Many people with dysphagia require liquids to be thickened in order to swallow them safely
- people with dysphagia must be assessed and reviewed by an appropriately trained healthcare professional (a speech and language therapist) who will recommend the appropriate fluid consistency and food texture for that individual
Fluid consistency and food texture is graded according to the International Dysphagia Diet Standardisation Initiative (IDDSI) framework which provides a common terminology to describe food textures and fluid consistency (1)
- consists of a continuum of 8 levels ranging from 0 to 7, with drinks measured from Levels 0 to 4 and foods measured from Levels 3 to 7
- level 0 fluids are described as ‘thin’ (e.g. water), Level 3 as ‘moderately thick’ (the same consistency as liquidised food) and Level 4 fluids as ‘extremely thick’ (the same consistency as pureed foods) (1)
- thickening agents can be used to modify the consistency of thin liquids to IDDSI Levels 1, 2, 3 or 4
Thickening agents are typically available as tubs (with scoops) or sachets of powder to be mixed with the liquid that needs thickening
- thickening agents must be mixed appropriately in order to produce the required IDDSI Level for the patient
- too thin and the patient is at risk of aspiration, too thick and the liquid can leave a residue that can be aspirated
- two main types of thickening agent: starch-based (typically modified maize starch) and gum-based
- gums include xanthan, guar, locust bean (aka carob) and carrageenan
- gum-based thickening agents may be more palatable with a ‘slicker’ result, although flavour of food and drink has been shown to deteriorate with increasing thickness regardless of thickening agent used (2)
Macragol laxatives (Polyethylene glycol (PEG) laxative products) and thickening agents:
- the interaction between macrogol laxatives (e.g. Movicol) and starch-based thickening agents, creates a thin, watery liquid
- as an alternative, xanthan gum-based thickening agents can be used to thicken macrogol laxatives and some (e.g. Thick & Easy Clear, Swalloweze Clear) have specific directions for this use
- Advice for healthcare professionals (3):
- there have been reports of a possible potential harmful interaction between polyethylene glycol (PEG) laxatives and starch-based thickeners when they are mixed together
- combining the two compounds can counteract the thickening action and result in a thin watery liquid — patients with swallowing difficulties (dysphagia) are potentially at greater risk of aspiration of the thinner liquid
- avoid directly mixing together PEG laxatives and starch-based thickeners, especially in patients with dysphagia who are considered at risk of aspiration such as elderly people and people with disabilities that affect swallowing
- report suspected adverse drug reactions (ADRs) to the Yellow Card Scheme
Prescribing a thickening agent
- thickening agents are not licensed as medicines. Many are classed as Food for Special Medical Purposes (FSMPs) intended for the dietary management, under medical supervision, of individuals who suffer from dysphagia
- specific brands of thickening agents are listed in UK drug tariffs as prescribable for the management of dysphagia as approved by the Advisory Committee on Borderline Substances (ACBS)
- can be prescribed on NHS FP10 prescriptions in England, Wales and Northern Ireland or GP10 prescriptions in Scotland when endorsed “ACBS” (37-39). Many products are available to buy without prescription, but should only be initiated under medical supervision following individual patient assessment
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