Did you know that men and women react differently to the same chemicals in medicines? This is an important discovery because these differences influence the treatment of the same disease in both sexes. Why do men and women respond to medications differently?

Did you know thata woman reacts to medication differently than a man ? That she should takeother doses of drugs ? Women and men should not be treated in the same way because, due to the physical differences between the sexes, they respond differently to medications. Surprisingly, this "obvious obviousness" has been talked about loudly only recently. Why?

Until 1993 drugs were not tested on women

Until 1993, women had not participated in clinical trials of new drugs. It was dictated by researchers' concern for the he alth of women and their children. However, clinical observations have shown that women who are treated with the same drugs as men (identical doses, time of administration, the same disease), tolerate the therapy differently and its effects are different. The US Food and Drug Administration (FDA) was the first to authorize the participation of women in clinical trials (in 1993). She recommended that researchers pay special attention to:

  • influence of the menstrual cycle and menopause on the pharmacokinetics of drugs, i.e. changes in their concentration in the organism
  • which occur at certain intervals after taking the preparation
  • influence of estrogens, oral contraceptives and drugs used in hormone replacement therapy on the effects of other drugs
  • influence of oral contraceptives on the effectiveness of the drug under evaluation

The results of the first clinical trials of drugs involving women were so significant that a few years later no drug could be registered if no women participated in the research on its effects.

Why the difference in response to the drug between a woman and a man?

Each ingested drug, both in the body of a woman and a man, undergoes the same processes, which include:

  • absorption of the active substance,
  • distributing it in the body,
  • metabolism,
  • expulsion.

In the study "The effect of gender on the pharmacokinetics of selected drugs" conducted at the Faculty of PharmacyThe Medical University of Gdańsk has proven that gender differences appear already at the stage of drug absorption. It is similar in the subsequent stages of the passage of the drug through the body.

This is not only because other hormones play a major role in our bodies, but also because we have a different physique and metabolism. Thus, gender differences may affect how the same disease is treated and how the body responds differently to taking the same medications.

Drug absorption and body composition

Men usually have more muscle mass, so the dose of a drug, e.g. an antibiotic, must be correspondingly higher than for women. But it's not just your body weight that matters. A woman's body has more adipose tissue to absorb the drug molecules, so the concentration in the blood will be lower than that of a man. In the case of drugs acting on the central nervous system, it is important that although women have less blood in the body than men, women flow much faster. As a result - the drug will reach its destination faster.

Men have a much longer gastrointestinal tract than women, so the absorption of the drug given at the same time and dose will start later. In women, the delayed effect of medicines taken by mouth is due to the fact that food moves more slowly from the stomach into the small intestine, which has the greatest ability to absorb all substances in the body. The time it takes for the food to pass into the intestine is therefore decisive for the delayed action of the drug.

Drug absorption and the hormone cycle

We know that sex hormones have a huge impact on the appearance and well-being of a woman. But by acting on individual organs, they also determine the effectiveness of treatment. Before menstruation, a woman's body retains water, which lowers the concentration of water-soluble drugs in the blood. During the same period of the cycle, a woman's body produces less gastric juice, so she will react less to barbiturates (hypnotics) because less of the active substance will be absorbed.

The same will be true with anesthetics or anti-epileptic drugs. Men will respond faster and more effectively to these medications. But in the same period of the cycle, women will respond better to antidepressants as they are weak alkalis and with little gastric juice they will be better absorbed. After ovulation (in the luteal phase), the absorption time of drugs in the small intestine is significantly prolonged because progesterone relaxes smooth muscles.

Drug toxicity is increased by enzymes and hormones

Hormonesthey also determine that women are more exposed to the toxic effects of drugs than men. This is due to testosterone - a hormone that women of childbearing age have about 20 times less than men. Why is it so important? Testosterone stimulates liver enzymes to work more actively, which accelerate the metabolism of drugs and their excretion. The high level of estrogen in the female body reduces the concentration of a certain protein, which determines the absorption of drugs.

The metabolism of drugs is achieved by enzymes produced in the liver and intestines. In men, they are more efficient and remove metabolites, i.e. compounds formed as a result of a chemical reaction in the body between a drug and compounds produced by cells, from the body faster. In a woman, enzymes work more slowly, so the remnants of drug metabolism stay longer in her body.

Different pace of work of internal organs

Women's kidneys work by 10 percent slower than men, which has a huge impact on the speed of elimination of drug residues. But this is not because of a hormonal difference, but because of the lower body weight of women. Therefore, if glomerular filtration is slower, the high concentration of the active substance in the drug lasts longer in women than in men.

Further research into the treatment of women and men

In the prevention of heart attacks and strokes, it is commonly recommended to take appropriate doses of acetylsalicylic acid. It turns out, however, that its preventive action is different in women than in men: women protect against stroke, and men against heart attack. Although the results of research that led American scientists to such conclusions were protested in Europe, they also prompted scientists to start research into how various active substances affect the female body and how - the male body. Work is currently underway to determine the effects of paracetamol and a new generation of non-steroidal anti-inflammatory drugs on both sexes. It is already known that in people with slow metabolism, i.e. also in women, drugs from these groups should be administered in smaller doses.

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