CARTEOLOL

Fetal Risk Summary

Carteolol is a nonselective b1, b2-adrenergic blocking agent used in the treatment of hypertension and topically in the therapy of glaucoma. No teratogenic effects were observed in pregnant mice and rabbits treated with doses much higher than the maximum recommended human dose (1,2 and 3). A dose-related increase in the incidence of wavy ribs was noted in fetal rats whose mothers were given doses 212 times the maximum recommended human dose (MRHD) (3). Fetotoxicity (increased resorptions and decreased fetal weight) was observed in rats and rabbits at doses up to 5264 and 1052 times the MRHD (3). These effects were not noted in mice at doses up to 1052 times the MRHD (3).

No studies describing the use of carteolol in human pregnancies have been located. If used near delivery, the newborn infant should be closely observed 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.

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 then 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.

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

Breast Feeding Summary

Carteolol is excreted into the milk of lactating rats (3), but studies measuring the amount of the drug in human milk, or the use of the drug by women nursing infants, have not been located. If carteolol is 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.

References

1. Tanaka N, Shingai F, Tamagawa M, Nakatsu I. Reproductive study of carteolol hydrochloride in mice, part 1. Fertility and reproductive performance. J Toxicol Sci 1979;4:47–58. As cited in Shepard TH. Catalog of Teratogenic Agents. 6th ed. Baltimore, MD:Johns Hopkins University Press, 1989:119.
2. Tamagawa, M, Namoto T, Tanaka N, Hishino H. Reproduction study of carteolol hydrochloride in mice, part 2. Perinatal and postnatal toxicity. J Toxicol Sci 1979;4:59–78. As cited in Shepard TH. Catalog of Teratogenic Agents. 6th ed. Baltimore, MD:Johns Hopkins University Press, 1989:119.
3. Product information. Cartrol. Abbott Laboratories, 1997.