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Influence of repetitive dosing of tetracyclines on biologic half‐life in serum
Author(s) -
Doluisio James T.,
Dittert Lewis W.
Publication year - 1969
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1002/cpt1969105690
Subject(s) - doxycycline , dosing , tetracycline , half life , tetracycline hydrochloride , pharmacokinetics , medicine , pharmacology , serum concentration , antibiotics , steady state (chemistry) , chemistry , biochemistry
The apparent biologic half‐lives of tetracycline, demethylchlortetracycline, methacycline, and doxycycline were found to increase from 6.3, 11, 7, and 8.3 hours to 10, 14.7, 11, and 14.5 hours, respectively, during 4 days of repetitive dosing (every 12 hours). Steady‐state serum levels predicted mathematically on the basis of the latter biologic half‐lives agreed with those observed experimentally, whereas steady‐state serum levels predicted on the basis of the biologic half‐life calculated from single‐dose studies did not. A method was developed for estimating the biologic half‐life from steady‐state serum level data; these estimates agreed well with the biologic half‐life estimated from semilogarithmic plots of serum level versus time data during the steady state and after dosing had ceased. Capsules of tetracycline phosphate complex, tablets of demethylchlortetracycline hydrochloride, capsules of methacycline hydrochloride, and capsules of doxycycline hyclate were found to produce comparable serum levels of antibiotic activity when administered at recommended doses every 12 hours.