Medicine facts (Part 3): Has my medication gone bad?

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Yow Hui Yin,
PhD, BPharm (Hons), RPh

Article 1 feature image (expiry date)

Did you know that the shelf life of a medicine may be significantly shorter than the stated expiry date depending on the handling and/or storage conditions? A medicine expiry date indicates the date after which the medicine should not be used. In the order words, a manufacturer guarantees the full potency and safety of its intact packaged medicine before the stipulated date.

The requirement of an expiry date on prescription and over-the-counter medicines began in 1979 under the U.S. Food and Drug Administration (FDA) regulations. An expiry date can be found on the medicine outer packaging as well as on the label of bottle and at the end of medicine strip. However, with different expiry descriptions being used by different manufacturers, it is important for consumers to know the meaning of each, as shown below:

Description on packaging Definition
Expires January 2018 Discard 31/01/2018
Best before January 2018 Discard 31/12/2017
Use by/ before January 2018 Discard 31/12/2017
Discard after January 2018 Discard 31/01/2018

Adapted from NHS Berkshire East guidance, ‘Good Practice Guidance 4: Expiry Date Guidelines for Medication’ (2014)

The risk of consuming expired medicines is high because almost all of us keep some medicines at home for emergency purposes or from the leftovers of previous prescriptions.

It is also worth noting that, the expiry date stated by the manufacturer is applicable only to medicines with their container still unopened. Once the medicine container is opened (with the exception of blister packs where each pill is sealed individually), the shelf-life of its content will be reduced significantly due to the contact of the medicine with external factors: water, temperature, air or light.

Proper medication storage can extend the shelf life of the medicine. Typically, medicines should be kept in a dry and cool place (at room temperature < 25 °C). A cabinet or medicine box is an ideal storage for medicines. Nevertheless, some medicines have specific storage requirements; for instance, insulin needs to be kept in the fridge (at temperatures of 2 –  8 °C). The shelf life varies depending on the type of product/formulation as shown below:

Types of product/formulation Suggested shelf life
 

ORAL FORMULATIONS

Tablets & capsule in original blister strips Manufacturer’s expiry date as printed on original packaging
Tablets & capsules in dispensing bottles from pharmacy 6 months from the date of dispensing unless otherwise informed by pharmacist
Tablets & capsules in loose packs 2 months from the date of dispensing unless otherwise informed by pharmacist
Oral liquids in original manufacturer’s packaging 6 months from the date of opening

*For antibiotics, check with pharmacist

Oral liquids prepared by pharmacy Follow the date stated by pharmacist
Glyceryl Trinitrate tablets 8 weeks after the date of opening

*Store in a closed amber glass container

 

EXTERNAL FORMULATIONS

External liquids (e.g. lotions, shampoos & bath oil) 6 months from the date of opening or manufacturer’s recommendation whichever is shorter
Creams/ointments in tubes 3 months from the date of opening or manufacturer’s recommendation whichever is shorter
Creams/ointments in jars or tubs 1 months from date of opening
Creams/ointments in pump dispensers Manufacturer’s expiry date
Creams/ointment decanted from bulk container or specially made for individual Seek pharmacist’s advice
Eye/ear/nose drops or ointments 1 month from the date of opening
 

OTHERS

Inhalers Manufacturer’s expiry date
Insulin (vials/ pens) Unopened: manufacturer’s expiry date when stored in fridge at temperature 2 –  8 °C

Opened: 4 weeks from date of opening and can be kept at room temperature (< 25 °C)

It is often advisable to note the date of opening on the medicine packaging/label and to check the expiry date of your medicine before use. Any medicine with changes in appearance (e.g. colour, texture, odour) should be discarded regardless of the shelf life or the printed expiry date.

This leads us to the next interesting question:  What will happen if I take an expired medicine? Firstly, the effectiveness of the expired medicine may be affected. A medicine may retain up to 90% of its active ingredient for at least 5 years after the labeled expiry date. One may think that if a medicine still retains 90% of its full potency, it is probably not a bad idea to still consume it. However, such practice may place patients at risk of not getting the full effects required, especially for life-saving medicines used for emergency conditions. In addition, some medicines could change chemically or break down to toxic metabolites which may be hazardous to the patient’s health. Moreover, the risk of contamination for opened medicine cannot be discounted. Hence, the potency and safety of expired medicines are always a cause for concern.

All in all, you should avoid taking expired medicines and to store them according to manufacturers’ recommendations while noting the possible change of shelf-life (if stated) once they are opened. It is always better to be safe than sorry. If you are in doubt, always speak to your pharmacist or doctor.

References:

  1. NHS Berkshire East guidance, ‘Good Practice Guidance 4: Expiry Date Guidelines for Medication’ (2014). Accessed on 11 May 2017. http://www.windsorascotmaidenheadccg.nhs.uk/download/care_home_guidance/04.%20Good%20Practice%20Guidance%204.%20Expiry%20dates%20for%20medication.pdf
  2. http://www.nhs.uk/chq/Pages/why-medicines-have-expiry-dates.aspx?CategoryID=73&SubCategoryID=108
  3. http://today.mims.com/topic/medicine-expiry-dates–when-does-it-really-matter-?country=malaysia&elq_mid=10536&elq_cid=13219
  4. http://www.emedexpert.com/tips/expired-meds.shtml
  5. https://www.drugs.com/article/drug-expiration-dates.html
  6. Lee Cantrell. Stability of Active Ingredients in Long-Expired Prescription Medications.Arch Intern Med. 2012;172(21):1685-1687
  7. NHS Sheffield Clinical Commissioning Group, ‘Good Practice Guidance for Care Homes – Expiry Dates’ (2016). Accessed on 17 May 2017. http://psnc.org.uk/sheffield-lpc/wp-content/uploads/sites/79/2013/06/Expiry-Dates-Guidance-Oct-2013.pdf

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