Because of their genetic makeup, some people process (metabolize) drugs slowly. As a result, a drug may accumulate in the body, causing toxicity. Other people metabolize drugs so quickly that after they take a usual dose, drug levels in the blood never become high enough for the drug to be effective.
How do genetics affect drugs?
Part of that variability is due to genetics. Genes
influence the numbers and types of receptors in peoples' brains
, how quickly their bodies metabolize drugs, and how well they respond to different medications.
How does genetic factors affect drug metabolism?
Genetic polymorphisms have been identified for many drug-metabolising 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
.
Why is genetics important in pharmacy?
We are at a pivotal moment in medical science and pharmacy practice where specific variations in the genetic code are being associated with
differences in drug response
, an individual's propensity for developing certain drug side effects, and variation in the rate and extent of drug metabolism.
What factors affect metabolism of a drug?
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 causes slow drug metabolism?
Underlying health conditions can also influence your drug metabolic rate. Some conditions at greater risk of this are
chronic liver disorders
, kidney dysfunction, or advanced heart failure.
What are the benefits of pharmacogenomics?
- More powerful medicines. …
- Better, safer drugs the first time. …
- More accurate methods of determining appropriate drug dosages. …
- Advanced screening for disease. …
- Better vaccines. …
- Improvements in the drug discovery and approval process. …
- Decrease in the overall cost of health care.
What drugs are affected by genetics?
- Fluorouracil (Adrucil®) Fluorouracil (5-FU) is one of the most successful and widely used chemotherapy drugs. …
- Clopidogrel (Plavix®) …
- Tamoxifen (Nolvadex®) …
- Atomoxetine (Strattera®) …
- Warfarin (Coumadin®)
What is an example of pharmacogenomics?
Here are some examples of pharmacogenomic testing in cancer care:
Colorectal cancer
. Irinotecan (Camptosar) is a type of chemotherapy. Doctors commonly use it to treat colon cancer.
What are the four stages of drug metabolization?
Think of pharmacokinetics as a drug's journey through the body, during which it passes through four different phases:
absorption, distribution, metabolism, and excretion (ADME)
.
What factors can affect drug metabolism in the 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.
Does gender affect drug absorption?
Total drug absorption does not appear to be significantly affected by sex
although absorption rates may be slightly slower in women. Bioavailability after oral drug dosing, for CYP3A substrates in particular, may be somewhat higher in women compared to men.
How do drugs exit the body?
While drugs and their metabolites are mostly
excreted by the kidneys into urine
, drugs can also leave the body in other methods, such as breath and sweat, hence the noticeable smell of alcohol on someone who has been drinking very heavily.
How concentrated is the drug after 2 hours of administration?
1 hour after the drug administration, 6.25 mg of the drug remains in the body. 2 hours after the drug administration,
0.39 mg of
the drug remains in the body.
What are the phases of drug metabolism?
The metabolism of xenobiotics is often divided into three phases
:- modification, conjugation, and excretion
. These reactions act in concert to detoxify xenobiotics and remove them from cells.
What is the purpose and the goal of pharmacogenomics?
Pharmacogenomics (sometimes called pharmacogenetics) is a field of research that studies how a person's genes affect how he or she responds to medications. Its long-term goal is
to help doctors select the drugs and doses best suited for each person
.
