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Deficient C-oxidation of nicotine
N L Benowitz1, P Jacob, D P Sachs
1Clinical Pharmacology Unit, San Francisco General Hospital Medical Center, CA 94110, USA.
Clinical Pharmacology and Therapeutics
|May 1, 1995
Summary
This study identifies the first person with deficient nicotine C-oxidation, leading to a longer nicotine half-life and reduced cotinine generation. This metabolic difference may impact tobacco use risks and addiction potential.
Area of Science:
- Pharmacokinetics
- Metabolism
- Toxicology
Background:
- Nicotine is primarily metabolized to cotinine via C-oxidation in most individuals.
- Understanding nicotine metabolism is crucial for assessing tobacco use risks and addiction.
Observation:
- A clinical trial participant exhibited expected nicotine levels but unusually low cotinine levels.
- This pattern persisted despite both cigarette smoking and transdermal nicotine administration.
Findings:
- The index case subject displayed significantly reduced nicotine clearance (6.5 ml/min/kg vs. 17.2 ml/min/kg) and a prolonged nicotine half-life (348 min vs. 138 min).
- Nicotine conversion to cotinine was markedly deficient (9% vs. 72% in controls).
- Cotinine clearance was within the normal range, indicating a specific defect in nicotine C-oxidation.
Implications:
- This is the first documented case of deficient nicotine C-oxidation.
- This metabolic anomaly is linked to prolonged nicotine exposure and reduced cotinine formation.
- Altered nicotine metabolism may influence the addictive properties and health risks associated with tobacco consumption.