm infant. Ophthalmic use of timolol by the mother should pose little risk to the breastfed infant. To substantially diminish the amount of drug that reaches the breastmilk after using eye drops, place pressure over the tear duct by the corner of the eye for 1 minute or more, then remove the excess solution with an absorbent tissue.
Possible effects of Timolol on milk supply
Relevant published information on the effects of beta-blockade or timolol during normal lactation was not found as of the revision date. A study in 6 patients with hyperprolactinemia and galactorrhea found no changes in serum prolactin levels following beta-adrenergic blockade with propranolol.[8]
Possible alternatives to Timolol
(Systemic) Propranolol, Labetalol, Metoprolol; (Ophthalmic) Levobunolol, Metipranolol.
List of References
Lactation sources: Drugs and Lactation Database (LactMed) [Internet]. Bethesda (MD): National Library of Medicine (US); 2006-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK501922/1. Riant P, Urien S, Albengres E et al. High plasma protein binding as a parameter in the selection of betablockers for lactating women. Biochem Pharmacol. 1986;35:4579-81. PMID: 2878668
2. Lustgarten JS, Podos SM. Topical timolol and the nursing mother. Arch Ophthalmol. 1983;101:1381-2. PMID: 6615302
3. Madadi P, Koren G, Freeman DJ et al. Timolol concentrations in breast milk of a woman treated for glaucoma: calculation of neonatal exposure. J Glaucoma. 2008;17:329-31. PMID: 18552619
4. Fidler J, Smith V, de Swiet M. Excretion of oxprenolol and timolol in breast milk. Br J Obstet Gynaecol. 1983;90:961-5. PMID: 6626493
5. Boutroy MJ, Bianchetti G, Dubruc C et al. To nurse when receiving acebutolol: is it dangerous for the neonate? Eur J Clin Pharmacol. 1986;30:737-9. PMID: 3770068
6. Schimmel MS, Eidelman AI, Wilschanski MA et al. Toxic effects of atenolol consumed during breast feeding. J Pediatr. 1989;114:476-8. PMID: 2921694
7. Johnson SM, Martinez M, Freedman S. Management of glaucoma in pregnancy and lactation. Surv Ophthalmol. 2001;45:449-54. PMID: 11274697
8. Board JA, Fierro RJ, Wasserman AJ et al. Effects of alpha- and beta-adrenergic blocking agents on serum prolactin levels in women with hyperprolactinemia and galactorrhea. Am J Obstet Gynecol. 1977;127:285-7. PMID: 556882
Disclaimer: This material is provided for educational purposes only and is not intended for medical advice, diagnosis, or treatment. Consult your healthcare provider with any questions.
