Interactions between alcohol and gastric metabolizing enzymes: practical implications.

Area of Science:

• Pharmacology
• Gastroenterology
• Toxicology

Background:

• A portion of ingested alcohol undergoes gastric oxidation (first-pass metabolism) rather than entering systemic circulation.
• This gastric metabolism of ethanol is influenced by factors including gender, alcohol consumption history, and gastric surgery.
• Certain medications can significantly alter the rate of first-pass ethanol metabolism.

Purpose of the Study:

• To review the effects of H2-receptor antagonists on blood ethanol levels.
• To understand how drug interactions influence alcohol metabolism.
• To discuss the clinical and medicolegal implications of altered alcohol metabolism.

Main Methods:

• Review of studies investigating the impact of H2-receptor antagonists on blood ethanol concentrations.
• Analysis of factors affecting gastric alcohol dehydrogenase activity.
• Examination of clinical data related to drug-induced changes in alcohol absorption.

Main Results:

• First-pass metabolism of ethanol is minimal when fasting and lower in women than men, and in alcoholics compared to non-alcoholics.
• Gastric ethanol oxidation is abolished after subtotal gastrectomy.
• H2-receptor antagonists, specifically cimetidine and nizatidine, were found to inhibit gastric ethanol oxidation, leading to higher blood alcohol levels.

Conclusions:

• H2-receptor antagonists can inhibit gastric alcohol metabolism, increasing systemic alcohol levels.
• This interaction has significant clinical implications for patients taking these medications and consuming alcohol.
• Understanding these effects is crucial for medicolegal contexts involving alcohol consumption and medication use.