Which groups of people are especially sensitive to medication effects?

Infants are especially sensitive to medication effects due to several physiological and developmental factors. At this stage of life, their metabolic processes and organ systems, including the liver and kidneys, are still maturing and may not function at the same efficiency as in older individuals. This can lead to altered drug absorption, distribution, metabolism, and excretion, making them more susceptible to both the therapeutic effects and potential side effects of medications.

Moreover, infants have a higher body water content and lower body fat compared to older children and adults, which can affect the pharmacokinetics of hydrophilic and lipophilic drugs. Additionally, their immune systems are still developing, which can influence how they respond to medications, particularly those that may elicit immune responses or vary in their efficacy during early stages of life.

The sensitivity of this age group is underscored by the need for careful dosing and monitoring when prescribing medications to infants, as inappropriate dosages can lead to severe adverse effects. Other groups, while they may also have varying sensitivities, do not exhibit the same level of vulnerability to medication effects as infants.