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.
What is drug metabolism in medicinal chemistry?
Drug metabolism is the chemical alteration of a drug via a biological system to aid its elimination by increasing its hydrophilicity. … Since drug metabolism is mediated by enzymes, there is potential for natural variability and for co-administered drugs to interact, either by enzyme inhibition or induction.
What is the main purpose 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.
What are the pathways of drug metabolism?
The routes by which drugs may be metabolised or biotransformed are many and varied and include the chemical reactions of oxidation, reduction, hydrolysis, hydration, conjugation and condensation.
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.
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 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 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 is oxidation in drug metabolism?
In most cases, an oxygen atom is retained in the metabolite, although some reactions, such as dealkylation, result in loss of the oxygen atom in a small fragment of the original molecule. Oxidation reactions are catalysed by a diverse group of enzymes, of which the cytochrome P450 system is the most important.
What organs are involved in drug metabolism?
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.
What causes slow drug metabolism?
Underlying health conditions can also influence your drug metabolic rate. Some concerning ones are chronic liver disorders, kidney dysfunction, or advanced heart failure. Drug and Food Interactions. CYP450 enzymes can be impacted by the foods you eat and other drugs you take.
What are the importance and consequences of drug metabolism?
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.
What is meant by drug metabolism?
Drug metabolism is the metabolic breakdown of drugs by living organisms, usually through specialized enzymatic systems.
What are the factors affecting metabolism?
Your metabolic rate is influenced by many factors – including age, gender, muscle-to-fat ratio, amount of physical activity and hormone function.
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.