Studies on Absorption and Distribution of Terramycin in Children

Abstract

The absorption of terramycin from the gastrointestinal tract is rather similar to that of aureomycin. Peak levels are low, tend to be achieved in 2 to 6 hours after ingestion, and are prolonged for several hours. Single oral doses of 11 mg/kg. body weight give peak serum levels ranging from 0.20 to 1.95 µg./cc., with a mean of 1.0 µg./cc. Doubling or tripling this single dose did not produce marked increases in serum levels. Dosage of 11 mg./kg. orally every six hours (44 mg./kg./24 hours) resulted in peak serum levels on the third day which were essentially identical with those after the initial dose. However, when a dosage of 33 mg./kg. was given orally every six hours (132 mg./kg./24 hours), marked cumulation in the serum was noted. The mean serum level on the first day on this schedule was 2.7 µg./cc., and on the third day, 8.0 µg./cc. Diffusion into the cerebrospinal fluid in three cases was poor. With spinal fluid and serum levels simultaneously obtained, the spinal fluid levels were ¼, ⅙ and ⅛, respectively of the serum levels. Intravenously administered terramycin in dosage of 6.6 mg./kg. gave peak serum levels at one-half hour, ranging from 10.0 to 12.8 µg./cc. Six hours after injection, serum levels ranged from 1.8 to 4.4 µg./cc., and at 12 hours, from 0.78 to 2.6 µg./cc. Terramycin given rectally in perforated capsules was well tolerated. However, in four patients given 66 mg./kg. by this route, peak serum levels ranged from 0 to 1.0 µg./cc. Recommended terramycin dosage: (a) Oral: 11 mg./kg./dose every six hours (44 mg./kg./24 hours). Adequate antibacterial serum levels for most susceptible organisms are produced with this dosage. Increasing the dosage to 33 mg./kg./dose every six hours (132 mg./kg./24 hours) may be done in cases when high serum levels seem indicated. (b) Intravenous: 6.6 to 11 mg./kg./dose every 6 to 8 hours.