Drug excretion is an important part of how our bodies handle medicine. After a medicine does its job, it needs to be removed from the body. There are three main ways this happens: through the kidneys, bile, and lungs.
The kidneys play a big role in getting rid of drugs. This happens in three main steps:
Glomerular Filtration: This is where drugs get filtered out of the blood in a part of the kidney called the glomerulus. Only drugs that aren’t attached to proteins can be filtered out.
Tubular Secretion: In this step, which happens in a part of the kidney called the proximal tubule, some drugs are actively pushed into the urine. Special helpers called transporters help with this. For example, penicillin is easily pushed out this way, helping get rid of it quickly.
Tubular Reabsorption: Some drugs can go back into the blood. For instance, drugs that dissolve well in fats can sometimes be reabsorbed, which can make them stay in the body longer.
Some drugs leave the body through bile. Bile goes into the intestines and eventually ends up in poop. This method is especially important for larger compounds. Sometimes, a drug can be reabsorbed from the intestines back into the body, which can keep it working longer.
Gases, like anesthesia or other substances that can evaporate, are mostly removed through the lungs. How fast this happens can depend on how well blood flows in the lungs and how much of the gas is in the blood compared to what’s in the air we breathe out.
Knowing how these excretion methods work is important for doctors when they prescribe medicine.
Renal Function: If a person has poor kidney function, like in chronic kidney disease, doctors need to change the dose of some medicines to avoid making the person sick. For instance, digoxin needs extra care in these cases because it has a small safe range.
Drug Interactions: Certain drugs can block the helpers that move other medicines out of the body. For example, probenecid can slow down how fast penicillin is removed, making penicillin work longer.
By understanding how these processes work, doctors can give patients the right doses and reduce side effects, keeping them safe while they take medicines.
Drug excretion is an important part of how our bodies handle medicine. After a medicine does its job, it needs to be removed from the body. There are three main ways this happens: through the kidneys, bile, and lungs.
The kidneys play a big role in getting rid of drugs. This happens in three main steps:
Glomerular Filtration: This is where drugs get filtered out of the blood in a part of the kidney called the glomerulus. Only drugs that aren’t attached to proteins can be filtered out.
Tubular Secretion: In this step, which happens in a part of the kidney called the proximal tubule, some drugs are actively pushed into the urine. Special helpers called transporters help with this. For example, penicillin is easily pushed out this way, helping get rid of it quickly.
Tubular Reabsorption: Some drugs can go back into the blood. For instance, drugs that dissolve well in fats can sometimes be reabsorbed, which can make them stay in the body longer.
Some drugs leave the body through bile. Bile goes into the intestines and eventually ends up in poop. This method is especially important for larger compounds. Sometimes, a drug can be reabsorbed from the intestines back into the body, which can keep it working longer.
Gases, like anesthesia or other substances that can evaporate, are mostly removed through the lungs. How fast this happens can depend on how well blood flows in the lungs and how much of the gas is in the blood compared to what’s in the air we breathe out.
Knowing how these excretion methods work is important for doctors when they prescribe medicine.
Renal Function: If a person has poor kidney function, like in chronic kidney disease, doctors need to change the dose of some medicines to avoid making the person sick. For instance, digoxin needs extra care in these cases because it has a small safe range.
Drug Interactions: Certain drugs can block the helpers that move other medicines out of the body. For example, probenecid can slow down how fast penicillin is removed, making penicillin work longer.
By understanding how these processes work, doctors can give patients the right doses and reduce side effects, keeping them safe while they take medicines.