Single-dose kinetics and bioavailability of ketobemidone

Area of Science:

• Pharmacokinetics
• Clinical Pharmacology

Background:

• Ketobemidone is an analgesic medication used for pain management.
• Understanding its absorption and elimination is crucial for optimizing therapeutic use, especially in post-surgical patients.

Purpose of the Study:

• To investigate the single-dose pharmacokinetics and bioavailability of ketobemidone via oral, rectal, and intravenous routes.
• To compare ketobemidone's elimination profile across different administration methods.

Main Methods:

• Pharmacokinetic analysis of ketobemidone in post-surgical patients.
• Intravenous, oral, and rectal administration of Ketogin (containing ketobemidone).
• Plasma concentration determination using gas chromatography-mass spectrometry with a deuterated internal standard.

Main Results:

• Ketobemidone demonstrated rapid plasma disappearance after intravenous and oral administration, with a mean half-life of 2.25–2.45 hours.
• Rectal administration resulted in a slightly prolonged plasma half-life (3.27 hours), likely due to delayed absorption.
• Oral bioavailability was 34% ± 16% and rectal bioavailability was 44% ± 9%.

Conclusions:

• Ketobemidone is rapidly eliminated following intravenous, oral, and rectal administration.
• Rectal administration shows a slightly higher bioavailability and a prolonged half-life compared to oral administration.
• These findings provide valuable data for the clinical application of ketobemidone, particularly regarding its pharmacokinetic profile.