Physiological factors that can influence drug metabolism include
age
, individual variation (e.g., pharmacogenetics), enterohepatic circulation, nutrition, intestinal flora, or sex differences. In general, drugs are metabolized more slowly in fetal, neonatal and elderly humans and animals than in adults.
What factors may influence drug metabolism or excretion in this patient?
- Physiological Conditions (age, diet, hormone balance)
- Pathological Conditions (impaired liver or kidney function)
- Genetic Factors (species/strain difference, sex, ethnic polymorphism, individual differences)
- Drug-drug Interactions (enzyme inhibition, enzyme induction)
What factors affect drug metabolism in elderly?
Aging results in a number of significant changes in the human liver including reductions in liver blood flow, size,
drug-metabolizing enzyme content
, and pseudocapillarization. Drug metabolism is also influenced by comorbid disease, frailty, concomitant medicines, and (epi)genetics.
What are the factors affecting drugs?
- Type of drug.
- Quantity of drug used.
- Method of drug use.
- Time taken to consume.
- Tolerance.
- Gender, size and amount of muscle.
- Use of other psycho-active drugs.
- Mood or attitude.
What are 2 general factors that can influence drug metabolism?
Various physiological and pathological factors can also affect drug metabolism. Physiological factors that can influence drug metabolism include age, individual variation (e.g., pharmacogenetics),
enterohepatic circulation, nutrition, intestinal flora, or sex differences
.
What organ systems are involved in excretion of drugs?
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 four routes are drugs excreted?
- Urine,
- Tears,
- Perspiration.
- Saliva.
- Respiration.
- Milk.
- Faeces.
- Bile.
How are drugs distributed?
Drug distribution is
the disbursement of an unmetabolized drug as it moves through the body’s blood and tissues
. The efficacy or toxicity of a drug depends on the distribution in specific tissues and in part explains the lack of correlation between plasma levels and the effects that are seen.
Why are elderly more sensitive to drugs?
Increased Sensitivity to Many Drugs: The
problems of decreased body size
, altered body composition (more fat, less water), and decreased liver and kidney function cause many drugs to accumulate in older people’s bodies at dangerously higher levels and for longer times than in younger people.
How does disease affect drug response?
The absorption, distribution, metabolism, and elimination (ADME) of drugs can be influenced by
the physiological and biochemical changes
that occur due to various diseases. These changes can have dramatic influence on the exposure of drugs and lead to drug toxicity or lack of drug efficacy.
How does weight affect drug effectiveness?
Changes in body weight
can influence the amount of medicine you need to take and how long it stays in your body
. The circulatory system may slow down, which can affect how fast drugs get to the liver and kidneys.
What are 4 factors that affect absorption of a drug?
- Lipid water solubility. Lipid water solubility coefficient is the ratio of dissolution of drug in lipid as compared to water. …
- Molecular size. …
- Particle size. …
- Degree of Ionization. …
- Physical Forms. …
- Chemical Nature. …
- Dosage Forms. …
- Formulation.
How does genetic factors affect drug metabolism?
Genetic polymorphisms have been identified for many drug-metabolizing enzymes, including the cytochrome P450 (CYP450) enzymes. This gives rise to
distinct population
phenotypes of persons who have metabolism capabilities ranging from extremely poor to extremely fast.
What are the phases of drug metabolism?
Drugs can be metabolized by
oxidation, reduction, hydrolysis, hydration, conjugation, condensation, or isomerization
; whatever the process, the goal is to make the drug easier to excrete. The enzymes involved in metabolism are present in many tissues but generally are more concentrated in the liver.
How do drugs exit the body?
The last phase of a drug within the body is
excretion
. This is the process by which drugs and their metabolites exit the body, primarily via urine or feces. Drugs may also be excreted in sweat, saliva, breast milk, or exhaled air. A substance may be excreted in its altered, or metabolized, form or excreted intact.
Where are drugs metabolized?
Most drugs must pass through
the liver
, which is the primary site for drug metabolism. Once in the liver, enzymes convert prodrugs to active metabolites or convert active drugs to inactive forms. The liver’s primary mechanism for metabolizing drugs is via a specific group of cytochrome P-450 enzymes.
