Drug metabolism in women: The effects of pregnancy, contraception, and hormone replacement therapy on drug response
Gender, age and hormones can all affect drug metabolism
It’s well-known that genetic variations inherited by individuals can lead to different reactions to medications, with the same drug dosage being safe and effective for one person but causing adverse reactions or being insufficient for another. This is known as pharmacogenetics. Clinical guidelines can help doctors select the optimal dose based on a person’s DNA profile. However, currently, these guidelines do not take into account the biological sex of a person. For females, drug prescribing needs to be more nuanced and consider their age, health status, and hormonal activity because pregnancy, contraception, and hormone replacement therapies can alter drug metabolism.
There is a complex interplay between an individual’s DNA, diet, and environmental factors, such as exposure to air pollution and pathogens, which can lead to changes in the activity of some enzymes involved in drug metabolism. These can impact the effectiveness of crucial medications such as antidepressants, sleep medications, antiepileptics, anti-acid drugs, and more.
For young women, certain hormonal contraceptives may pose unexpected health risks, including mood changes, and in rare cases, can lead to a stroke. Hormonal contraceptives can also alter sensitivity to coffee and the metabolism of some antidepressants and migraine medications.
During pregnancy, women may experience reduced effectiveness of ibuprofen (and similar medications) and a higher risk of side effects from antidepressants citalopram, escitalopram, and sertraline. However, these changes do not affect women who have inherently very low activity of the liver enzymes responsible for the metabolism of these medications. Conversely, women with rapid and normal metabolism are more susceptible to the effects of hormone-related changes in metabolism.
Age-related hormonal changes and reduction in liver function affect older women during menopause, leading to higher rates of depression. Hormone replacement therapy and other medications can also impact the effectiveness of antidepressants and other drugs. A recent study demonstrated that women over the age of 50 show progressively increasing blood levels of some antidepressants. Such age-related changes in drug metabolism can increase the risk of medication-induced side effects or reduced efficacy for drugs that have been working well for many years.
Understanding underlying genetic drug metabolism can help
Unfortunately, standard drug prescribing applications do not consider many of these factors, leaving patients at risk of side effects or inadequate therapy.
The Pillcheck medication optimization service provides a unique opportunity to better understand a person’s therapy in the context of their DNA, current state of health, and medication history. A pharmacogenetic profile can help doctors assess whether a specific drug is metabolized too slowly or fast.
Women experiencing depression, hot flashes, gastrointestinal problems, or medication-induced side effects may benefit from personalized medication optimization. Pillcheck offers a state-of-the-art pharmacogenetic panel optimized for the ethnically diverse Canadian population and a network of independent clinical pharmacists who have extensive experience in pharmacogenetics of psychiatry, pain management, and nutrition.
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