Which of the following is an example of pharmacokinetic interaction?

Pharmacokinetic interactions refer to how the body affects a drug's absorption, distribution, metabolism, and excretion. Option C is correct because it specifically addresses how liver impairment can reduce the metabolism of a drug. The liver plays a crucial role in metabolizing many medications, and when its function is compromised, it can lead to higher concentrations of the drug in the bloodstream, potentially enhancing its effects or increasing the risk of toxicity.

This concept illustrates a key pharmacokinetic principle: that alterations in the body's ability to process a drug can change its therapeutic levels or side effects. Thus, understanding how liver health affects drug metabolism is essential for safe and effective medication management. In contrast, the other options predominantly illustrate pharmacodynamic interactions, which concern how the effects of drugs are altered due to various factors.