Pharmacokinetics and pharmacodynamics can change a lot for different groups of people, like kids, older adults, and pregnant women. Here’s a simpler breakdown:

1. Kids (Pediatrics):

   • Babies, especially newborns, have underdeveloped livers and kidneys. This means they cannot clear some medicines from their bodies as well as adults can. For some drugs, they might only clear about 30% of what an adult can.
   • Babies may also have a larger space in their bodies for the medicine to spread out, so they often need doses based on their weight.

2. Older Adults (Geriatrics):

   • As people get older, their kidney function may decrease. This can slow down how quickly their bodies get rid of medicine by about 20-30%.
   • Older adults often take multiple medicines at the same time, which can increase the risk of side effects. In fact, nearly half of older adults may experience these unwanted reactions.

3. Pregnant Women:

   • During pregnancy, a woman's blood volume can increase by 40-50%. This change can affect how drugs spread in the body, so the amount needed may need to be adjusted.
   • The speed at which food and medicine move through the stomach may slow down, which can affect how well drugs are absorbed.

Knowing these differences is very important for giving safe and effective medicine to these special groups of people.