How can I prevent repeated values using math.random?

function generateMedKit(name)
    local MedKits = game.ServerStorage.MedKits:FindFirstChild(name)                     
    local Cords = {"5, 5, 5","10, 10, 10","20, 20, 20","40, 40, 40","80, 80, 80"}
    local randNum = math.random(1,#Cords)
    local chosenValue = Cords[randNum]
            print(chosenValue)
            MedKits.Position = Vector3.new(chosenValue)
            MedKits.Parent = game.Workspace
        end 
generateMedKit("Med1")
generateMedKit("Med2")
generateMedKit("Med3") 

I am making random spawns for a medkit across multiple coordinates. Everthing works, however sometimes I get repeat Coordinates. How can I prevent two identical coordinates from being generated.