"There is obviously a time when painkillers should be prescribed, but medical professions should be more discerning," Chili Peppers bassist writes
Rapper also unveils video for inspirational single, "Words Are Few"
Singer of Nineties hits "Linger," "Dreams" and "Zombie" dies in London, though a cause of death has yet to be revealed
Heavy metal legends' new album due in March
"I think the right decision at this time is to cancel the show," 'Melodrama' singer says of withdrawn gig