Clinically Relevant Drug-Drug and Drug-Food Interactions: Underlying Mechanisms and Regulatory Requirements for Drug Licensing

Knowledge, attitude and practice (KAP) on food-drug interaction (FDI) among pharmacists working in government health facilities in Sabah, Malaysia

BACKGROUND

Food-drug interaction (FDI) is prevalent in our day-to-day life. Widely recognised as drug expert, pharmacists are responsible to provide patient education, including on FDI, to ensure optimum safety and efficacy of treatment. Most pharmacists have knowledge and experience regarding FDI to certain extent. However, the level of knowledge, attitude and practice (KAP) towards FDI among pharmacists were yet to elucidated for many countries, including for Malaysia.

OBJECTIVE

This study aims to assess pharmacists' KAP on FDI, their inter-association, as well as association with sociodemographic characteristics in Sabah, Malaysia.

METHODS & MATERIALS

A cross-sectional study was conducted from 1 to 31 May 2023, using online, self-administered Google Form questionnaire, involving 24 government hospitals and 113 government health clinics in Sabah.

RESULTS

A total of 273 (or 35.5%) out of 768 pharmacists responded. Over two-third were female and serving government hospitals (79.6%). Mean score of KAP were 72.5 ± 14.3%, 93.2 ± 8.3% and 56.0 ± 16.7%, respectively, reflected good attitude but moderate knowledge and practice. Knowledge gaps identified include common medications such as paracetamol and metformin.Additionally, 28.2% respondents reported lack of FDI coverage during undergraduate, while merely 17.2% have received formal training on FDI after started working. Although 89.0% respondents agree that informing patients about possible FDIs is their responsibility, only 35.9% of the respondents usually or always practiced this. Such discrepancy maybe attributed to insufficient pharmacists' knowledge on FDI, where pharmacists with good level of knowledge have almost 2 times higher odd for good level of practice, compared to those with poor/moderate knowledge (odds ratio, OR: 1.92; 95% CI 1.02-3.61; p = 0.040) in this study.

CONCLUSION

There are significant training gaps to be filled in. Pharmacist possessing good knowledge is a prerequisite for better pharmacy practice. Adequate education strategies covering FDI should be emphasised for all pharmacy undergraduates and practising pharmacists.

CYP1A2 mRNA Expression Rather than Genetic Variants Indicate Hepatic CYP1A2 Activity

CYP1A2, one of the most abundant hepatic cytochrome P450 enzymes, is involved in metabolism of several drugs and carcinogenic compounds. Data on the significance of CYP1A2 genetic polymorphisms in enzyme activity are highly inconsistent; therefore, the impact of CYP1A2 genetic variants (−3860G>A, −2467delT, −739T>G, −163C>A, 2159G>A) on mRNA expression and phenacetin O-dealkylation selective for CYP1A2 was investigated in human liver tissues and in psychiatric patients belonging to Caucasian populations. CYP1A2*1F, considered to be associated with high CYP1A2 inducibility, is generally identified by the presence of −163C>A polymorphism; however, we demonstrated that −163C>A existed in several haplotypes (CYP1A2*1F, CYP1A2*1L, CYP1A2*1M, CYP1A2*1V, CYP1A2*1W), and consequently, CYP1A2*1F was a much rarer allelic variant (0.4%) than reported in Caucasian populations. Of note, −163C>A polymorphism was found to result in an increase of neither mRNA nor the activity of CYP1A2. Moreover, hepatic CYP1A2 activity was associated with hepatic or leukocyte mRNA expression rather than genetic polymorphisms of CYP1A2. Consideration of non-genetic phenoconverting factors (co-medication with CYP1A2-specific inhibitors/inducers, tobacco smoking and non-specific factors, including amoxicillin+clavulanic acid therapy or chronic alcohol consumption) did not much improve genotype−phenotype estimation. In conclusion, CYP1A2-genotyping is inappropriate for the prediction of CYP1A2 function; however, CYP1A2 mRNA expression in leukocytes can inform about patients’ CYP1A2-metabolizing capacity.

Metabolism of a New Antiaggregant, Indolinone Derivative

Cytochrome p450-mediated metabolism of GRS (indolinone antiaggregant) and its effects on activities of cytochrome p450 isoenzymes were studied. Inhibition of 6 isomers of cytochrome p450 in human liver microsomes was studied with the use of specific substrates. It was found that human liver cytochrome p450 enzymes could not induce degradation of GRS and that GRS was not an inductor or inhibitor of cytochrome p450 family members 1A2, 2C9, 2C19, 2D6, 2C8, and 3A4. Hence, clinical use of the prospective antiaggregant would not involve the risk of uncontrolled fluctuations in GRS concentrations in the organism because of interactions between the drugs.