Additives in medicines ('excipients')

Last updated: February 07, 2020

Key points
  • Additives in a medicine can cause side effects, just like the drug or 'active' ingredient in a medicine.
  • Patients can be intolerant or allergic to additives in medicines. The e-learning below tells you more.
  • However, most patients with lactose intolerance or coeliac disease can tolerate the lactose or wheat starch found in medicines.
  • The eMC website identifies additives in medicines and helps you find alternatives that don't contain it.

Info sources

✦  Pharmaceutical companies publish a document called a Summary of Product Characteristics (SmPC) for every medicine which identifies its additives. You can see SmPCs via the eMC website. Look in section 6.1 for a list of excipients for each medicine.
✦  We have a step-by-step guide that shows you how to use the eMC to find out which medicines contain an excipient and which ones don't.
✦  Some SmPCs are missing from the eMC, but are available via the MHRA website (e.g. certain generic medicines).
✦  The SPS website has information about glutenlactosesoya, and peanut (arachis oil) in medicines, and advice about excipients for vegans.
✦  Excipients in children – the Neonatal and Paediatric Pharmacists' Group has provided a PDF document describing some of the excipients that may pose particular problems for children and babies.

Asking the right questions

When trying to solve a clinical problem you may need to find out about the patient's medical history and any other medicines they are taking (not least because they may already be taking a suspect excipient in another medicine). However, here are some questions that you may want to ask the patient or a healthcare professional specifically in connection with an excipients-related clinical problem; more detail is given in our e-learning below:
  • Timing of medicine administration related to any symptoms? Has a new medicine, or a new brand of an existing medicine, been started shortly before new symptoms were reported?
  • What is the brand name or manufacturer? You need to know this for all medicines suspected to be involved, because excipients vary between different brands and formulations of the same drug. 

  • Is the patient known to react to a particular excipient, or is the reaction suspected?  Patients will often know about problems they have experienced with certain additives or medicines in the past. Has the patient taken other brands or formulations before without any problems?
  • What is the nature of any known or suspected reactions to excipients? You'll need a clear description, as you would for an adverse reaction. 
  • Has the patient had a similar reaction with any other medicine, food or drink? Excipients and additives will be found in other medicines or foods so the patient may have encountered the reaction before.

  • What is the management plan? Don't just identify the potentially causative excipient. Advise about suitable alternative brands/formulations, or a different medicine that does not contain the excipient.
  • Who needs to know? Make sure that any problems related to excipients are clearly communicated to the patient and the patient's GP, so that the offending medicine is not re-prescribed and further exposure to the excipient is avoided. You must also document a potential allergy or intolerance in a patient's notes, to help the patient avoid exposure in the future.

You can improve your knowledge about this subject with our free e-learning. It only takes 15 minutes. Click here to start.