Acebutolol Hydrochloride

Contraindications

CONTRAINDICATIONS Acebutolol hydrochloride capsules are contraindicated in: 1) persistently severe bradycardia; 2) second- and third-degree heart block; 3) overt cardiac failure; and 4) cardiogenic shock. (See WARNINGS .)

Pregnancy & Breastfeeding

Pregnancy Teratogenic Effects Reproduction studies have been performed with acebutolol in rats (up to 630 mg/kg/day) and rabbits (up to 135 mg/kg/day). These doses are equivalent to approximately 31.5 and 6.8 times the maximum recommended therapeutic dose in a 60-kg human, respectively. The compound was not teratogenic in either species. In the rabbit, however, doses of 135 mg/kg/day caused slight fetal growth retardation; this effect was considered to be a result of maternal toxicity, as evidenced by reduced food intake, a lowered rate of body weight gain, and mortality. Studies have also been performed in these species with diacetolol (at doses of up to 450 mg/kg/day in rabbits and up to 1800 mg/kg/day in rats). Other than a significant elevation in post-implantation loss with 450 mg/kg/day diacetolol, a level at which food consumption and body weight gain were reduced in rabbit dams and a nonstatistically significant increase in incidence of bilateral cataract in rat fetuses from dams treated with 1800 mg/kg/day diacetolol, there was no evidence of harm to the fetus. There are no adequate and well-controlled trials in pregnant women. Because animal teratology studies are not always predictive of the human response, acebutolol should be used during pregnancy only if the potential benefit justifies the risk to the fetus. Non–Teratogenic Effects Studies in humans have shown that both acebutolol and diacetolol cross the placenta. Neonates of mothers who have received acebutolol during pregnancy have reduced birth weight, decreased blood pressure, and decreased heart rate. In the newborn the elimination half-life of acebutolol was 6 to 14 hours, while the half-life of diacetolol was 24 to 30 hours for the first 24 hours after birth, followed by a half-life of 12 to 16 hours. Adequate facilities for monitoring these infants at birth should be available.