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The placental transfer of beta-adrenoceptor blocking agents has been well established in the last years. Randomized and/or controlled studies have given a less pessimistic view of the consequences of these drugs on the fetal and neonatal adaptation. In fact, the beta-blockers are able to produce hypotension, bradycardia, respiratory troubles in the newborn infant, troubles which are generally slight when the neonates are full-term. However, even if in good clinical conditions, this kind of neonate should be carefully monitored for at least the first 2 days of life.

The potential use of α-tocopherol (α-T) in the prevention of retrolental fibroplasia led to a study of the plasma kinetics of α-T. A dose of 20 mg α-tocopherol acetate (α-T-Ac) was injected subcutaneously in 5 premature newborns. α-T-Ac and α-T were assayed by high-pressure liquid chromatography. The maximum plasma concentration of α-T-Ac was 2.0 ± 0.60 mg/dl (x ± SEM). α-T concentrations remained above 0.5 mg/dl from 8 to 168 h with a mean peak plasma concentration of 2.15 ± 0.45 mg/dl. α-T-Ac absorption and elimination half-lives were 7.0 ± 0.7 and 23.2 ± 9.0 h. respectively; α-T appearance and elimination half-lives were 12.8 ± 3.1 and 80.6 ± 21.0 h. The proposed dosage to keep a plasma level higher than 0.5 mg/dl is 20 mg of α-T-Ac every 5 days.

Indomethacin (I) pharrnacokinetics was evaluated in 6 premature infants who received the drug for treatment of patent ductus arteriosus. Administered by oral or rectal route, I (0.2 mg/kg/24 h × 3) was promptly absorbed with peak plasma concentrations attained within 1 and 3 h, The elimination of I appeared to follow two compartment open model kinetics, with terminal plasma half-Jives ranging from 30 to 90 h. Apparent plasma clearance values were between 0.076 and 0.335 ml/min/kg. Ductal closure was observed in 4 of the 6 infants. Data point to a possible relationship between therapeu tic effects and I plasma concentrations.

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