Treating elderly is an issue - clinical trials use young, healthy test subjects
Only limited data is available on how different drugs affect and interact with each other in elderly.
This is problematic as elderly often have multiple diseases therefore are on multiple medication.
Also the correct dosage for the elderly might different than the dosage decided by clinical trials.
Older people also have kidney and liver issues that may alter drug metabolism inside their bodies.
It's important to carry out clinical trials in older people and in those with multiple health problems.