Emergency departments (EDs) are a crucial element of health care systems as they constitute the interface between hospital and communities. The goals of the ED are to make an initial diagnosis and deliver urgent and critical care 24 hours per day and 365 days a year. Also, many Adverse Drug Events (ADEs) are not identified by emergency physicians. ADEs are injuries resulting from a drug related medical intervention. Their detection, documentation and reporting are essential for adequate medical care and knowledge of risk/benefit profiles of medication throughout their lifecycle. However, a number of studies indicate that in clinical practice the under-reporting of ADEs is a pervasive and widespread problem. The main reasons for under-reporting were difficulty in determining the cause of the ADE, lack of time, poor integration of ADE-reporting systems and uncertainty about reporting procedures. Successful treatment of ADEs depends on the ability of physicians to attribute ADEs to a medication. Some studies have reported that not only pharmacists but also pharmacy student were one of the best health care providers to establish medication history and detected ADEs.

It has also been shown that a clinical pharmacist, within the emergency medical team, can improve the detection of ADE through drug expertise and reliable drug history. This approach has been adopted at Montpellier University Hospital since November 2011. During the initial diagnosis of the ADE, the revision of a drug treatment at risk cannot be carried out in emergency department by the emergency physician. Indeed, the latter intervenes punctually but he is not the patient's referring doctor. Guidance and follow-up of the patient throughout the care journey is the responsibility of the referring physician, sometimes accompanied by the pharmacist. It is therefore very important that a relevant information detected at the hospital can be passed on to the referring health professionals who will review and adapt the treatment. The city-hospital link is essential to guarantee the continuity and the consistence of the care process. When a patient is discharging with the emergency department, the outgoing mail often mentions only the reason for admission, and the information concerning the detection or suspicion of an ADE is not systematically stipulated. However, this information is essential to trigger a process of therapeutic revision (therapeutic modification, therapeutic education, referral to specialized consultations ...) that will prevent the recurrence of the ADE and therefore the readmission to emergency department. To date, the rate of readmission to emergency department after a first visit related to an ADE is between 3.6 and 18.7%.

Our goal is to evaluate the impact at 6 months of a medical-pharmaceutical follow-up and the optimization of the city-hospital link following an admission at emergency department for ADE, on the readmission to emergency department for the same ADE.

This is a single-center randomized, controlled, open-label, two-arm, parallel, "usual information transmission" or "optimized information transmission" study. The duration of a patient's follow-up is 6 months.

Each patient with an occurring ADE detected during emergency department admission could be participating in the study.

Specific management of the experimental group: Sending to the community referring physician by the emergency department an discharge report containing the reason for emergency consultations (report currently made as part of the treatment). Within 72 hours (working hours), the Emergency Clinical Pharmacist contacts the referring physician and the patient's community pharmacist to discuss how to manage the ADE. In parallel, a second report, summary of the ADE (ADE-report), is sent to them. The ADE-report, written and validated by the investigators (emergency physician and clinical pharmacist), includes the type of ADE, the suspected drug(s) and other recommendations: therapeutic modification, referral to specialized consultations (geriatrics ...)

Control group: The emergency department sends to the referring doctor a letter to inform him about the reason of consultations in the emergency department (mail currently realized as part of the care process).

Primary outcome measure: Percentage of patients who had at least one readmission for the same reason in the emergency department within 6 months of the initial exit. This information will be collected during a telephone call with the patient and the referring physician.

Inclusion criteria:

• Patient over 18 years old
• Patient to whom an ADE is detected
• Possibility of carrying out a pharmaceutical consultation/interview
• Patient who has consented to participate
• Patient affiliated to the social welfare policy
• Patient who declared a referent medical doctor

Exclusion criteria:

• ADE linked to an emergency care activity
• Voluntary medical intoxication
• Impossibility of recovering the patient's drug history
• Under 18
• Pregnancy
• Participating in another category 1 interventional drug study