Drug-drug, drug-herb, and drug-food interactions among cancer patients

During their cancer treatment path, cancer patients use numerous drugs,e.g.:

• anticancer medications,
• supportive drugs,
• other prescribed medications,
• herbal remedies,
• other OTC products.

This puts them at risk of significant drug interactions (DIs).

This study describes potential DIs in cancer patients and their prevalence and predictors.

A cross-sectional study was carried out in two centers in the northern West Bank, Palestine. The Lexicomp® Drug Interactions tool (Lexi-Comp, Hudson OH, USA) was applied to check the potential DIs. In addition, the Statistical Package for the Social Sciences (SPSS) was used to show the results and find the associations.

The final analysis included 327 patients. Most of the participants were older than 50 years (61.2%), female (68.5%), and had a solid tumor (74.6%). The total number of potential DIs was 1753, including 1510 drug-drug interactions (DDIs), 24 drug-herb interactions, and 219 drug-food interactions. Importantly, the prevalence of DDIs was 88.1%. In multivariate analysis, the number of potential DDIs significantly decreased with the duration of treatment (p = 0.007), while it increased with the number of comorbidities (p < 0.001) and the number of drugs used (p < 0.001).

The authors concluded that they found a high prevalence of DIs among cancer patients. This required health care providers to develop a comprehensive protocol to monitor and evaluate DIs by improving doctor-pharmacist communication and supporting the role of clinical pharmacists.

What the investigators did not study was the possibility of herb-herb and herb-non-herbal supplement interactions. The reason for this is probably simple: we know too little about these areas to make reasonable judgments. But even in the absence of such considerations, the prevalence of DDIs among cancer patients was high (88.1%). This means that the vast majority of cancer patients had at least one potential DDI. Over half of them were classified as moderately severe or worse.

The lessons seem to be to:

• use only truly necessary drugs and omit all remedies that are of doubtful value,
• educate the public about the risks of interactions,
• be skeptical about the messages of integrative medicine,
• consult a healthcare professional who is competent to make such judgments,
• conduct more rigorous research to increase our knowledge in this complex area.