What can developing tolerance to a medication indicate?

Developing tolerance to a medication indicates that over time, the same dose of the drug leads to a diminished effect. This usually happens because the body adapts to the presence of the drug, which may involve physiological changes that reduce its effectiveness. For instance, with chronic use of certain medications, the body may increase the activity of enzymes that metabolize the drug, leading to a need for higher doses to achieve the same therapeutic effect. This is particularly common with medications that affect neurotransmitter systems, such as opioids or certain antidepressants.

In contrast to the other options, where increased side effects might occur or dosage requirements might need to be adjusted, the primary hallmark of tolerance is that the original dose no longer produces the desired effect. This scenario can lead healthcare providers to reconsider the treatment plan to ensure that the patient continues to receive effective therapy.