What factors can influence drug metabolism in the body?

Drug metabolism is a complex process influenced by various physiological and genetic factors. All of the mentioned factors—age, weight, and genetic factors—play significant roles in how the body processes medications.

Age is particularly important because metabolic processes can vary significantly across the lifespan. For instance, infants may metabolize drugs differently than adults due to underdeveloped liver enzymes, while elderly individuals may experience slowed metabolism due to decreased organ function.

Weight can affect drug metabolism in terms of drug distribution in the body. Higher body weight can lead to an increased volume of distribution for certain medications, which may necessitate dosage adjustments to achieve the desired therapeutic effect.

Genetic factors, including polymorphisms in drug-metabolizing enzymes, can lead to variations in how individuals metabolize drugs. These genetic differences can affect the efficacy and safety of medications, resulting in variations that can make some patients fast or slow metabolizers.

Considering all these aspects, it is clear that drug metabolism is not determined by a single factor but rather a combination of age, weight, and genetics, making "all of the above" the correct answer. This understanding is crucial for ensuring optimal medication management and patient care within pharmacy practice.