Abstract
Blood concentrations of promethazine and promethazine sulphoxide have been measured following oral and intravenous administration of promethazine to seven healthy male volunteers. Promethazine disposition is characterised by a large volume of distribution (1970 1) and a high blood clearance (1.141 min-1). Less than 1% of the dose is excreted unchanged in the urine, therefore total body clearance is essentially metabolic clearance. In accord with this high clearance the oral availability of promethazine is only 25%. The absorption of promethazine from the gastrointestinal tract exceeds 80% in most subjects. Minimal metabolism by the gastrointestinal mucosa is implicated. Promethazine sulphoxide pharmacokinetics are consistent with a pronounced first pass effect. Although the area under the curve for this metabolite is not route dependent, there is a marked alteration in the shape of the metabolite curve when oral and intravenous data are compared. Evidence is presented to support the hypothesis that S-oxidation of promethazine is predominantly an hepatic event. The conclusions of previous investigators with regard to the role of the gut mucosa in S-oxidation of phenothiazines is critically assessed.
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- Alván G., Borga O., Lind M., Palmér L., Siwers B. First pass hydroxylation of nortriptyline: concentrations of parent drug and major metabolites in plasma. Eur J Clin Pharmacol. 1977 Mar 11;11(3):219–224. doi: 10.1007/BF00606414. [DOI] [PubMed] [Google Scholar]
- Benet L. Z., Galeazzi R. L. Noncompartmental determination of the steady-state volume of distribution. J Pharm Sci. 1979 Aug;68(8):1071–1074. doi: 10.1002/jps.2600680845. [DOI] [PubMed] [Google Scholar]
- Cooper T. B. Plasma level monitoring of antipsychotic drugs. Clin Pharmacokinet. 1978 Jan-Feb;3(1):14–38. doi: 10.2165/00003088-197803010-00002. [DOI] [PubMed] [Google Scholar]
- Curry S. H., D'Mello A., Mould G. P. Destruction of chlorpromazine during absorption in the rat in vivo and in vitro. Br J Pharmacol. 1971 Jul;42(3):403–411. doi: 10.1111/j.1476-5381.1971.tb07125.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dahl S. G. Pharmacokinetics of methotrimeprazine after single and multiple doses. Clin Pharmacol Ther. 1976 Apr;19(4):435–442. doi: 10.1002/cpt1976194435. [DOI] [PubMed] [Google Scholar]
- Dahl S. G., Strandjord R. E. Pharmacokinetics of chlorpromazine after single and chronic dosage. Clin Pharmacol Ther. 1977 Apr;21(4):437–448. doi: 10.1002/cpt1977214437. [DOI] [PubMed] [Google Scholar]
- DiGregorio G. J., Ruch E. Human whole blood and parotid saliva concentrations of oral and intramuscular promethazine. J Pharm Sci. 1980 Dec;69(12):1457–1459. doi: 10.1002/jps.2600691234. [DOI] [PubMed] [Google Scholar]
- Eggert Hansen C., Rosted Christensen T., Elley J., Bolvig Hansen L., Kragh-Sorensen P., Larsen N. E., Naestoft J., Hvidberg E. F. Clinical pharmacokinetic studies of perphenazine. Br J Clin Pharmacol. 1976 Oct;3(5):915–923. doi: 10.1111/j.1365-2125.1976.tb00647.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gram L. F., Christiansen J. First-pass metabolism of imipramine in man. Clin Pharmacol Ther. 1975 May;17(5):555–563. doi: 10.1002/cpt1975175555. [DOI] [PubMed] [Google Scholar]
- Houston J. B. Drug metabolite kinetics. Pharmacol Ther. 1981;15(3):521–552. doi: 10.1016/0163-7258(81)90056-5. [DOI] [PubMed] [Google Scholar]
- Kriegelstein J., Lier F., Michaelis J. Albumin binding and hydrophobic character of promazine and chlorpromazine metabolites. Naunyn Schmiedebergs Arch Pharmacol. 1972;272(2):121–130. doi: 10.1007/BF00508763. [DOI] [PubMed] [Google Scholar]
- Lader M. Monitoring plasma concentrations of neuroleptics. Pharmakopsychiatr Neuropsychopharmakol. 1976 Jul;9(4):170–177. doi: 10.1055/s-0028-1094491. [DOI] [PubMed] [Google Scholar]
- Taylor G., Houston J. B. Simultaneous determination of promethazine and two of its circulating metabolites by high-performance liquid chromatography. J Chromatogr. 1982 Jun 11;230(1):194–198. doi: 10.1016/s0378-4347(00)81449-8. [DOI] [PubMed] [Google Scholar]
- Walle T., Conradi E. C., Walle U. K., Fagan T. C., Gaffney T. E. 4-Hydroxypropranolol and its glucuronide after single and long-term doses of propranolol. Clin Pharmacol Ther. 1980 Jan;27(1):22–31. doi: 10.1038/clpt.1980.4. [DOI] [PubMed] [Google Scholar]