Paul Ferris, in a letter to the editor of the Guardian concerning the above story (12-1-04):

"A 'new theory' about Dylan Thomas says it wasn't drink that killed him but pneumonia potentiated by morphine, medically administered. This is a good explanation of what happened in November 1953 in New York, and I endorse it, having given it twice already in my biographies of Thomas (1977 and 1999).

No doubt the story of Thomas boasting about '18 straight whiskies,' and then succumbing to alcoholic poisoning will endure because it seems a suitable end for a poet. Meanwhile, the story of a man with a bad chest who was given the wrong injection will continue to be revealed at intervals, and fail to catch on."

I could elaborate but I'm sure you don't want me to.