Question

Develop a table that addresses the phases of pharmacokinetics (absorption, distribution, metabolism, excretion) for the following developmental stages:

Children

Older Adults

Answer 1

Children

Absorption	distribution	metabolism	excretion
Absorption. The composition of intestinal fluids and the permeability of the gut vary during childhood. Absorption of orally administered drugs is affected by changes in gastric pH which decreases during infancy to reach adult values by two years of age.infants are high risk of skin toxicity via skin absorption because of larger surface area to volume ratio, they absorb more drug.	The volume of distribution of drugs changes in children with aging. These age-related changes are due to changes in body composition (especially the extracellular and total body water spaces) and plasma protein binding. Higher doses (per kg of body weight) of water-soluble drugs are required in younger children because a higher percentage of their body weight is wA	as children mature, liver enzymes are able to effectively metabolize most drugs, because the BMR in children is higher than in adults, drugs are metabolized more quickly. thus drug dosages relative to body weight may need to be higher for children than adults.	The renal excretion of unchanged drug is generally lower in newborns owing to the immaturity of renal function. However a similar or greater rate of renal excretion has been observed in infants and preschool children compared with adult values for some drugs.increased creatine clearance in children.

Adults

Absorption	metabolism	distribution		Elemination
Despite an age-related decrease in small-bowel surface area, slowed gastric emptying, and an increase in gastric pH, changes in drug absorption tend to be clinically inconsequential for most drugs.decrease in drug absorption occurs in older adults	Overall hepatic metabolism of many drugs through the cytochrome P-450 enzyme system decreases with age.decrease d hepatic blood flow and clearance cause decrease metabolism.	With age, body fat generally increases and total body water decreases. Increased fat increases the volume of distribution for highly lipophilic drugs (eg, diazepam, chlordiazepoxide) and may increase their elimination half-lives.decrease serum albumin level cause increase in concentration of drug cause drug toxicity		One of the most important pharmacokinetic changes associated with aging is decreased renal elimination of drugs. After age 40, creatinine clearance decreases an average of 8 mL/min/1.73 m2/decade; however, the age-related decrease varies substantially from person to person. Serum creatinine levels often remain within normal limits despite a decrease in GFR because older adults generally have less muscle mass and are generally less physically active than younger adults and thus produce less creatinine.decrease creatinine clearance cause decrease elemination of drug