The excretion of drugs is depending of three factors: the glomerular filtration rate (GFR), tubular secretion and tubular reabsorption of kidney. GFR depends on the body weight, sex, and creatinine level in the serum. Although the differences between men and women are taken into account by the inclusion of body weight in formulas, but always SKF is higher in women than in men. If one considers a body area, in women GFR on 10-25% is lower.
Excretion of drugs, which are allocated without changes in the urine, in women more slowly. For example, digoxin and methotrexate that excreting by the kidneys, according to their clearance in women on 13-17% slower. Women renal clearance is reduced of such medication as – aminoglycosides, cephalosporins, fluoroquinolones, vancomycin, anticonvulsant drug gabapentin (Gabagamy) and pregabalin (Lyrics). To account for the difference in excretion – doctors are prescribing drugs with lower doses, considering a glomerular filtration.
Pharmacology studies the mechanism of drug action, including physiological and biochemical effects on the body, the interaction between medicines concentration and pharmacological response. Therefore, depending on the blood concentration of the drug action is different, including the difference in efficacy or safety. There are some differences in the effect of medicines on women and men.
Antidepressants and antipsychotics.
On antidepressants and antipsychotics men and women respond differently. Although there is no difference in the severity of symptoms of depression, women are generally more responsive to treatment with SSRIs, especially to sertraline, compared with tricyclic antidepressants such as imipramine. Perhaps this phenomenon is due to the fact that in patients receiving SSRIs in women body is synthesized more tryptophan and less cortisol. Men, on the contrary, respond better to treatment TCAs than SSRIs.
Gender also affects the pharmacodynamics of neuroleptics. The onset and severity of symptoms are different in men and women, the men have more severe symptoms and longer hospital time stays. Women respond better to treatment by conventional antipsychotics, such as haloperidol and perphenazine, whereas men, compared with women, must get twice as high doses that needed to control symptoms. This is due to differences in medicines metabolism between the sexes.
Estrogens may affect on nerve tracts of pain, on pain perception and on response to some groups of medicines. As estrogen levels are much higher in women than in men, women have a lower pain threshold and increased pain response on standardized stimuli, also they have lower tolerance to pain. Women respond better to opioid analgesia. For achieve the same level of pain relief, men must get on 30-40% higher dose of morphine. Sex differences cause dimorphism of medicines in metabolism in the CNS or their effect on the cellular level. After injection of opioids, in women is higher the risk of severe sedation and respiratory depression.