Medicament injection apparatus

The present invention relates to a medicament injection apparatus. It is desirable following injection of a medicament to wait a short time before withdrawing the needle unit from the patient to allow injected medicament to disperse within the patient to reduce the risk of some of the injected medicament escaping through the needle wound and so not being dispersed into the patient as desired. This problem is particularly acute where a patient uses the apparatus to self-administer a dose since, where this waiting period is indicated to a user, the waiting period is a set time independent of whether the size of the dose to be injected. The user often feels that for a small dose it is not as important to leave the needle unit within the body for the full waiting period and so does not allow the waiting period properly to elapse. A medicament injection apparatus is disclosed wherein signal means actuated by a processor for signal the end of a predetermined period of time elapsing from the end of the injection operation wherein the predetermined period of time elapsing is dependent upon the amount of the medicament injected. This has as an advantage the giving of a user confidence that the waiting period for each dose size is important and should be respected.