Azathioprine (CAS 446-86-6): storage and disposal
A dispensary shelf in a hospital pharmacy or veterinary practice is where azathioprine normally sits, as tablets with some injection stock. The classification is longer than most tablets carry: irritation to skin, eyes and airways, genetic defects, cancer and reproductive harm. It is widely used long term, so old, returned and part-used packs build up faster than staff expect.
- CAS number
- 446-86-6
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Harmful or irritant
Serious health hazard
What to do this week
- Check the label is readable and write down the opened date if it is not already there.
- Check it is stored as toxic stock and apart from the items listed under "Do not store with".
- If you no longer need it, add it to your disposal list so it goes on the next collection.
Safe storage in a school or lab
Returned packs are one of the real problems with this item, so keep returned and unwanted tablets physically apart from stock that can still be dispensed. Store the dispensable stock in a locked, labelled cabinet with a stock record, apart from oxidising stock and from acids, where a reaction could release harmful vapours or gas. Because the substance irritates skin, eyes and airways, anyone counting loose tablets should avoid dust and wear gloves. Injection vials should stay in their cartons so batch and label stay readable.
How to tell it has deteriorated
Start with the container and label: a faded or smudged label, a carton that has been wet, a cap that no longer closes and a pharmacy label with no date are the common faults. Inside, look for crumbling tablets, powder in the bottle, lifted blister foil and any change in colour. For injection vials, look for cracks, a loose crimp and particles. Few specific chemical signs can be given for this substance, so a pack of unknown history, such as one returned by a patient, is treated as expired.
How it must be disposed of
By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a toxic laboratory pack with compatible chemicals.
How it leaves the site is by specialist collection, with returned packs separated from clean unwanted stock and each described on its own line. Tablets should not be tipped out, crushed or flushed, and nothing goes into a sink, a drain or general waste. Healthcare sites normally use 18 01 08*, veterinary practices use 18 02 07*, and a discarded chemical code applies elsewhere. Record the pack type, counts and the condition of the containers. The cancer and genetic statements mean the item is assessed by manual enquiry and quoted online only where the quote path allows.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| Human healthcare setting | 18 01 08* |
| Veterinary setting | 18 02 07* |
| Hazardous waste | Yes |
The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.
Do not store with
- OxidiserToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- AcidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- Acetic acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Hydrochloric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Hydrogen peroxideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities we collect
Usually held as: tablets, injection.
Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.
Where it is commonly held
Hazard statements
- H302 Harmful if swallowed.
- H315 Causes skin irritation.
- H319 Causes serious eye irritation.
- H335 May cause respiratory irritation.
- H340 May cause genetic defects.
- H350 May cause cancer.
- H360 May damage fertility or the unborn child.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P270 Do not eat, drink or smoke when using this product.
- P271 Use only outdoors or in a well-ventilated area.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P317 IF SWALLOWED: Get medical help.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P318 If exposed or concerned, get medical advice.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P332+P317 If skin irritation occurs: Get medical help.
- P337+P317 If eye irritation persists: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Can azathioprine tablets returned by a patient be reused?
No. Returned packs have an unknown history and must be treated as unwanted stock. Keep them apart from dispensable stock, sealed in a labelled container, and include them in the disposal list for specialist collection.
What precautions apply when counting loose azathioprine tablets?
Wear gloves and avoid dust, because the substance irritates skin, eyes and airways and carries genetic and cancer statements. Count over a tray and keep tablets in their original packs where possible.
Which waste code do we use for a veterinary practice?
Veterinary practices normally use 18 02 07* and human healthcare sites 18 01 08*. If the stock is being cleared as a discarded chemical, the base code differs, so describe your situation in the enquiry.
How do we know whether old stock has gone off?
Check for crumbling tablets, lifted foil, discolouration, damp marks and a missing batch or date. Because few chemical signs can be stated, an unknown history alone is enough to class a pack as expired.
