If digoxin has a half life of 35 hours
This means that it takes 35 hours for the concentration of digoxin in the body to decrease by half. The half-life of a drug is a measure of how long it takes for half of the drug to be eliminated from the body.
The half-life of a drug is the time it takes for the concentration of the drug in the body to decrease by half. In the case of digoxin, if the half-life is 35 hours, it means that after 35 hours, the concentration of digoxin in the body will be reduced by half.
To understand how the concentration of digoxin changes over time, you can use the concept of exponential decay. After each half-life, the drug concentration is halved, so you can continuously halve the concentration until it becomes negligible.
For example, if the initial concentration of digoxin in the body is 100 ng/mL, after 35 hours, it would be reduced to 50 ng/mL. After another 35 hours, it would be further reduced to 25 ng/mL, and so on.
It's important to note that it typically takes about 4-5 half-lives for a drug to be considered eliminated from the body. So in the case of digoxin with a half-life of 35 hours, it would take approximately 175 hours (or about 7 days) for most of the drug to be eliminated from the body.