Sex-Specific Medication Response in Multimorbidity: Clinical Implications and Evidence-Based Review

Abstract

Sex-specific differences in medication response among patients with multimorbidity represent a critical, yet often underappreciated, aspect of personalized medicine. This review synthesizes recent evidence on how biological sex influences pharmacokinetics, pharmacodynamics, and clinical outcomes in the context of multiple coexisting chronic diseases. Drawing upon large-scale epidemiological studies and guideline-based recommendations, we elucidate mechanisms underlying sex-based variability in drug efficacy and adverse effects, highlight practical implications for prescribing in complex patients, and discuss future directions for research and clinical practice. The findings underscore the necessity for a sex-informed approach to multimorbidity management to optimize therapeutic outcomes and minimize risks.

Introduction

Multimorbidity, defined as the co-occurrence of two or more chronic health conditions, poses significant challenges for healthcare systems globally. The complexity of managing multiple diseases concurrently is further compounded by sex-specific physiological and pharmacological differences that impact medication response. Despite mounting evidence of sex-based disparities in drug metabolism, efficacy, and safety, clinical guidelines and therapeutic regimens often neglect these critical distinctions. This article aims to provide an in-depth, evidence-based analysis of sex-specific medication responses in multimorbid patients, emphasizing mechanisms, clinical impact, and implications for practice.

Epidemiology / Disease Burden

Multimorbidity prevalence escalates with age, affecting approximately two-thirds of adults over 65 years, with higher rates observed in women than men. Sex differences extend beyond prevalence; women tend to develop multimorbidity at younger ages and accumulate a greater number of chronic conditions over time. Epidemiological data indicate that women are more likely to experience musculoskeletal disorders, depression, and autoimmune diseases, while men more commonly present with cardiovascular and metabolic diseases. Such variations influence medication selection, dosing, and risk of drug-drug interactions, making sex-specific consideration essential in clinical decision-making.

Pathophysiology

Sex-related biological differences arise from both genetic (sex chromosomes) and hormonal (estrogen, progesterone, testosterone) influences, affecting organ function, immune response, and disease trajectories. These differences alter pharmacokinetics absorption, distribution, metabolism, and elimination of drugs and pharmacodynamics, including receptor sensitivity and intracellular signaling. For example, estrogen modulates hepatic enzyme activity, impacting metabolism of drugs such as statins, beta-blockers, and certain antidepressants. Conversely, androgen levels may influence renal clearance and cardiovascular drug response in men. These mechanistic insights are crucial for anticipating variable drug effects in multimorbid patients.

Risk Factors

Sex interacts with other risk factors such as age, body composition, genetics, and comorbidities to modulate medication response in multimorbidity. Polypharmacy a common consequence of multimorbidity increases the likelihood of adverse drug reactions, with women at higher risk due to differences in body fat percentage, gastric motility, and enzyme activity. Additionally, sociocultural determinants, including access to healthcare and medication adherence, may differ by sex, further influencing clinical outcomes. Recognizing these intertwined risk factors is fundamental to individualized pharmacotherapy.

Clinical Features

Sex-specific medication responses manifest in diverse clinical presentations. Women are more susceptible to drug-induced QT prolongation, leading to higher rates of torsades de pointes with certain antiarrhythmics and psychotropics. Men may experience more pronounced blood pressure reductions with ACE inhibitors but are less vulnerable to statin-associated myopathies, which disproportionately affect women. Furthermore, adverse drug reactions are reported up to 50% more frequently in women, particularly for medications affecting the central nervous system and cardiovascular system. These features necessitate vigilant monitoring and tailored therapy in multimorbid populations.

Diagnosis

Diagnosing adverse drug reactions and suboptimal therapeutic responses in multimorbidity requires a high index of suspicion and a sex-sensitive lens. Routine pharmacovigilance should incorporate sex-stratified assessment tools and biomarkers. For example, women may exhibit atypical symptomatology in myocardial infarction or statin intolerance, complicating diagnosis and management. Incorporating sex-based reference ranges for laboratory values and diagnostic thresholds can improve detection and guide safer prescribing.

Treatment & Management

Optimal management of multimorbid patients necessitates individualized regimens that account for sex-specific pharmacological differences. Dose adjustment based on body weight, renal function, and hormonal status may reduce adverse events. Clinicians should prioritize medications with favorable safety profiles in the context of polypharmacy, especially in women at higher risk for drug interactions. Shared decision-making, patient education, and regular medication reviews are essential components of sex-sensitive care. Moreover, deprescribing strategies should be tailored to minimize unnecessary medications while considering sex-specific benefits and harms.

Recent Advances / Emerging Therapies

Recent advances in pharmacogenomics have revealed sex-linked genetic polymorphisms that influence drug metabolism, such as CYP450 enzyme variants. Emerging therapies increasingly incorporate sex as a stratification variable in clinical trials, providing more granular data on efficacy and safety. Novel drug delivery systems, including transdermal patches and long-acting injectables, offer alternative options for patients with sex-specific absorption or metabolism profiles. Integration of real-world data and machine learning holds promise for refining predictive models of drug response in multimorbid, sex-diverse populations.

Guideline Recommendations

Major clinical guidelines, such as those from the American College of Cardiology and European Society of Hypertension, now acknowledge sex differences in disease risk and therapeutic response. However, implementation remains inconsistent. Recommendations increasingly call for sex-specific dosing, monitoring, and risk stratification, particularly for cardiovascular, psychotropic, and anticoagulant therapies. Multidisciplinary collaboration and continuing medical education are necessary to translate these recommendations into routine practice, ultimately improving outcomes for multimorbid patients of both sexes.

Conclusion

Sex-specific medication response in multimorbidity is a complex interplay of biological, pharmacological, and sociocultural factors that significantly impact clinical care. Recognizing and addressing these differences is critical for optimizing therapeutic efficacy, minimizing adverse effects, and advancing personalized medicine. Ongoing research, guideline refinement, and clinician education are essential to bridge knowledge gaps and ensure equitable, evidence-based treatment for all patients with multimorbidity.