A proposal to prevent omissions and delays of antiparkinsonian drug administration in hospitals.

Abstract

A prospective study carried out in the Netherlands showed that the most important risk factor for motor function deterioration in Parkinson's disease (PD) during hospital admission was medication error, including both incorrect timing of levodopa administration and prescription of contraindicated antidopaminergic drugs.1 Indeed, one of the reported reasons for omitting or delaying levodopa administration has been medication unavailability on time where needed, that is, in medical wards where the patient is admitted. Skelly et al in a recent study carried out in Derby Hospital (National Parkinson Foundation Centre of Excellence for Parkinson’s Disease) report that even in a ward specially designed to treat patients with PD, with an enhanced stock of anti-PD medications, 2.5% of all doses were not administered because the drug was not available on time.2 It is likely this problem is compounded in other nonspecialized wards and especially in smaller hospitals. To counteract this problem, Parkinson's United Kingdom “Get it on time campaign,”3 among others, has suggested that all commercially available antiparkinsonian drugs should be available in all hospital wards and on time. Given the data described previously, this seems unfeasible, especially in small hospitals where having available all the anti-PD drugs would certainly result in the expiration of many of these drugs before they are used. We think a possible solution can be found in Skelly et al’s reflections: “The available stock was not used as flexibly as we had hoped: e.g. doses of modified release medications were omitted rather than a temporary switch to available standard release drugs.”2 (p. 1246) We agree and propose a therapeutic interchange protocol (Figure 1) where the unavailable PD drug is first converted to the equivalent levodopa dose according to published dose equivalency.4 Then an immediate release levodopa dose could be administered until the original drug is available. Immediate release levodopa is cheap. Thus, having it in each hospital ward is a realistic approach. Figure 1. An example of applying the proposed protocol to prevent Parkinson’s disease (PD) drug omissions. It has to be kept in mind that dose equivalencies proposed by Tomlinson et al were developed to compare dose intensities of antiparkinsonian drugs in clinical trials rather than to use them in clinical practice and were catalogued by the authors as mere approximations. Paraphrasing Magdalinou et al5: “PD medications should be regarded as important as insulin is for diabetics.” (p. 540) Using short-acting insulin instead of the patient’s chronic insulin treatment is now routine clinical practice in hospitals. Although there may be some limitations to this approach, we think changing to an equivalent dose of immediate release levodopa could help to prevent PD drug omissions and delays.