Discussion
Drug-drug interactions causing adverse drug reactions remain a significant, avoidable health risk to patients. The impact of drug-drug interactions can range from mild to fatal.12 It has been reported most actual drug-drug interactions causing adverse drug reactions occur in a secondary care setting, resulting in a prolonged hospital stay.5 This therefore emphasises the importance of drug-drug interactions recognition in health education.
This review revealed of the total drug-drug interactions identified, the majority of interactions were either moderate or severe severity (64%) – where 29% (16/54) were severe severity and 35% (19/54) were moderate severity. This appears to be consistent with world-wide studies conducted on drug-drug interactions.13,14
On review of the mechanisms of the drug-drug interactions, 87% (47/54) were pharmacokinetic driven reactions compared to 13% (7/54) pharmacodynamic driven reactions. These figures are consistent with already published literature, which found drug-drug interactions mainly driven by pharmacokinetic type reactions.15
Cardiovascular medications that are frequently involved in severe drug-drug interactions include anti-arrhythmics 16, anti-platelets 17,18, and anti-coagulants17,19. Our review remains consistent with this, as the medications responsible for ‘severe’ drug-drug interactions with serious adverse effects included: anti-arrhythmics, digoxin, ticagrelor, nicorandil, ranolazine and warfarin; therefore, for patients already established on these respective medications, great care is recommended when prescribing CF exacerbation medications in order to reduce drug-related morbidity and mortality.
However, a limitation of this review is that not all the drug-drug interaction severities were known, and some drug-drug interactions still had no management recommendations. Second, potential drug-drug interactions that may arise given a certain drug combination was the main focus, not incidences of actual drug-drug interactions. An additional limitation of this review could be using one source of drug interaction checking methods.
Therefore, future research is required to validate the clinical consequences of these respective potential drug-drug interactions. It would also be interesting to see whether incidence rates of drug-drug interactions are consistent with similar world-wide studies already conducted into cardiovascular drug-drug interactions.