Abstract
Introduction
Converting oral Parksinon’s disease (PD) medications to transdermal Rotigotine is sometimes required when patients have swallowing difficulties. Correct dosing is important to avoid under-treatment and deterioration of PD symptoms. Conversely, excessive dopamine agonist can cause hallucinations and confusion. In the UK, 2 main dose conversion calculators exist: PD Med Calc1 and OPTIMAL2, both utilising different formulae. We compared both to identify any dose discrepancies in their recommendations, and select one for use within revised trust guidelines.
Methods
We conducted a retrospective analysis of 22 cases from pharmacy data of 1400 prescriptions issued between January 2021 - July 2022 for patients switched from oral PD medications to a Rotigotine Patch whilst admitted to a UK teaching hospital. We calculated the recommended Rotigotine patch dose from each patient’s usual oral medication regimen using both the PD Med Calc1 and OPTIMAL2 calculators to identify discrepancies.
Results
In 86% of cases (19/22) there was a difference between doses suggested by both calculators. Of these, 95% (18/19) showed OPTIMAL recommended doses 20-200% higher than PD Med Calc. In 5% (1/19) OPTIMAL recommended a marginally lower dose than PD Med Calc.
Conclusions
In dopamine agonist naive patients, PD Med Calc recommended a lower starting Rotigotine dose than OPTIMAL. Most admitted PD patients on patch conversion were older adults, and this population is particularly vulnerable to the side effects of excessive dopamine agonist exposure. The authors recommended using PD Med Calc within revised trust guidelines to minimise negative sequelae and ensure dosing consistency. 1 PD 'Nil by Mouth' Medication Dose Calculator http://pdmedcalc.co.uk/ 2 OPTIMAL Calculator - A Guideline for the OPTIMAL management of inpatients with Parkinson's Disease. http://www.parkinsonscalculator.com/index.html