Sequence generation {16a}
The pharmacy of the Capital Region of Denmark will pack inbox and label the study medicine and placebo ampoules. The pharmacy is approved by the Danish Health authorities. The randomization will be allocated by the pharmacy and their independent statistician using a random number generator with allocation in a 1:1 fashion with active study medicine and placebo randomized permuted blocks of four. The pharmacy will keep the allocation list and is responsible for generation of the allocation sequence. The pharmacy will not be involved otherwise in the trial. All boxes are identical and has a unique box serial number.Following preparation, the boxes will be shipped to all the medical emergency unit stations in the Capital Region and Region Zealand of Denmark. All units are manned 24 h 7 days a week. The investigators will make sure that all ambulances always have boxes in storage and ready for use. Before each shift, the ambulance staff will make sure that a minimum of two boxes are stored in each ambulance.When a patient is screened and included in the trial by telephone by the RD, the ambulance staff will open one of the study medicine boxes and administrate the study medicine (active or placebo). Following the administration of the study medicine, the ambulance staff will fill out a registration form in REDCap. The registration form can be accessed through a QR code on the study medicine box or through an internet browser. For safety, the ambulance staff will also take a photo of the study medicine box, write an inclusion note in the pre-hospital journal, and bring the empty box to the department at Rigshospitalet. To ensure continuous storage at each ambulance, the ambulance staff will get a new study medicine box from the receiving personnel at the hospital department upon arrival. There will be local storages at different hospitals throughout the regions in case the patient is transported to Rigshospitalet by helicopter.