Studies have suggested that fluoxetine might improve neurological recovery after stroke, but the results remain inconclusive. The EFFECTS (Efficacy oF Fluoxetine - a randomisEd Controlled Trial in Stroke) reached its recruitment target of 1500 patients in June 2019. The purpose of this article is to present all amendments to the protocol and describe how we formed the EFFECTS trial collaboration in Sweden. Methods: In this investigator-led, multicentre, parallel-group, randomised, placebo-controlled trial, we enrolled non-depressed stroke patients aged 18 years or older between 2 and 15 days after stroke onset. The patients had a clinical diagnosis of stroke (ischaemic or intracerebral haemorrhage) with persisting focal neurological deficits. Patients were randomised to fluoxetine 20 mg or matching placebo capsules once daily for 6 months. Results: Seven amendments were made and included clarification of drug interaction between fluoxetine and metoprolol and the use of metoprolol for severe heart failure as an exclusion criterion, inclusion of data from central Swedish registries and the Swedish Stroke Register, changes in informed consent from patients, and clarification of design of some sub-studies. EFFECTS recruited 1500 patients at 35 centres in Sweden between 20 October 2014 and 28 June 2019. We plan to unblind the data in January 2020 and report the primary outcome in May 2020. Conclusion: EFFECTS will provide data on the safety and efficacy of 6 months of treatment with fluoxetine after stroke in a Swedish health system setting. The data from EFFECTS will also contribute to an individual patient data meta-analysis. Trial registration: EudraCT 2011-006130-16. Registered on 8 August 2014. ISRCTN, ISRCTN13020412. Registered on 19 December 2014. ClinicalTrials.gov: NCT02683213. Retrospectively registered on 2 February 2016.