[Lack of consensus on drug interactions: a descriptive analysis of information on interactions in the Laegemiddelkatalog, Medicinfortegnelse and product descriptions].
BACKGROUND
Practitioners' experience with inconsistencies between two Danish handbooks and the SPCs have lead to this comparative analysis of information on drug interactions in these publications. On the same background, a Danish database with drug interactions based on evidence and transparency is established.


METHODS
The material comprises information on 62 randomly selected drugs marketed in Denmark and described in the Laegemiddelkatalog, Medicinfortegnelse and 62 SPCs. A total of 586 drug interactions was analysed. This is a comparative analysis of the discrepancies of the information, the exactness of the name of the interacting drug, and applicability for health care personnel.


RESULTS
The comparison of the three sources shows inconsistency for 78% of the interactions. Fifty-nine percent of the interactions are mentioned in one source only. The distribution among the categories in the exactness of the name of the interacting drug (p=0.02), and applicability for health care personnel (p=0.0001) is not uniform for the three sources. The SPCs are less exact in mentioning the interacting drug and more often recommend actions to be taken to ameliorate drug interactions.


CONCLUSIONS
The consistency among the sources is relatively low. The inconsistency may contribute to patients' exposure to potentially severe drug interactions, first and foremost because of the omission of potentially severe drug interactions in the sources. It may also contribute to confusion on the part of health care personnel and drug users, which once again may lead to inadequate drug utilisation. There is a need for information on drug interactions and a consensus nationally in Denmark and probably internationally as well.
Petersen
Majken Nørskov
MN
Amager Hospital, H:S Apoteket, H:S Bispebjerg Hospital, Klinisk Farmakologisk Enhed, og Laegemiddelstyrelsen. majken.n.petersen@ah.hosp.dk
Christensen
Hanne Rolighed
HR
Kristensen
Mogens Brandt
MB
D002380:Catalogs, Drug as Topic; D032921:Consensus; D016208:Databases, Factual / Q000592:standards; D003718:Denmark; D004346:Drug Information Services / Q000592:standards; D004347:Drug Interactions; D004348:Drug Labeling / Q000592:standards; D006801:Humans; D017410:Practice Guidelines as Topic / Q000592:standards