The greatest proportion of drug excretion occurs through
the kidneys
. The liver makes most drugs and remedies water soluble for removal via the kidneys (see Figure 17.1, p. 131). One-fifth of the plasma reaching the kidney glomerulus is filtered through the pores in the glomerular cell membrane.
What are the 4 main ways a drug is excreted?
Drug excretion is the removal of drugs from the body, either as a metabolite or unchanged drug. There are many different routes of excretion, including
urine, bile, sweat, saliva, tears, milk, and stool
.
How are most drugs eliminated from the body?
Most drugs, particularly water-soluble drugs and their metabolites, are eliminated largely by
the kidneys in urine
. Therefore, drug dosing depends largely on kidney function. Some drugs are eliminated by excretion in the bile (a greenish yellow fluid secreted by the liver and stored in the gallbladder).
What is the main site of drug excretion?
Although many sites of metabolism and excretion exist, the chief organ of metabolism is the liver, while the organ primarily tasked with excretion is
the kidney
. Any significant dysfunction in either organ can result in the accumulation of the drug or its metabolites in toxic concentrations.
What are the most common routes by which medications are eliminated from the body quizlet?
- The kidneys. -Most drugs leave the body in the urine, either unchanged or as polar metabolites.
- The hepatobiliary system. …
- The lungs. …
- Excreted with milk or sweat (minor amounts)
What happens if a drug is not metabolized?
If your body metabolizes a drug too slowly,
it stays active longer
, and may be associated with side effects. Because of this, your doctor may characterize you as being one of four metabolizer types, with respect to a specific enzyme. Poor metabolizers have significantly reduced or non-functional enzyme activity.
How do you excrete drugs quickly?
In the treatment of poisoning with some drugs, the acidity of the urine is changed by giving
antacids
(such as sodium bicarbonate) or acidic substances (such as ammonium chloride) orally to speed up the excretion of the drug.
What does half life mean for drugs?
The half-life of a drug is
the time it takes for the amount of a drug’s active substance in your body to reduce by half
. This depends on how the body processes and gets rid of the drug. It can vary from a few hours to a few days, or sometimes weeks.
Which is the major process of absorption for more than 90% of drugs?
Passive diffusion or non-ionic diffusion
is considered as the major absorption process for more than 90% of drugs (see figure 3). It is the movement of the drug molecule from a region of higher concentration to a region of lower concentration.
What is excreted faster in basic urine?
Most drugs are either weak acids or weak bases. In alkaline urine,
acidic drugs
are more readily ionised. In acidic urine, alkaline drugs are more readily ionised. Ionised substances (also refered to as polar) are more soluble in water so dissolve in the body fluids more readily for excretion.
What is the difference between elimination and excretion of a drug?
Elimination is the removal of unwanted materials out of the body. Specifically, it refers to the removal of undigested materials, occurring through feces, out of the body. Meanwhile, excretion is a method of elimination that removes the nitrogenous
wastes
out of the body through urine.
How drugs are processed in the body?
Drugs undergo four stages within the body:
absorption, distribution, metabolism, and excretion
. After a drug is administered, it is absorbed into the bloodstream. The circulatory system then distributes the drug throughout the body. Then it is metabolized by the body.
What is the difference between elimination and excretion?
Excretion involves only in the removal of metabolic waste from the body, whereas
elimination is involved in removal of waste and indigestible food material from the body
.
What does a bioavailability of 1 mean?
Bioavailability is (1)
the fraction of an administered dose of a drug that reaches the systemic circulation as intact drug (expressed as F) and (2) the rate at which this occurs
. As an i.v. dose is injected directly into the systemic circulation, the bioavailability of an i.v. dose is by definition 100 percent (F=1).
Which of the following can affect drug distribution inside the body?
Drug distribution is affected by many factors, including
plasma or tissue protein binding, body weight, body composition, and body fluid spaces
(8). Of these, total body weight, muscle mass, and fat composition are the major determinants of drug distribution, and women may differ from men in both of these factors.
Which of the following is the main site of drug elimination quizlet?
The kidneys
are the primary organ system responsible for drug elimination. To a lesser extent, the GI tract, the respiratory system, sweat, saliva, tears, and breast milk are also involved. Which of the four phases of pharmacokinetics is concerned with solubility?
