Article 15 - Storage, Degradation, and Why How You Keep Your Medicine Matters

Storage is part of medicine handling. Heat, light, air, moisture, time, and poor packaging can all affect how a cannabis-based medicine is kept and used.

Good storage does not make a medicine more potent or guarantee a particular effect. It helps protect the product from avoidable changes and helps the patient use the medicine consistently.

Why storage matters

Cannabis-based medicines contain compounds that can change over time. The rate and nature of those changes depend on the product, packaging, formulation, batch, storage conditions, and time since manufacture.

Light, heat, oxygen, and moisture may affect the stability of cannabinoids and aromatic compounds. The visible appearance, smell, texture, and measured composition may change. A change does not automatically mean that a product is unsafe, but it is a reason to check the product information and ask a pharmacist or prescribing clinic for advice.

Do not assume that storage advice for dried flower also applies to oils, capsules, or another formulation. Follow the instructions supplied with the medicine.

Use the original packaging

Keep the medicine in its original, labelled packaging wherever possible. The packaging helps protect the product and provides information such as the product name, strength, batch number, expiry or use-by details, and instructions.

Do not transfer medicine into an unlabelled container. If a different container is needed for a specific reason, ask the pharmacist or prescribing service what is appropriate and how the product should be identified.

Keep the packaging and batch information until the medicine has been used or disposed of according to the supplied instructions. You may need those details if you have a question about a batch or a change in the product.

Protect it from heat and direct light

Store the medicine where it will not be exposed to unnecessary heat or direct sunlight. Avoid leaving it in a vehicle, on a windowsill, beside a radiator, or in another place where temperature can rise significantly.

Do not improvise with freezing, heating, or refrigeration unless the product instructions or a pharmacist specifically tell you to do so. Different formulations have different requirements, and a change in temperature can affect some products or packaging.

Keep moisture under control

Moisture can affect the condition of dried products and may create conditions in which microbial growth becomes a concern. Do not store medicine in a bathroom or another area with frequent steam unless the product instructions specifically support that arrangement.

Do not add water or unapproved moisture products to a prescribed medicine. If dried flower becomes unusually damp, develops an unusual smell, or shows visible signs of mould or contamination, do not use it until you have spoken with your pharmacist or prescribing clinic.

Check the product before use

Before using a medicine, check the label, expiry or use-by information, packaging, and general condition. Look for changes that are unusual for the product, including:

• Damaged, leaking, swollen, or unsealed packaging
• An unexpected smell, colour, texture, or appearance
• Visible mould, foreign material, or contamination
• Oil or liquid that appears different from the supplied product information
• A missing label, unclear batch number, or expired date

Do not taste or inhale a product to test whether it is still suitable. Set it aside and ask the pharmacist, dispensing service, or prescribing clinic what to do.

Storage and consistency

Consistent storage can reduce one avoidable source of variation. If the product is repeatedly exposed to heat, light, air, or moisture, the patient may not be dealing with the same conditions from one use to the next.

This does not mean that every change in effect is caused by storage. Dose, batch, device, technique, sleep, stress, health, and other medicines can also affect response. Storage is one part of the wider treatment picture.

Keep medicines secure

Store prescribed medicines securely and away from children, visitors, pets, and anyone for whom they were not prescribed. Do not share prescribed medicine with another person, even if they report similar symptoms.

Consider who can access the storage area and whether the packaging remains secure when you are travelling or away from home. If you are unsure about safe storage during travel, ask the prescribing service or pharmacist before you leave.

Device care is part of the routine

For vaporised medicines, storage of the medicine and care of the device are connected but not identical tasks. Keep the medicine according to its product instructions and maintain the device according to the device manufacturer's guidance and the instructions supplied by the clinic or pharmacy.

A dirty or damaged device can affect airflow, taste, residue, and consistency. Do not use a damaged device or make unapproved changes to the heating system. Ask the supplier, pharmacist, or prescribing clinic if you are unsure.

What to do if you are unsure

If the medicine was left in a hot car, exposed to water, stored outside the instructions, or has changed in appearance, do not guess. Keep the packaging and batch information, note what happened, and contact the pharmacist, dispensing service, or prescribing clinic.

Ask whether the medicine should be used, replaced, returned, or disposed of. Do not dispose of it in a way that could allow another person or animal to access it.

The honest conclusion

Good storage is simple, but it is not trivial. Keep the medicine in its original packaging, follow the product instructions, protect it from avoidable heat, light, air, and moisture, keep it secure, and ask for advice when its condition is uncertain.

Storage cannot guarantee a clinical result. It can help preserve the product supplied to you and reduce unnecessary variation in how that product is handled from one use to the next.

Sources and further reading

This article is general patient education and does not replace the storage instructions supplied with your medicine. If those instructions differ from general information, follow the product-specific guidance and speak with your pharmacist or prescribing clinician.