Drug absorption from the gastrointestinal tract (GIT)

puvvukonvict September 19, 2024

Drug absorption from the gastrointestinal tract (GIT) can be significantly influenced by both the age and the disease state of a subject. Here's how

Photo by julien Tromeur on Unsplash

Age

1. Infants and Children:

Gastric pH: Infants have higher gastric pH (less acidic) which can affect the solubility of some drugs. Over time, gastric pH decreases to more adult levels.

Gastric Emptying and Motility: Infants and young children often have slower gastric emptying and variable gastrointestinal motility, which can alter drug absorption rates.

Surface Area and Enzyme Activity: The surface area and enzyme activity in the intestines may differ from adults, influencing drug absorption.

2. Elderly:

Gastric pH: Elderly individuals often have higher gastric pH due to decreased gastric acid secretion, which can impact drug solubility and absorption.

Gastric Emptying and Motility: Gastric emptying and intestinal motility can slow with age, affecting how quickly and effectively drugs are absorbed.

Blood Flow: Reduced blood flow to the gastrointestinal tract can affect the absorption of drugs.

Enzyme Activity and Liver Function: Decreased liver function and enzyme activity can impact drug metabolism and clearance.

Disease State

1. Gastrointestinal Disorders:

Inflammatory Bowel Disease (IBD): Conditions like Crohn’s disease and ulcerative colitis can alter drug absorption due to inflammation and changes in bowel function.

Celiac Disease: Damage to the intestinal lining in celiac disease can reduce the surface area available for absorption.

Peptic Ulcer Disease: Ulcers can affect gastric pH and motility, influencing drug absorption.

2. Liver Disease:

Liver diseases like cirrhosis can affect drug metabolism and clearance, impacting the effective concentration of drugs in the system.

3. Renal Disease:

Impaired kidney function can affect drug excretion and overall pharmacokinetics, which might necessitate adjustments in dosage or frequency.

4. Metabolic Conditions:

Conditions like diabetes can affect gastrointestinal motility and blood flow, which can in turn impact drug absorption.

Overall, the physiological and pathological changes associated with age and disease states can lead to variations in drug absorption, necessitating careful consideration in drug dosing and management.