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.