Peter Gillespie, 64, of Windsor, has been sentenced to eight years for the "most serious" known breach of counterfeit medicine in the UK, the MHRA has reported.
Mr Gillespie was found guilty of helping to import two million doses of counterfeit medicines into the UK over five months in 2007.
The case saw fake life-saving drugs infiltrated into the legitimate supply chain, with 900,000 doses reaching pharmacies and patients, according tp the MHRA.
The MHRA recalled Zyprexa, Plavix and Casodex and 700,000 doses were unaccounted for, with 196,000 recovered as a result.
The trial, which was known as Operation Singapore, began in November 2010 and concluded in Croydon Crown Court last week (April 8).
MHRA head of enforcement Mick Deats said this was an "execeptionally rare" case.
"We share the concerns of patients across the UK," Mr Deats said. "All patients have a right to expect that medicines supplied to them are genuine and meet appropriate standards of quality safety and efficacy."
"However, all available information suggests that medicines supplied through the UK legitimate supply chain are genuine and safe to take," he added.
"Against a background of some 850 million prescriptions dispensed in the UK per year, this type of case is exceptionally rare."
Four other men on trial for their involvement in the case were acquitted.