P43 Ketogenic diets – how can pharmacy help?
Authors: Edrich Courtney 
Published: April 2023

Situation

Ketogenic dietary treatments are established, effective, non-pharmacologic treatments for drug resistant childhood epilepsy. They generally consist of a high fat and low carbohydrate diet. Medications, particularly in a liquid formulation, often contain potentially significant amounts of carbohydrate, and upon ingestion, can rapidly reverse ketosis leading to seizure activity.

Methods

Prior to initiation or during the early stages of the diet, the ketogenic diet team seek pharmacy advice on the appropriateness of individual patient’s medications with the overall aim to reduce carbohydrate content as much as possible. The assessment process consists of identifying current brands of medications and their indications, and further investigating quantities of ‘problem’ excipients either by reviewing the product information or liaising directly with the manufacturer. Liquid formulations of medications, even when marked sugar-free, often contain large quantities of other sweetening agents that can be sources of carbohydrate – although there are an increasing number of recently launched brands using sweetening agents with no calorific value, and thus are not a concern.

Tablets/capsules are often used as they contain minimal carbohydrate; however, manipulation is often required as a large quantity of our patients require administration of their medicines via an enteral feeding tube. There are many factors to consider when switching between formulations, of which the clinicians should be made aware, and this may influence choice of formulation/therapy. For example: Is the medication brand specific? Are the formulations bioequivalent? Will feed/food interactions differ between formulations? Exposure to new excipients. Change in licensing status. Are the doses achievable using the new formulation?

Similarly, use of a new formulation via an enteral feeding tube may pose more issues for consideration. For example, can the formulation be manipulated and administered successfully via the enteral feeding tube? Will manipulation change the pharmacokinetics of the drug? Will the absorption be affected? Relevant COSHH assessment/risks. The majority of information provided to the clinicians will be considered off-label or unlicensed, thus it is important to review literature carefully.

Outcome

Over the previous years, as the ketogenic diet patient cohort has expanded, pharmacy involvement and expertise has increased. We have been able to play a more prominent role in direct patient care, offering suitable advice and alternatives regarding medication. The vast number of enquiries received has enabled us to document and build a comprehensive internal database (at present we have information on >70 drugs), which can significantly reduce the time taken to investigate and provide advice for future patients. In 2021 alone we received 49 enquiries, involving at least 16 patients and we provided advice on over 50 different drugs.

Lessons Learned

Communication is key to help with decision making – clinicians and dieticians can often adapt medication doses/diet to allow for more appropriate or ketogenic diet friendly formulations. Product SmPC and the PIL are useful resources for identifying carbohydrate content, although not all excipient quantities are listed. Bench tests are useful in identifying whether a medication can practically be manipulated and flushed via an enteral feeding tube.