Final answer:
When a drug is administered, it becomes available to body fluids and tissues, and this availability is influenced by factors such as blood flow, drug affinity for tissue, dose, and concentration.
Step-by-step explanation:
When a drug is administered, it becomes available to body fluids and tissues. The availability of a drug in the body is influenced by several factors, including blood flow, drug affinity for tissue, dose, and concentration. If a drug has a high affinity for a specific tissue, it is more likely to accumulate in that tissue. Similarly, a higher dose or concentration of a drug can increase its availability in body fluids and tissues. For example, if a drug has a high affinity for liver tissue and is administered at a high dose, it may accumulate in the liver and have a stronger effect on liver function compared to other tissues in the body.