Alan Dean Foster 
Bloodhype 

Pip and Flinx: Book Two.Repler was a humanx-controlled planet, a minor outpost of the flourishing Commonwealth. It housed two of the most terrible threats ever to have faced the material universe. First was the Vom. A vast mass of liquid blackness, it had waited half a million years to be discovered. The wait was over. Second there was Bloodyhype, a killer drug with no known antidote. It caused instant addiction, followed by excruciatingly slow death. Flinx was a sanitation engineer, strictly on the sidelines. But his role in the affairs of the planet soon took on a more ominous aspect.