A different view
It is good that pharmacists like Sue Howshall are on the alert for interactions while doing medicines use reviews (PJ, 2 September, p276). However, we take a slightly different view on some of the interactions she mentions.
Although the manufacturers of omeprazole recommend that patients taking warfarin should have their international normalised ratio measured if they are given warfarin, the evidence we have found suggests that any interaction is rare. Also, although some monitoring may be appropriate with large doses of fish oils, we have yet to see any evidence to suggest that concurrent use needs to be avoided.1 Mrs Howshall also makes the comment that one litre of ice cream can interact with warfarin, but so far there are only two cases on record, so its general importance is almost certainly small.1
Maybe we misunderstood the reasons behind these comments and recommendations but perhaps this patient has been denied some of these medicines which are probably safe, provided regular tests to ascertain the INR are being carried out, as well as any necessary dosage adjustments made.
We believe that we should take the opportunity to emphasise the fact that rare case reports do not, in isolation, confirm an interaction and patients should not be denied potentially beneficial treatment because of these rare occurrences.
Stockley’s Drug Interactions
1.Baxter K, editor. Stockley’s Drug Interactions, 7th ed. London: Pharmaceutical Press; 2005, pp281–2, p307.
Citation: Tomorrow's Pharmacist URI: 10002174
Recommended from Pharmaceutical Press
Remington Education: Physical Pharmacy provides a simple, concise view of the concepts and applications of physical pharmacy.£38.00