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 drugs are metabolized in the body?
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.
What are the four stages of drug metabolization?
The method by which a drug is administered, along with other factors, determines the speed of onset of effects. Drugs undergo four stages within the body: absorption, distribution, metabolism, and excretion.
Why are most drugs metabolised and not excreted?
The majority of metabolic processes that involve drugs occur in the liver, as the enzymes that facilitate the reactions are concentrated there. The purpose of metabolism in the body is usually to change the chemical structure of the substance, to increase the ease with which it can be excreted from the body.
Why do I metabolize drugs so quickly?
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.
What factors affect metabolism of a drug?
Many factors affect the rate and pathway of metabolism of drugs, and the major influences can be sub-divided into internal (physiological and pathological) and external (exogenous) factors as indicated below: Internal: species, genetic (strain), sex, age, hormones, pregnancy, disease. External: diet, environment.
What organ is alcohol metabolized in?
Although the liver is the main organ responsible for metabolizing ingested alcohol, stomach (i.e., gastric) ADH has been reported to contribute to FPM.
What are the 5 ways drugs can enter your body?
For example, there are five methods of drug abuse which allow drugs to enter the body: swallowing, smoking, snorting, through suppositories and injecting.
What is half life of a drug?
The half-life of a drug is the time it takes for the amount of it in your body to be reduced by half. This depends on how the body processes and gets rid of the drug, and can vary from a few hours to a few days.
What is first pass metabolism of drug?
The drug is absorbed from the GI tract and passes via the portal vein into the liver where some drugs are metabolised. Sometimes the result of first pass metabolism means that only a proportion of the drug reaches the circulation. First pass metabolism can occur in the gut and the liver.
What kind of drugs can be excreted by the kidneys?
Most drugs (or metabolites) are excreted by the kidneys. Three process can occur in renal excretion: glomerular filtration, tubular secretion and passive reabsorption. Some drugs are eliminated by the liver in the bile and excreted in feces.
What factors can affect drug metabolism in an 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.
Which drug is not metabolized by acetylation?
Procainamide (antiarrhythmic) Sulfa drugs (e.g. sulfonamide antibiotics) Dapsone (anti-leprosy, antiparasitic)
What does increased metabolism of a drug mean?
When they increase the enzyme’s metabolic function, the drug’s therapeutic effects may be decreased. When they decrease the enzyme’s metabolic function, the drug’s benefits may be compromised by intolerability. Your metabolic enzyme systems change throughout your lifetime.
What causes drug intolerance?
Two effects most often cause drug intolerance: changes in the gut microbiome and the potential cross-reactivity of the antibiotic itself with other organs, typically the nervous system.
What does it mean to be a poor metabolizer of a drug?
Poor metabolizer: Patients who are poor metabolizers experience a very slow breakdown of medications, making side effects more pronounced. That means standard doses of certain medications may not work as intended. … Patients are likely to metabolize medication normally and medication is likely to work as intended.