The difference in weight does not always explain the difference in response to medications. Physiological differences also have an influence, so that it is not always enough to adapt the dose to body weight.
Women experience significantly more adverse drug reactions than men. This is highlighted by data from a large review, which show a 50% to 75% higher risk of side effects in women, including adverse rashes and gastrointestinal events. The reasons for this increased risk are not fully known, however, but a new study published in Communication Nature shed light on what differences may account for different drug responses between men and women, rejecting the idea that the disparity in drug response is solely due to different body weight. This basic assumption in biomedicine, the authors of the publication point out, is unsupported for most traits of an individual, such as glucose levels. Therefore, side effects of drugs in women are unlikely to be mitigated simply by adjusting the dose to body weight.
Side effects are more common in women
The differences in side effects, says Professor Laura Wilson, the study’s first author and correspondent, are strongly related to what the drug does or doesn’t do in the bodies of women and men. Besides these different effects, there are also many differences in physiology between men and women, which relate to how drugs are absorbed and eliminated by the body, but not body weight. ” To check this – points out Wilson, who is a professor of evolutionary and synthetic biology at the University of New South Wales in Sydney, Australia – , we borrowed a method commonly used in evolutionary biology, known as “allometry”, in which a relationship between a trait of interest and body size is examined on a logarithmic scale”.
The investigation, detailed in an article on La conversationexamined allometric analyzes of 363 preclinical traits in male and female mice, including more than 2 million measurements from the International Mouse Phenotyping Consortium. ” We focused on one of the most common animal disease models, asking whether sex differences in preclinical traits – such as fat mass, glucose and LDL cholesterol levels – could be explained by body weight alone. – adds the expert – . Our analyzes revealed sex differences in many traits that cannot be explained by different body weights. Some examples are physiological traits, such as iron levels and body temperature, morphological traits such as lean body mass and fat mass, and cardiac traits such as heart rate variability.”.
In particular, the researchers found that the relationship between a trait and body weight varied significantly across all parameters examined, indicating that the differences between men and women cannot be generalized. ” Females aren’t just smaller versions of males – emphasizes Wilson – . Our study reveals that males and females are different in many preclinical traits, suggesting that drug response is likely to be different between the two sexes and indicating that biomedical research needs to focus more closely on measuring how and how the sexes differ.”.
At a time when personalized medicine interventions are within reach and patient-specific solutions represent a possible frontier, researchers therefore emphasize the need for new comparative studies to explain the characteristics of the differences between men and women. ” In this direction Wilson a conclu. the methods of our study may help clarify the nature of these differences and provide a pathway to reduce drug reactions”.