Thickening liquid medicines

Karoline Brennan, Senior Medicines Information Pharmacist, North West Medicines Information CentrePublished

Thickening liquid medicines should not be used routinely: it is difficult to check fluid consistency which can affect whether the medicine is swallowed safely.

General advice

Defining and identifying thickness of fluids and food for patients with swallowing difficulties

How fluid thickness and food texture are defined for patients with swallowing difficulties, and how to find the recommended level for a patient.

Alternatives to thickening liquid medicines

When thickening a liquid medicine it is very difficult to check if you have achieved the appropriate fluid consistency (IDDSI Level) for the patient. This means that the patient may receive a liquid they cannot swallow safely.

Giving solid medicines (usually crushed tablets or opened capsules) with food of the appropriate texture for the patient is likely to be safer than thickening liquid medicines.

See Choosing formulations of medicines for adults with swallowing difficulties.

Thickening liquid medicines

Only thicken liquid medicines if there is no other suitable option.

Thickening small-volume medicines

Thicken one dose at a time, immediately before use.

It may be necessary to thicken a small volume of medicine if a patient needs an unusual dose only achievable with a liquid medicine and is unable to take the liquid medicine in an un-thickened form due to the risk of aspiration.

Medicines formulated as oral solutions and suspensions are generally at concentrations to allow for doses of around 5-20ml. Instructions for thickeners are typically given for thickening 200ml of fluid. There are two possibilities for thickening individual doses of liquid medicines, both of which have risks:

1) Thicken the dose directly

Using this option, it is not possible to determine if the dose has been thickened to the appropriate IDDSI Level.

2) Dilute the dose of medicine to 200ml and then thicken following the manufacturer’s directions for the thickening agent

The patient will need to drink 200ml to receive the full dose. This is unlikely to be acceptable, particularly if they take multiple medicines.

Directions

  • If thickening an individual small-volume dose, sprinkle thickening agent onto the dose of medicine and stir, wait a minute to thicken, and then add more thickener if necessary.
  • It is not possible to properly assess the consistency achieved, making this option unsuitable other than as a last resort.

Thickening large-volume medicines

  • If a liquid medicine must be thickened, only thicken one dose at a time, immediately before use, and only if no other option is available.
  • Sometimes patients are required to take a large volume of a medicine, such as macrogol (PEG) laxatives (e.g. Movicol) and electrolyte replacement therapy (e.g. Dioralyte). If these medicines are necessary, they will need thickening to the appropriate IDDSI Level for the patient.
  • There are few data on liquid medicines mixed with thickening agents and it is not without risk.
  • Do not use starch-based thickeners to thicken macrogol (PEG) laxatives – see Using thickeners of different types for patients with swallowing difficulties for information on drug-thickener interactions.

Directions

  • If thickening a large-volume medicine, follow the instructions for the thickening agent in order to produce the appropriate IDDSI Level.
  • Check the desired consistency has been achieved as best you can.
  • Do not give the medicine if the final product does not appear to be the appropriate consistency.

Other specific areas

Using thickeners of different types for patients with swallowing difficulties

Gum and starch based thickeners are available; drug-thickener interactions are possible and should be avoided.

Storage and regulation of thickeners and thickened fluids

Thickeners and thickened fluids have different storage requirements and are regulated in a particular manner.

Thickening liquid medicines

Thickening liquid medicines should not be used routinely: it is difficult to check fluid consistency which can affect whether the medicine is swallowed safely.

Read more

Swallowing difficulties

All our advice on using medicines safely and effectively in patients with swallowing difficulties