BETAXOLOL

Fetal Risk Summary

Betaxolol is a cardioselective b1-adrenergic blocking agent used in the treatment of hypertension and topically in the therapy of glaucoma. Betaxolol is teratogenic in rats producing skeletal and visceral anomalies at maternally toxic doses (600 times the maximum recommended human dose [MRHD]) (1). At this dose, postimplantation loss and reduced litter size and weight were also noted. At doses 6 and 60 times the MRHD, a possible increased incidence of incomplete descent of testes and sternebral reductions were observed (1). No teratogenic effects were observed in rabbits, but an increase in postimplantation loss occurred at the highest dose tested (54 times the MRHD) (1).

No reports describing the use of betaxolol in human pregnancy have been located. Some b-blockers may cause intrauterine growth retardation and reduced placental weight (e.g., see Atenolol and Propranolol). Treatment beginning early in the 2nd trimester results in the greatest weight reductions. This toxicity has not been consistently demonstrated in other agents within this class, but the relatively few pharmacologic differences among the drugs suggest that the reduction in fetal and placental weights probably occurs with all at some point. The lack of toxicity documentation may reflect the number and type of patients studied, the duration of therapy, or the dosage used, rather than a true difference among b-blockers. Although growth retardation is a serious concern, the benefits of maternal therapy with b-blockers may, in some cases, outweigh the risks to the fetus and must be judged on a case-by-case basis.

If used near delivery, the newborn infant should be closely monitored for 24 - 48 hours for signs and symptoms of b-blockade. Long-term effects of in utero exposure to b-blockers have not been studied but warrant evaluation.

[*Risk Factor D if used in 2nd or 3rd trimesters.]

Breast Feeding Summary

Betaxolol is excreted into human milk in quantities sufficient to produce b-blockade in a nursing infant (1). No reports have been located that describe the use of this agent during nursing. If used during nursing, the infant should be closely observed for hypotension, bradycardia, and other signs or symptoms of b-blockade. Long-term effects of exposure to b-blockers from milk have not been studied but warrant evaluation.

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