Age changes how our bodies handle medicine, especially for young kids and older adults. This means doctors need to think carefully about how they prescribe drugs to these groups.

For Young Children:

1. Liver Development:

   • The liver gets better at processing medicines during the first year of life.
   • By the time a child is one year old, their liver can work almost like an adult's, but some parts still need time to mature. This can take until they're 2-5 years old.

2. Kidney Function:

   • The kidneys work hard to filter waste and this improves a lot in the first year.
   • By age 2, kids' kidney function is about 70-80% of what adults have.
   • Because of this, it's important to adjust medicine doses based on their body size.

For Older Adults:

1. Liver Function Decrease:

   • Starting around age 65, blood flow to the liver decreases by 30-40%. This affects how the liver breaks down medication.
   • About 15-20% of older people have liver problems that can change how they process drugs.

2. Kidney Function:

   • By age 75, kidney function can drop by up to 50%, which means their medicine doses may need to be lowered.
   • Common tests that show kidney function aren't always accurate for older folks because they often lose muscle mass.

In short, both young kids and older adults need special care when it comes to how they take medicines. The way their bodies process drugs changes with age, so doctors have to adjust their prescriptions accordingly.