Alcohol – What Not to Mix with Alcohol: Essential Knowledge

Contemporary developed societies exhibit a marked upward trend in the consumption of pharmaceutical preparations and dietary supplements, substances that—akin to nutrients—undergo enzymatic biotransformation within the body prior to eventual excretion. Of paramount clinical significance, however, are the metabolic conversion phases during which the most frequent interactions with food components occur. This sequential process encompasses the liberation of the active compound from its dosage form, transmembrane absorption into systemic circulation, distribution to target tissues, metabolic modifications—primarily catalyzed by cytochrome P-450 isoenzymes (CYP450) localized predominantly in the liver but also present in the small intestine, lungs, and kidneys—and ultimate elimination. Parallel metabolic and detoxification pathways apply to ethanol, whose catabolism is initiated by alcohol dehydrogenase (ADH) in the stomach (converting 70–90% of ethanol to acetaldehyde) and CYP2E1 in the liver (oxidizing acetaldehyde to acetic acid). The accumulation of this toxic intermediate, acetaldehyde, is directly responsible for the hallmark symptoms of alcohol withdrawal syndrome, including cephalalgia, nausea, vertigo, and hypotension. A critical clinical concern arises from the fact that commonly used over-the-counter medications (e.g., acetylsalicylic acid, H₂-receptor antagonists) inhibit ADH activity, thereby prolonging blood alcohol clearance times. Even more hazardous are interactions with aldehyde dehydrogenase (ALDH) inhibitors, which precipitate acetaldehyde buildup—examples include certain cytostatic agents (procarbazine), nitrofurans (nifuroxazide in diarrhea treatment), and furagins (for urinary tract infections). Of particular danger is the concomitant use of paracetamol and alcohol due to the risk of progressive hepatocyte necrosis, exacerbated by the synergistic induction of CYP2E1. Additionally, central nervous system-active substances (e.g., benzodiazepines) exhibit altered pharmacokinetic profiles under ethanol influence: acute alcohol intake competes for metabolic enzymes, leading to toxicity, whereas chronic abuse accelerates drug clearance via CYP450 induction, thereby diminishing therapeutic efficacy. Equally noteworthy is the interaction between alcohol and retinol (vitamin A), which may result in severe hepatic damage following prolonged co-exposure.