Why is there is bubble in my

Metoject methotrexate injection?

Patients, who have switched to Metoject, the new sub-cutaneous methotrexate injection have been asking why this particular syringe contains an air bubble when previous injections did not.  Advice from independent professionals, has confirmed that the inclusion of an air bubble is better for the patient and, the empty syringe is safer when a bubble is included.

Tony Johnson, Medac’s marketing manager, comments: “The air bubble is included to ensure that when injecting, all of the drug is expelled from the syringe. This guarantees that the patient receives an accurate dosage and that no drug is left in the syringe, making disposal much safer. It also helps prevent leakage from the injection site. The air bubble does not need to be aspirated from the syringe.”

The Department of the Environment backs the claims regarding syringe disposal and commented that if the contents of the syringe could be fully discharged, then the syringe would be considered as contaminated but not hazardous waste i.e. normal clinical waste which is much cheaper and easier to dispose of.

Other syringes do not have an air bubble and will therefore always have a residue in the ‘dead space’ between the plunger and the end of the needle.

The RCN guidelines for nurses on ‘administering subcutaneous methotrexate for inflammatory arthritis’ state that aspiration is not required prior to injection.

An article by Barbara Workman from the Nursing Standard on safe injection techniques cites a study by Quartermaine and Taylor (1995) which suggests that the inclusion of an air bubble is more successful at preventing leakage.