Amoxicillin pharmacokinetics in preterm infants with gestational ages of less than 32 weeks.

The multiple-dose pharmacokinetics of amoxicillin (AM [administered twice daily in a 25-mg/kg of body weight intravenous dose]) in 17 preterm infants (11 males; gestational age, 29 +/- 1.9 weeks; birth weight, 1,175 +/- 278 g) were evaluated on day 3 of life. Blood samples were collected from an arterial catheter at 0, 0.5, 1, 2, 4, 8, and 12 h after the intravenous dose. A high-performance liquid chromatography method was used to determine AM concentrations in serum. AM pharmacokinetics followed a one-compartment open model. The glomerular filtration rates of all patients were simultaneously studied by means of the 24-h continuous inulin infusion technique. The elimination half-life, apparent volume of distribution, and total body clearance of AM (mean +/- standard deviation) were 6.7 +/- 1.7 h, 584 +/- 173 ml, and 62.4 +/- 23.3 ml/h, respectively. The mean (+/- standard deviation) AM peak and trough levels were 53.6 +/- 9.1 and 16.0 +/- 4.9 mg/liter, respectively. All infants had a serum trough level above 5 mg/liter. The total body clearance and apparent volume of distribution of AM and the clearance of inulin increased significantly with increasing gestational age. The total body clearance of AM (1.0 +/- 0.4 ml/min) and the clearance of inulin (1.0 +/- 0.3 ml/min) were similar. The total body clearance of AM increased significantly with increasing clearance of inulin. We conclude that an AM dose of 25 mg/kg every 12 h given to preterm infants in the first week of life with gestational ages of less than 32 weeks results in serum levels well above the MIC for major microorganisms involved in neonatal infections.

An outbreak of thyrotoxicosis due to atypical subacute thyroiditis.

We describe an epidemic of self-limited (6 weeks) thyrotoxicosis which affected 12 index cases, 5 household contacts, and 6 retrospectively identified cases in July, August, and September, 1987 in the town of Winterswijk (28,011 inhabitants), The Netherlands. A small goiter was present in 9 of the 12 index patients, tender upon palpation in only 2. Signs and symptoms of thyrotoxicosis were accompanied by a low grade fever in combination with fatigue, headache, myalgia, and a fine desquamation of the palms and soles. The apparent incubation time between family members was 6 days. Thyroid technetium uptake was decreased in 10 of 11 tested patients. Laboratory findings included elevated sedimentation rates (up to 68 mm/h), increased liver enzymes, lymphopenia in 2 patients, and absence of thyroid autoantibodies. HLA-B35, associated with classical subacute thyroiditis, was found in 1 patient only. An etiological agent was not identified. No evidence was found for thyrotoxicosis factitia. After 10 months, all patients were euthyroid, without a goiter or thyroid autoantibodies. Thus, a new variant of thyroiditis, atypical subacute thyroiditis, was probably the cause of this unusual outbreak. It is unclear at present if this variant of thyroiditis is common in communities and represents a separate disease entity.