PDMedCalc: 'nil by mouth' medication dose calculator

PDMedCalc has been endorsed by the authors of the Centre for Perioperative Care's Clinical Guideline for Perioperative Care of People with Parkinson' Disease. It's the only medication calculator endorsed in this guideline which is the first of its kind nationally and internationally.

Who is this tool for?

Doctors, nurses and pharmacists looking after patients with Parkinson's who have been admitted to hospital and are unable to take their medications orally.

What is the purpose of the tool?

• Suddenly stopping Parkinson's medications can be extremely dangerous and due to the risk of neuroleptic malignant syndrome, potentially even fatal.
• In patients unable to take their usual Parkinson's medications orally, this tool is designed to convert a patient's usual Parkinson's medications to a "Levodopa equivalent dose" (LED). The LED is then used to calculate the dose of dispersible Madopar to be given via a nasogastric tube to provide a patient with their usual amount of Parkinson's medication.
• The tool also provides a conversion to a rotigotine patch dose, as an alternative to nasogastric dispersible Madopar. A correction factor is applied to avoid large rotigotine patch doses, as these may cause side effects such as confusion, hallucinations or delirium.
• Amantadine can be safely omitted if swallow is compromised. If the patient is on a subcutaneous Apomorphine infusion, Duodopa (via PEJ) or a subcutaneous ProDuodopa infusion (foslevodopa/foscarbidopa) no conversion is required; please continue to use their existing non-oral treatment.

Where did this tool come from?

The development of the tool was led by James Fisher and the Northumbria Healthcare NHS Foundation Trust Parkinson's Disease team in 2014, who worked in collaboration with Daniel Jamieson (Computing Science PhD student at Newcastle University).

The tool was redeveloped in 2024 with support from TPXimpact and funding from an Excellence Network project grant.

PDMedCalc was registered with the UK Medicines and Healthcare products Regulatory Agency (MHRA) as a Class 1 medical device on 15 February, 2024.

If you have any questions about PDMedCalc, please contact [email protected].

Note for people with Parkinson's

This resource is intended for use by professionals only. People with Parkinson's are advised to consult with their specialists before making any changes to their medication.

Disclaimer

This tool is no substitute for clinical reasoning nor should it be used as a substitute for expert advice. Please ensure you liaise with your local Parkinson's and pharmacy teams about any patient with Parkinson's who is unable to take their usual medicines.

Extensive effort has been made to ensure this tool is as accurate as possible, however the accuracy and completeness of the information provided can't be guaranteed.

The tool should therefore be used as a guide, with no medical decision being solely made on the results provided by this tool.