Introduction: Drug-disease interactions include the impact of a drug and a particular disease condition on each other. However, the current practice in addressing drug-disease interaction is unbalanced and mostly limited to how the drug worsens the disease or health condition.
Areas covered: Aspirin and gastric ulcer interaction are used as an example to illustrate this concept, especially the narration of how disease affects drug efficacy. The number of molecules that make up 100 mg of aspirin is identified with a view to discuss the pharmacokinetics, especially in terms of absorption and distribution. Using hypothetical scenarios, the pharmacodynamics in co-morbidities that could involve gastric ulcer and aspirin are also discussed.
Expert opinion: There seems to be oversight in definition and description of drug-disease interaction, which is often limited to ‘how drug exacerbates disease’. The implication of this limited definition is that the discussions, research and teaching of the topic either lacks information, or are not clear on ‘how disease affects drug efficacy’. For example, gastric ulcer has the potential to enhance absorption, bioavailability and therapeutic effects of aspirin, but this is rarely discussed in preference to the probability of gastro-intestinal bleeding side-effect.