Antidepressants. Very "rock and roll".

The report from the attorney general of Colombia came in a tweet which said that the 50-year-old musician had antidepressants, benzodiazepines and opioids in his system, along with THC. It did not further specify the drugs that had been found, and the attorney general’s statement avoided using the word “overdose.”
A report in a major Colombian magazine, Semana, went further, however, reporting that unnamed authorities told its reporters that heroin was part of the drug cocktail in Hawkins’ system, and that he was found to have an enlarged heart.
Semana reported that “forensic doctors were shocked by the size of the drummer’s heart,” at more than 600 grams, and believe that was a factor in Hawkins quickly succumbing to “a cocktail of narcotics.”

Taylor Hawkins Had 10 Drugs in His System, Colombian Authorities Say - Variety