Molecular Aspects of Geriatric Pharmacotherapy.

Pharmacotherapy in the geriatric population is one of the greatest challenges in modern medicine. Elderly patients, characterized by multimorbidity and the resulting polypharmacy, are significantly more exposed to adverse drug reactions (ADRs), which often lead to hospitalization and a decline in quality of life. Understanding the reasons for this difference requires an analysis of the physiological changes that occur during the aging process at the molecular level. This article presents a perspective on the molecular aspects of geriatric pharmacotherapy, focusing on the fundamental mechanisms that are modified with age. The analysis covers changes in pharmacokinetics, including the role and regulation of cytochrome P450 (CYP) enzymes, whose activity, especially in phase I reactions, is significantly reduced. The age-dependent dysfunction of drug transporters from the ABC (ATP-binding cassette) and SLC (solute carrier) families in key organs such as the intestines, liver and kidneys is discussed, which affects the absorption, distribution and elimination of xenobiotic compounds, including drugs. The article also provides a comprehensive analysis of the blood-brain barrier (BBB), describing changes in neurovascular integrity, including the dysfunction of tight junctions and a decrease in the activity of P-glycoprotein, sometimes referred to as multidrug resistance protein (MDR). This increases the susceptibility of the central nervous system to the penetration and action of drugs. In the realm of pharmacodynamics, changes in the density and sensitivity of key receptors (serotonergic, dopaminergic, adrenergic) are described based on neuroimaging data, explaining the molecular basis for increased sensitivity to certain drug classes, such as anticholinergics. The paper also explores new research perspectives, such as the role of the gut microbiome in modulating pharmacokinetics by influencing gene expression and the importance of pharmacoepigenetics, which dynamically regulates drug response throughout life via changes in DNA methylation and histone modifications. The clinical implications of these molecular changes are also discussed, emphasizing the potential of personalized medicine, including pharmacogenomics, in optimizing therapy and minimizing the risk of adverse reactions. Such an integrated approach, incorporating data from multiple fields (genomics, epigenomics, microbiomics) combined with a comprehensive geriatric assessment, appears to be the future of safe and effective pharmacotherapy in the aging population.