Pharmacokinetics of the oral narcotic analgesic bezitramide and preliminary observations on its effect on experimentally induced pain.

Abstract

The oral absorption of bezitramide 5 mg was studied in 7 human volunteers, using a specific radioimmuno-assay which measured both bezitramide and its active metabolite R-4618. A lag time of 0.5-1.0 h and a Cmax of 5.4 ng/ml plasma were found, the latter occurring 2.5-3.5 h after administration. The apparent elimination half-life varied from 11 to 24 h. Less than 0.3% of the dose was excreted unchanged in the urine. High concentrations in the faeces of some individuals indicate incomplete absorption and/or biliary secretion. The analgesic effect, using a standardized superficial electrical stimulation method, reached its maximum between 2.5 and 3.5 h after dosing, in accordance with the absorption phase. The duration of the effect was highly variable. Experiments in rats (n = 6, 3H-bezitramide 2.5 micrograms), demonstrated extensive biliary excretion (up to 70% of total radioactivity) and less than 3% of the label was removed by urinary excretion.

• Authors: D K Meijer, G Hovinga, A Versluis, J Bröring, K van Aken, F Moolenaar, H Wesseling
• Journal: European journal of clinical pharmacology (Eur J Clin Pharmacol) Vol. 27 Issue 5 Pg. 615-8 ( 1984) ISSN: 0031-6970 [Print] Germany
• PMID: 6519169 (Publication Type: Journal Article)

Chemical References

• Analgesics
• Benzimidazoles
• bezitramide

Topics

• Adult
• Analgesics (metabolism, therapeutic use)
• Animals
• Benzimidazoles (metabolism, therapeutic use)
• Bile (metabolism)
• Electric Stimulation
• Humans
• Intestinal Absorption
• Kinetics
• Male
• Pain (drug therapy)
• Rats
• Rats, Inbred Strains
• Sensory Thresholds (drug effects)